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35 p. ill., Depuis déjà longtemps, les décisions de rembourser ou non une intervention de santé tiennent compte de l'impact de la maladie et de son traitement sur l’espérance de vie et la qualité de vie des patients. Pour l’espérance de vie, il existe une mesure claire : le temps. Par contre, la qualité de vie est plus difficile à quantifier. Pourtant, il est essentiel de savoir la mesurer afin de pouvoir effectuer des comparaisons entre patients atteints de pathologies différentes et/ou recevant des traitements différents. L’EQ-5D est un instrument largement utilisé pour mesurer la qualité de vie liée à la santé (c’est-à-dire l’impact spécifique de la santé ou de la maladie sur la qualité de la vie). Sa version EQ-5D-5L décrit 3 125 états de santé auxquels est attribuée une « valeur » reflétant la qualité de vie, appelée « score d'utilité ». Le Centre fédéral d’Expertise des Soins de santé (KCE) a développé pour la première fois un ensemble de valeurs (matrice de valorisation) pour l’EQ-5D-5L, sur la base d’une vaste enquête auprès d’un échantillon représentatif de la population belge. Cette matrice de valorisation propose, pour chaque problème de santé décrit par l'EQ-5D, une valeur de qualité de vie liée à la santé reflétant les préférences moyennes de la population belge. Lorsqu’il s’agit d’évaluer des interventions de santé, des traitements ou des nouvelles technologies, ces scores d'utilité permettent de faire un arbitrage en fonction tant de la durée de vie que de la qualité de vie. L'étude a été cofinancée par l’EuroQol Research Foundation. AVANT-PROPOS 1 -- MESSAGES CLÉS 2 -- SYNTHÈSE 3 -- 1. NOTE INTRODUCTIVE POUR LES NON-INITIÉS 7 -- 1.1. POURQUOI UN RAPPORT SUR LA MESURE DE LA QUALITÉ DE VIE LIÉE À LA SANTÉ ? 7 -- 1.2. CINQ DIMENSIONS, CINQ DEGRÉS 7 -- 1.3. DE LA DESCRIPTION À L’ÉVALUATION ET À LA COMPARAISON 7 -- 1.4. COMMENT ABORDER CE RAPPORT DE SYNTHÈSE ? 9 -- 2. CONCEPTS-CLÉS 10 -- 2.1. LA QUALITÉ DE VIE LIÉE À LA SANTÉ 10 -- 2.1.1. Définition 10 -- 2.1.2. Les scores d’utilité et les QALY 10 -- 2.1.3. Guidelines belges pour les évaluations économiques 11 -- 2.2. L'INSTRUMENT EQ-5D-5L 11 -- 3. OBJECTIF DE CETTE ÉTUDE 14 -- 4. MÉTHODE 14 -- 4.1. L'ÉCHANTILLON – QUI A PARTICIPÉ ET QUAND 14 -- 4.2. QUELLES TECHNIQUES D'ENQUÊTE ONT ÉTÉ UTILISÉES ? 17 -- 4.2.1. L'exercice Time Trade-Off composé 17 -- 4.2.2. Expérience de choix discret 19 -- 4.2.3. Contrôle de la qualité des données 19 -- 4.3. ANALYSE DES DONNÉES 19 -- 5. LA MATRICE DE VALORISATION EQ-5D-5L BELGE 20 -- 5.1. REPRÉSENTATIVITÉ DE L'ÉCHANTILLON 20 -- 5.2. RÉSULTATS DE L'EXERCICE CTTO 20 -- 5.2.1. Dispersion et variation 20 -- 5.2.2. Validité des résultats cTTO 21 -- 5.2.3. Inconscience, douleur et gêne 21 -- 5.3. RÉSULTATS DE L'EXPÉRIENCE DC 22 -- 5.4. TABLEAU FINAL DE LA MATRICE DE VALORISATION EQ-5D-5L BELGE 22 -- 6. EN QUOI LA NOUVELLE MATRICE BELGE REPRÉSENTE-T-ELLE UN PROGRÈS ? 24 -- 6.1. LES POINTS FORTS DE CETTE MATRICE DE VALORISATION 24 -- 6.2. COMPARAISON AVEC LA MATRICE DE VALORISATION 3L ET AVEC LES MATRICES 5L -- D'AUTRES PAYS 25 -- 6.2.1. Un éventail plus large de scores d’utilité avec cinq niveaux de sévérité 25 -- 6.2.2. La matrice de valorisation belge diffère de celle des pays voisins 27 -- 6.3. OÙ ET QUAND APPLIQUER LA NOUVELLE MATRICE DE VALORISATION BELGE EQ-5D-5L ? 29 -- 6.3.1. Utiliser l’EQ-5D-5L comme PROM 29 -- 6.3.2. Une vision réaliste de l'efficacité et du rapport coût-efficacité 29 -- 6.3.3. Une meilleure vision de la santé publique 30 -- RECOMMANDATIONS 31 -- RÉFÉRENCES 32

Background Bayesian methods, with the predictive probability (PredP), allow multiple interim analyses with interim posterior probability (PostP) computation, without the need to correct for multiple looks at the data. The objective of this paper was to illustrate the use of PredP by simulating a sequential analysis of a clinical trial. Methods We used data from the Laryngobloc trial that planned to include 480 patients to demonstrate the equivalence of success between a laryngoscopy performed with the Laryngobloc® device and a control device. A crossover Bayesian design was used. The success rates of the two laryngoscopy devices were compared. Interim analyses, computed from random numbers of subjects, were simulated. Results The PostP of equivalence rapidly reached the predefined bound of 0.95. The PredP computed with an equivalence margin of 10% reached the efficacy bound between 352 and 409 of the 480 included patients. If a frequentist analysis had been made on the basis of 217 out of 480 subjects, the study would have been prematurely stopped for equivalence. The PredP indicated that this result was nonetheless unstable and that the equivalence was, thus far, not guaranteed. Conclusions Based on these interim analyses, we can conclude with a sufficiently high probability that the equivalence would have been met on the primary outcome before the predetermined end of this particular trial. If a Bayesian approach using PredP had been used, it would have allowed an early termination of the trial by reducing the calculated sample size by 15–20%.

Objectif de l’étude Les ressources humaines, matérielles et financières étant limitées, l’organisation du système de soins doit permettre une allocation des ressources efficiente. La prise en charge des cancers amène à des soins spécifiques et répétitifs pour lesquels le remboursement des frais de transports représente un coût important. Nous avons réalisé une analyse du surcoût de transport, liés à la prise en charge des patients franciliens, dans un centre autre, que le centre de radiothérapie le plus proche de leur domicile. Matériel et méthodes À partir de données de l’Agence régionale de santé d’Île-de-France, nous avons créé un modèle évaluant le surcoût lié aux transports engendrés par la prise en charge d’un patient en radiothérapie à distance de son domicile. Afin de prendre en compte les incertitudes liés aux hypothèses faites dans l’élaboration du modèle nous avons réalisés des analyses de sensibilité déterministe et probabiliste. Résultats Dans le cas de base, le surcoût annuel lié au transport était de 841 176 euros en Île-de-France. L’analyse de sensibilité probabiliste rapporte un surcoût total annuel de 2 817 481 euros. Conclusion Nos résultats se rapprochent d’un rapport de l’Inspection générale des affaires sociales publié en juillet 2011 qui pointait alors un surcoût compris entre 4 et 6 millions d’euros annuels. La prise en charge à distance de leur domicile des patients atteints de cancer participe à une dégradation de la qualité de vie liée aux temps de transport, à un retard à la prise en charge de potentielles complications des traitements et à la diffusion de maladies infectieuses, telle que le COVID-19, et de bactéries résistantes aux antibiotiques.

The concentration of the dose delivered by protons at the end of their path, the Bragg peak, has the potential to improve external radiotherapy treatments. Unfortunately, the main strength of the protons, their finite range, is also their greatest weakness. Any uncertainty on the range may lead to inadequate target coverage or excessive toxicity. The uncertainties have multiple origins and include, among others, ballistic errors, morphological modifications or inaccurate estimations of the physical quantities necessary to predict the proton range. Uncertainties have been part of daily practice in conventional radiotherapy with X-rays for a long time. However, dose distributions delivered with X-rays are much less sensitive to uncertainties than the ones delivered with protons. This relative insensitivity enabled the management of uncertainties through safety margins using a simple formalism. The conditions of validity of this formalism are much more restrictive for proton therapy, leading to the need of developing new tools and adapted strategies to manage accurately these uncertainties. The objective of this paper is to present a vision for the management of uncertainties in proton therapy in the continuity of formalisms established for X-rays. The latter are first summarized before discussing the necessary developments in order to consistently apply them to protons.

The care pathway of cancer patients is complex and therefore difficult to define. The oral anticancers (AKPO) have shown their benefits to patients and health professionals, however, the risks induced on the care pathway remain unknown. The objective of the study is to define, quantify the risks from AKPO and their effects on the care pathway (breakdown [Ds], rupture [Rt]). From the proposed care pathway model, FMEA method is used to analyze risks. For the 3 identified processes (1 monotherapy, 2 bitherapies: 2 AKPO or 1 AKPO/1 AKIV), analysis revealed an average of 91 risks, 173 Ds, 147 Rt, increased for 1 AKPO/1 AKIV therapy. The administration and delivery are the most risky steps. The lack of training and information of patients and healthcare professionals generates 80% of Ds and Rt. This model confirms the complexity, variability of the care pathway. The development of actions to improve town-hospital coordination and exchange of information is required to optimize and secure the route, confirming the objectives of "Plan Cancer 3".

Patterns of multimorbidity, the co-occurrence of two or more chronic diseases, may not be constant across populations. Our study objectives were to compare prevalence estimates of multimorbidity in the Aboriginal population in Canada and a matched non-Aboriginal Caucasian population and identify the chronic diseases that cluster in these groups.We used data from the 2005 Canadian Community Health Survey (CCHS) to identify adult (≥ 18 years) respondents who self-identified as Aboriginal or non-Aboriginal Caucasian origin and reported having 2 or more of the 15 most prevalent chronic conditions measured in the CCHS. Aboriginal respondents who met these criteria were matched on sex and age to non-Aboriginal Caucasian respondents. Analyses were stratified by age (18-54 years and ≥ 55 years). Prevalence was estimated using survey weights. Latent class analysis (LCA) was used to identify disease clusters.A total of 1642 Aboriginal respondents were matched to the same number of non-Aboriginal Caucasian respondents. Overall, 38.9% (95% CI: 36.5%-41.3%) of Aboriginal respondents had two or more chronic conditions compared to 30.7% (95% CI: 28.9%-32.6%) of non-Aboriginal respondents. Comparisons of LCA results revealed that three or four clusters provided the best fit to the data. There were similarities in the diseases that tended to co-occur amongst older groups in both populations, but differences existed between the populations amongst the younger groups.We found a small group of younger Aboriginal respondents who had complex co-occurring chronic diseases; these individuals may especially benefit from disease management programs.Grappes de multimorbidité chez les Autochtones et chez les non-Autochtones d'origine blanche au Canada.Les profils de multimorbidité, c'est-à-dire la présence concomitante de deux maladies chroniques ou plus, ne sont pas nécessairement constants d'une population à l'autre. Les objectifs de notre étude étaient de comparer les estimations relatives à la prévalence de la multimorbidité entre une population canadienne autochtone et une population appariée non autochtone d'origine blanche et de définir les grappes de maladies chroniques caractérisant ces deux groupes.Nous avons utilisé les données de l'Enquête sur la santé dans les collectivités canadiennes (ESCC) pour cibler les répondants adultes (18 ans et plus) ayant déclaré être d'origine autochtone ou d'origine non autochtone blanche et être atteints d'au moins 2 des 15 maladies chroniques les plus fréquentes visées par l'ESCC. Les Autochtones répondant à ces critères ont été appariés en fonction du sexe et de l'âge à des non-Autochtones d'origine blanche. Les analyses ont été stratifiées par âge (18 à 54 ans, 55 ans et plus). Nous avons estimé la prévalence en utilisant la pondération employée dans l'enquête. Nous avons procédé à une analyse de structure latente (ASL) pour définir les grappes de maladies.Nous avons apparié 1 642 répondants autochtones au même nombre de répondants non autochtones d'origine blanche. Sur l'ensemble, 38,9 % (IC à 95 %: 36,5 % à 41,3 %) des Autochtones étaient atteints de deux maladies chroniques ou plus, contre 30,7 % (IC à 95 %: 28,9 % à 32,6 %) des non-Autochtones. La comparaison des résultats de l'ASL a révélé que le meilleur ajustement aux données était obtenu avec trois grappes ou avec quatre grappes. Alors que les maladies concomitantes qui se manifestaient chez les personnes les plus âgées des deux populations avaient tendance à être similaires, les groupes plus jeunes de ces deux populations présentaient des différences.Un petit groupe de répondants autochtones dans le groupe des plus jeunes présentait un profil complexe de maladies chroniques concomitantes. Ces personnes tireraient sans doute grand profit de programmes de gestion des maladies.

Healthcare is a labor-intensive sector in which half of the expenses are dedicated to human resources. Therefore, policy makers, at national and internal levels, attend to the number of practicing professionals and the skill mix. This paper aims to analyze the European forecasting model for supply and demand of physicians.To describe the forecasting tools used for physician planning in Europe, a grey literature search was done in the OECD, WHO, and European Union libraries. Electronic databases such as Pubmed, Medine, Embase and Econlit were also searched.Quantitative methods for forecasting medical supply rely mainly on stock-and-flow simulations and less often on systemic dynamics. Parameters included in forecasting models exhibit wide variability for data availability and quality. The forecasting of physician needs is limited to healthcare consumption and rarely considers overall needs and service targets. Besides quantitative methods, horizon scanning enables an evaluation of the changes in supply and demand in an uncertain future based on qualitative techniques such as semi-structured interviews, Delphi Panels, or focus groups. Finally, supply and demand forecasting models should be regularly updated. Moreover, post-hoc analyze is also needed but too rarely implemented.Medical human resource planning in Europe is inconsistent. Political implementation of the results of forecasting projections is essential to insure efficient planning. However, crucial elements such as mobility data between Member States are poorly understood, impairing medical supply regulation policies. These policies are commonly limited to training regulations, while horizontal and vertical substitution is less frequently taken into consideration.

The objective of this study was, first, to document the psychometric characteristics of a measure of the older adults' socioeconomic status and, secondly, to test the effect of the socioeconomic status on the association between the older adults perceived need to improve their mental health and their use of services in the general medical sector for psychological distress symptoms taking into account the effect of age and gender.Data used in this study come from the ESA study (Enquête sur la santé des ainés) on mental health and aging, conducted in 2005-2008 using a probabilistic sample (n=2811) of the older adult population aged 65 years and over living at home in Quebec.Our results showed that a measurement model of the older adults' socioeconomic status including an individual-level (SES_I) and an area/contextual-level dimension of socioeconomic deprivation (SES_C) was plausible. The reliability of the SES index used in the ESA research program was .92. Our results showed that women (b=-.43) and older people (b=-.16) were more at risk to have a disadvantaged socioeconomic status. However, our results did not show evidence of a significant association between the older adults' socioeconomic status, their perception of a need to improve their mental health and the use of medical services for psychological distress symptoms in the general medical sector in the older adult population in Quebec.Our results do not support the idea suggested in other studies that socioeconomic status has an effect on the older adults use of services for psychological distress symptoms in the general medical sector and suggest that in a context where medical health services are provided under a public insurance programme context, the socioeconomic status does not influence access to services in the general medical sector in the older adult population.

Survival analyses focus on the occurrences of an event of interest, in order to determine risk factors and estimate a risk. Competing events prevent from observing the event of interest. If there are competing events, it can lead to a bias in the risk's estimation. The aim of this article is to explain why Cox model is not appropriate when there are competing events, and to present Fine and Gray model, which can help when dealing with competing risks.

In Basse-Normandie, the population over 65 years old will expend more rapidly between 2007 and 2042 (+11.6%) than the rest of the French population (+9.2%). The same population of Basse-Normandie will get old in the 15 years to come. The impact of these demographic changes over the activity in the gynecology-obstetrics field is not clearly identified. Although we cannot predict the technical and scientific developments in the next 15 years, we are presenting a model allowing to hypothesize about changes of gynecology and obstetrics according to population's aging.We have established a projection model for the realizable surgical acts in obstetrics and gynecology in accordance with the aging of the population in Basse-Normandie. The study was realized based on the acts concerning the cesarean sections (C-section), tubal sterilization, hysteroscopy and hysterectomy as well as ovarectomy and breast surgery. For each activity branch, the codes of the Classification commune des actes médicaux (CCAM) were selected and then removed from the Programme médicalisé des systèmes d'information (PMSI) database. We have used and adapted the Omphale model of the National Statistics and Economical Studies Institute and we have applied it for the period of 2009-2025.Our projection model has permeated to show a 5.5% regression of the C-section acts, a 2% incretion of the hysterectomies and hysteroscopies, 7.7% of ovarectomies as well as a 9.8% augmentation of the breast surgeries. However, we predict a 11.8% diminution of the sterilizations by tubal implants. Globally, the activity in obstetrics and gynecology will remain constant with an insignificant augmentation of 46 acts (0.01%).In Basse-Normandie, the surgical activity in gynecology-obstetrics will moderately increase in the next 15 years. This constant activity signifies that there is no need to form more residents than the number of practitioner to retire. The interest of this model is that it is applicable at a national level and it permits to confront the demographic data and the projections of different activities.

International audience; PurposeTo compare the dosimetric results of different techniques of dynamic intensity modulated radiation therapy (IMRT) in patients treated for a pelvic cancer with nodal irradiation.Patients and methodsData of 51 patients included prospectively in the Artpelvis study were analyzed. Thirty-six patients were treated for a high-risk prostate cancer (13 with helical tomotherapy, and 23 with Rapid’Arc®) and 15 patients were treated for a localized anal cancer (nine with helical tomotherapy and six with Rapid’Arc®). Plan quality was assessed according to several different dosimetric indexes of coverage of planning target volume and sparing of organs at risk.ResultsAlthough some dosimetric differences were statistically significant, helical tomotherapy and Rapid’Arc provided very similar and highly conformal plans. Regarding organs at risk, Rapid’Arc® provided better pelvic bone sparing with a lower non-tumoral integral dose.ConclusionIn pelvis cancer with nodal irradiation, Rapid’Arc and helical tomotherapy provided very similar plans. The clinical evaluation of Artpelvis study will verify this equivalence hypothesis.; ObjectifComparaison dosimétrique entre différentes techniques de radiothérapie conformationnelle avec modulation d’intensité (RCMI) rotationnelles chez des patients traités pour un cancer pelvien avec irradiation ganglionnaire.Patients et méthodesLes données dosimétriques de 51 patients inclus prospectivement dans le protocole Artpelvis ont été analysées. Trente-six patients atteints d’un cancer de prostate à haut risque ont été traités, dont 13 par un appareil de tomothérapie hélicoïdale et 23 par RapidArc®. Quinze patients atteints un cancer du canal anal localement évolué ont été traités, dont neuf par un appareil de tomothérapie hélicoïdale et six par RapidArc®. L’analyse a porté sur la comparaison de différents indices de qualité dosimétriques pour les volumes cibles prévisionnels et sur les doses reçues aux organes à risque.RésultatsMalgré de légères différences, l’analyse des paramètres dosimétriques a montré que les deux techniques généraient une bonne et semblable couverture des volumes cibles prévisionnels, conforme à la prescription et aux contraintes prédéfinies. En ce qui concerne les organes à risque, les doses délivrées au bassin et la dose intégrale étaient légèrement plus élevées avec la tomothérapie hélicoïdale.ConclusionPour des cancers pelviens traités avec irradiation une ganglionnaire, le RapidArc®et la tomothérapie hélicoïdale permettent d’obtenir des résultats dosimétriques équivalents. L’évaluation du suivi clinique de l’étude Artpelvis permettra de vérifier cette hypothèse d’équivalence.

We read with great interest the article by Folse and colleagues ([1][1]). Their conclusion that “risk modeling may provide information that allows stratification of patients by disease risk, with alternate strategies of … screening and/or preventative treatment” has major potential

In the psychological literature, two concepts are often used to approach psychological and social adaptation: defense mechanisms and coping strategies. Many empirical studies deal with these strategies independently of each other. However, the nature of their relationship is still debated, making empirical studies necessary jointly evaluating these two types of strategies to better reflect the adaptive process.To test Chabrol and Callahan's theoretical model of the relationship between defence mechanisms and coping strategies. According to theses authors, defence mechanisms and coping strategies are distinct mechanisms, functionally organized: defenses appear first and modulate the emergence of coping strategy defenses through threat representation.Ninety-four young adult volunteers completed the Coping Inventory for Stressful Situations (CISS), the Defense Style Questionnaire (DSQ-40) and the Perceived Stress Scale (PSS14). The data were treated according to the structural equation modeling method.Overall, the results support the theoretical model proposed by Chabrol and Callahan. The statistical model provides a good fit to the data (chi(2)/df=18.62/22=.85, P=.67, RMSEA=.00 (90% CI: .00-.07), CFI=1, TLI=1.04). It explains from 7 to 24% of coping variability scores (Avoidant Coping: R(2)=.07, P.01; emotional coping and problem-focused coping: R(2)=24, P.01). Results also show that the relationships between defence mechanisms and copings strategies are mediated by perceived distress and perceived controllability. Defence impact on coping strategies is not the same whether one considers problem-focused coping or emotional and avoidant coping. Immature and mature defences' impact on problem-focused coping is underpinned by a simple mediation: perceived controllability. Defences' impact on emotional coping and avoidant coping is more complex and underpinned by a double mediation: first by the perceived controllability and then, in a second time, the perceived distress. Finally, the results show the existence of a feedback loop from emotional copings to immature defences.It is now clearly relevant for the therapist to simultaneously work on defence mechanisms and coping strategies without assimilating these two categories of processes. Such work involves being able to identify them in their specificities. One of the crucial therapeutic targets is to understand the role of defences on the mental construction of reality in order to maximize adaptive reactions, critical in stress management.

The use of hierarchical models in public health research is recently increasing in order to study all the factors explaining health outcomes. Thus, a better understanding of those models is needed first to identify questions that may be answered by using them and also to be aware of there limitations. On the one hand, hierarchical models managed to take into account the hierarchical structure of the data allowing a better estimation of the effects of the explanatory variables and the study of the impact of the "environment" (i.e.: neighborhood, treatment center, same clinical trial…) on health outcomes. They also allow the study of factors that may explain this impact of the "environment". On the other hand, they are more complex and a reflection on which determinant to include and how the environment is supposed to impact patients' health is much needed. This article reviews the rationale for using hierarchical models in public health research and especially in nephrologic research. We attempt to give a simple presentation of these models and to illustrate their results and potential use in the field of nephrology, as well as their limits.

"Critical Care Units" are intended to admit patients with multiple organ failure. The severity of patients admitted is variable. The aim of the study was to estimate the number of days that an optimum care organization could release, and therefore the additional admissions that would have been allowed. Estimates of earnings related to the various supplements were carried out jointly.Reporting days associated or not with a resuscitation care during the year 2011 in an ICU of a university hospital (16 beds), optimized patient flow simulation, and computation of medical act inducing financial supplements.Six hundred and fifty-seven patients (SAPS II from 0 to 110, 41% ventilated more than 48hours, mortality=26%) were admitted representing 5095days (occupancy rate=87%). Two hundred and twenty-two patients (34%) did not trigger supplement for resuscitation care for 415days in the unit. Four hundred and thirty-five patients have triggered this supplement representing 4680days, including 3035days with resuscitation care and 1645 (35% of days valued resuscitation, 32% of total days) without any. The entire year 2011 has generated earnings of 3,980,192€. Optimization of management would have allowed the admission of additional 235 to 295 patients and potential additional earnings from 524,735€ to 1,063,804€, depending on the occupancy rate chosen (80% or real 2011s) and the severity of discharged patients.Optimization of the patients flow between "Critical Care", Intensive Care and Continuous Monitoring Units would increase the number of patients admitted in "Critical Care" Units without any financial loss related to supplements.

A predictive model is a mathematical expression estimating the probability of pregnancy, by combining predictive variables, or indicators. Its development requires three successive phases: formulation of the model, its validation--internal then external--and the impact study. Its performance is assessed by its discrimination and its calibration. Numerous models were proposed, for spontaneous pregnancies, IUI and IVF, but with rather poor results, and their external validation was seldom carried out and was mainly inconclusive. The impact study-consisting in ascertaining whether their use improves medical practice--was exceptionally done. The ideal ART predictive model is a "Center specific" model, helping physicians to choose between abstention, IUI and IVF, by providing a reliable cumulative rate of pregnancy for each option. This tool would allow to rationalize the practices, by avoiding premature, late, or hopeless treatments. The model would also allow to compare the performances between ART Centers based on objective criteria. Today the best solution is to adjust the existing models to one's own practice, by considering models validated with variables describing the treated population, whilst adjusting the calculation to the Center's performances.

While there is a large body of research indicating that individuals with moderate to severe dementia are unfit to drive, relatively little is known about the driving performance of older drivers with mild cognitive impairment (MCI). The aim of the current study was to examine the driving performance of older drivers with MCI on approach to intersections, and to investigate how their healthy counterparts perform on the same driving tasks using a portable driving simulator. Fourteen drivers with MCI and 14 age-matched healthy older drivers (aged 65-87 years) completed a 10-min simulator drive in an urban environment. The simulator drive consisted of stop-sign controlled and signal-controlled intersections. Drivers were required to stop at the stop-sign controlled intersections and to decide whether or not to proceed through a critical light change at the signal-controlled intersections. The specific performance measures included; approach speed, number of brake applications on approach to the intersection (either excessive or minimal), failure to comply with stop signs, and slower braking response times on approach to a critical light change. MCI patients in our sample performed more poorly than controls across a number of variables. However, because the trends failed to reach statistical significance it will be important to replicate the study using a larger sample to qualify whether the results can be generalised to the broader population.

Despite their ubiquity and ecological significance in temperate ecosystems, the behavioural ecology of earthworms is not well described. This study examines the mechanisms that govern aggregation behaviour specially the tendency of individuals to leave or join groups in the compost earthworm Eisenia fetida, a species with considerable economic importance, especially in waste management applications. Through behavioural assays combined with mathematical modelling, we provide the first evidence of self-assembled social structures in earthworms and describe key mechanisms involved in cluster formation. We found that the probability of an individual joining a group increased with group size, while the probability of leaving decreased. Moreover, attraction to groups located at a distance was observed, suggesting a role for volatile cues in cluster formation. The size of earthworm clusters appears to be a key factor determining the stability of the group. These findings enhance our understanding of intra-specific interactions in earthworms and have potential implications for extraction and collection of earthworms in vermicomposting processes.

30 p. ill. D’ici 15 ans, 1 belge sur 5 aura plus de 65 ans, et presque 3% de la population sera âgée de plus de 85 ans. Ayant à l’œil le vieillissement de la population, les décideurs politiques ont demandé au Centre Fédéral d’expertise des soins de santé (KCE) une estimation scientifique du nombre de lits nécessaires dans les maisons de repos au cours des 15 prochaines années. Grâce à la collaboration avec le Bureau fédéral du Plan, un modèle de projection a été développé. Les estimations réalisées indiquent que le nombre total de lits nécessaires à l’horizon 2025 est compris dans une fourchette allant de 149.000 à 177.000 lits, soit une augmentation annuelle de 1.600 à 3.500 lits supplémentaires selon les scénarios. La limite inférieure de 149.000 lits n’est toutefois suffisante que si l’offre de soins à domicile augmentait de 50% au-delà du développement requis par le vieillissement. Les 15 prochaines années doivent être considérées comme une période de grâce. Après 2025, la demande sera plus forte encore. 1. INTRODUCTION 4 -- 2. ORGANISATION ET FINANCEMENT DES SOINS DE LONGUE DUREE EN BELGIQUE 4 -- 3. LES PRINCIPAUX SERVICES DE SOINS DE LONGUE DUREE 5 -- 4. GESTION ET RESPONSABILITÉS 7 -- 4.1. RÉPARTITION DES RESPONSABILITÉS 7 -- 4.2. PROTOCOLES D’ACCORD 7 -- 4.3. DIFFERENCES REGIONALES AU NIVEAU DES CRITERES DE PROGRAMMATION POUR LES -- MAISONS DE REPOS POUR PERSONNES AGEES ET LES MAISONS DE REPOS ET DE SOINS 8 -- 5. TENDANCES EN MATIERE D’OFFRE ET D’UTILISATION DE SOINS DE LONGUE DUREE 9 -- 6. OBJECTIFS DE L’ÉTUDE 10 -- 7. ELABORATION D’UN MODELE DE PROJECTION A LONG TERME 10 -- 7.1. ETUDE DE LA LITTERATURE : LES DETERMINANTS DE L’UTILISATION DES SOINS DE LONGUE DUREE PAR LES PERSONNES AGEES 10 -- 7.1.1. Variables prédisposantes 11 -- 7.1.2. Les variables relatives aux besoins 11 -- 7.1.3. Variables facilitantes 11 -- 7.2. ETUDE DE LA LITTÉRATURE : MODÈLES DE PROJECTION POUR LES SOINS DE LONGUE DURÉE 11 -- 7.2.1. Caractéristiques des modèles 11 -- 7.2.2. Résultats des modèles 13 -- 7.3. BASES DE DONNEES DISPONIBLES EN BELGIQUE POUR CONSTRUIRE UN MODELE DE -- PROJECTION 13 -- 7.4. SPÉCIFICATION DU MODÈLE 14 -- 7.5. MODELISATION DE L’INCAPACITE EN UTILISANT L’ENQUETE DE SANTE PAR INTERVIEW 15 -- 7.6. TRANSITIONS DE MODELISATION DANS DES SITUATIONS DE SLD 16 -- 7.6.1. Stratégie d’estimation 16 -- 7.6.2. Probabilités de transition 16 -- 8. EVOLUTION PREVUE DANS LES STRUCTURES RESIDENTIELLES 18 -- 8.1. EVOLUTION GLOBALE, SCÉNARIO DE BASE 18 -- 8.1.1. Caractéristiques du scénario de base 18 -- 8.1.2. Résultats du scénario de base 18 -- 8.2. SCÉNARIOS ALTERNATIFS 22 -- 8.2.1. Scénarios alternatifs pour l’incapacité 22 -- 8.2.2. Scénarios alternatifs à propos de la situation familiale 22 -- 8.2.3. Scénario alternatif à propos des soins à domicile 23 -- 8.2.4. Résultats des scénarios alternatifs 23 -- 9. CONCLUSIONS GÉNÉRALES 26 -- 9.1. EXIGENCES DE CAPACITE POUR LES ETABLISSEMENTS DE SOINS POUR LA PERIODE 2010- -- 2025 26 -- 9.2. VARIATIONS GÉOGRAPHIQUES 26 -- 9.3. SENSIBILITE A DES HYPOTHESES ALTERNATIVES RELATIVES A L’INCAPACITE ET A LA -- SITUATION FAMILIALE 27 -- 9.4. DEVELOPPER LES SOINS A DOMICILE ? 27 -- 9.5. LES PROJECTIONS À LONG TERME 28 -- 9.6. REUNION DES PARTIES PRENANTES DU SECTEUR 29

31 p. ill. Over 15 jaar is 1 op 5 Belgen ouder dan 65 jaar, en bijna 3% van de bevolking ouder dan 85. Met het oog op de vergrijzing vroegen de beleidsmakers aan het Federaal Kenniscentrum voor de Gezondheidszorg (KCE) een wetenschappelijke raming van het aantal plaatsen die de volgende 15 jaar in rusthuizen nodig zullen zijn. Dankzij de samenwerking met het Federaal Planbureau werd er een projectiemodel ontwikkeld. Daaruit blijkt dat er 149.000 tot 177.000 bedden zullen nodig zijn in 2025. Jaarlijks komt dit neer op 1.600 tot 3.500 nieuwe plaatsen, afhankelijk van het scenario. Deze toename zou gedeeltelijk kunnen worden opgevangen door meer thuiszorg te organiseren. Maar zich beperken tot het minimum van 149.000 bedden is alleen haalbaar als het aanbod van de thuiszorg met de helft toeneemt, bovenop de uitbreiding die alleszins nodig zal zijn door de vergrijzing. De periode tot 2025 moet worden beschouwd als een ‘inloopperiode’. Daarna zal de vraag zelfs nog meer toenemen.

We investigate human postural sway velocity time series by computing two dynamical statistics quantifying the smoothness (the central tendency measure or CTM) and the regularity (the sample entropy or SampEn) of their underlying dynamics. The purpose of the study is to investigate the effect of aging and vision on the selected measures and to explore the nature of postural dynamics by performing surrogate data tests. A group of 14 young subjects was compared to a group of 11 older healthy subjects in two visual conditions: with eyes open (EO) and with eyes closed (EC). The results suggest that vision and age do not influence the two statistics of the velocity data in the same way. More specifically, the smoothness statistic is able to detect the aging effect. The regularity measure is sensitive to the visual feedback removal. In contrast with some findings in the literature, the results of the surrogate data tests indicate that the center of pressure velocity dynamics are stochastic and are not produced by a purely determinisitic behavior. Finally, we discuss some potential implications of our results in terms of postural control mechanisms.

The objective of this work is to estimate the trends of the incidence of breast cancer until 2018, in the French context on the basis of an age cohort model. The model extrapolates the trend of incidence rate per generation and age, incorporates the effects of demographic changes in the female population in terms of size and age structure and simulates the impact of the withdrawal of the use of hormone therapy for menopause (HTM) under different assumptions. The results suggest a continuous growth in the number of incident cases that would increase from 49,814 to 64,621 between 2005 and 2018. Changes in incidence following the HTM use withdrawal, should be moderate and transient. The most important epidemiological parameters in explaining the future incidence of breast cancer remains the "cohort" effect that continues to have a significant impact until the extinction of cohorts for which the increase was more marked (birth years 1920 to 1945). This factor alone explains 18% of the growth in the number of incident cases in 2018, while the effect of population growth account for 6.6%, the cessation of HTM a 6.4% decrease and aging a 4.6% growth.

Summary A country-specific FRAX® model was developed from the epidemiology of fracture and death in Belgium. Fracture probabilities were identified that corresponded to currently accepted reimbursement thresholds. Introduction The objective of this study was to evaluate a Belgian version of the WHO fracture risk assessment (FRAX®) tool to compute 10-year probabilities of osteoporotic fracture in men and women. A particular aim was to determine fracture probabilities that corresponded to the reimbursement policy for the management of osteoporosis in Belgium and the clinical scenarios that gave equivalent fracture probabilities. Methods Fracture probabilities were computed from published data on the fracture and death hazards in Belgium. Probabilities took account of age, sex, the presence of clinical risk factors and femoral neck bone mineral density (BMD). Fracture probabilities were determined that were equivalent to intervention (reimbursement) thresholds currently used in Belgium. Results Fracture probability increased with age, lower BMI, decreasing BMD T-score and all clinical risk factors used alone or combined. The 10-year probabilities of a major osteoporosis-related fracture that corresponded to current reimbursement guidelines ranged from approximately 7.5% at the age of 50 years to 26% at the age of 80 years where a prior fragility fracture was used as an intervention threshold. For women at the threshold of osteoporosis (femoral neck T-score = −2.5 SD), the respective probabilities ranged from 7.4% to 15%. Several combinations of risk-factor profiles were identified that gave similar or higher fracture probabilities than those currently accepted for reimbursement in Belgium. Conclusions The FRAX® tool has been used to identify possible thresholds for therapeutic intervention in Belgium, based on equivalence of risk with current guidelines. The FRAX® model supports a shift from the current DXA-based intervention strategy, towards a strategy based on fracture probability of a major osteoporotic fracture that in turn may improve identification of patients at increased fracture risk. The approach will need to be supported by health economic analyses.

In front of the explosion of the costs of the curative care, the conceptualization of the preventive theories and methodologies, and the shown efficiency of the actions of prevention, this one acquires with evolving time a growing importance and a development desired with the eyes of the doctors, but also of the patients, policy decision makers and insurers. This article intends to approach and clarify the positive contributions but also the multiple limits of the preventive steps.

To construct French reference charts and equations for nuchal translucency thickness (NT) using a large sample of fetuses. To compare this new reference with previous ones.The study data were obtained from a single large screening center over seven years. Only measurements taken by trained and certified (Fetal Medicine Foundation) operators, with crown rump length (CRL) between of 45 to 84 mm were used. Multiple pregnancies, abnormal karyotype, cystic hygroma or measurements performed by operators performing less than 500 examinations over the study period were excluded. Raw centiles were computed for each CRL. They were then fitted using a least square regression model with high order polynomials. Predicted median values for NT were compared to previously published references and the impact of deviation in median NT was evaluated.There were 19,198 measurements included for NT modelling. New charts and equations for NT centiles calculations are reported. Median values were comparable to those reported in other populations. The small discrepancy in median NT did not impact on screening efficiency.We present new French reference charts and equations for NT at first trimester. These may serve as a basis for ongoing audit and quality control. Although they were derived from a very and unselected sample, they do not show clinically relevant difference as compared to existing references. Our results do no support the use or development of customized French reference charts and algorithm for first trimester screening.

To some, the subject of clinical prediction rules would seem an arcane exercise of limited utility to the everyday clinical anesthesiologist. Nothing could be further from the truth. Clinical prediction rules are plentiful and are in wideranging use in everyday practice. The American Society of Anesthesiologists’ physical status classification is one of the most widely used indices of preoperative physical status, and is easy to commit to memory. Thus, it has stood the test of time. Remarkably, it was introduced into everyday practice with little in the way of derivation, validation, or testing, yet it has been proven to perform as well as the Original (Goldman) Cardiac Risk Index, the Detsky Index, or the Revised Cardiac Risk Index. The Revised Cardiac Risk Index (RCRI) was derived from a cohort of 4,315 patients to predict the incidence of major cardiac morbidity in patients over the age of 50. In the validation set of 1,422 patients, the all-cause mortality doubled, due mostly to increased morbidity in the higher risk population, and the calibration of the index improved significantly. In addition, in the revised index, the coefficients of two risk factors identified from the validation set, diabetes and renal dysfunction, were subsequently found to no longer be significant. These observations highlight just a few of the issues involved with the application of clinical prediction rules. Despite the fact that the RCRI has been utilized in many cohort studies to risk-adjust patients, this index has yet to be externally validated. The performance of the RCRI was reported in a recent meta-analysis of 16 trials reporting on a total of 791,282 patients. This report found that the RCRI performs poorly (receiver operator characteristic [ROC] values of 0.630 compared to the original validation set value of 0.8). There are a number of reasons why the RCRI does not perform as well in ‘‘real life’’, including differences in the frequency of outcomes. In the derivation paper, the mortality was 1%, approximately half of that observed in the largest cohort study utilizing the RCRI, where the mortality rate was found to be 2%. Furthermore, there may have been different factors being applied. One factor in the derivation cohort was insulin-treated diabetes, which is now largely regarded as diabetes with or without insulin therapy. The original definition was renal dysfunction, defined as a serum creatinine concentration [176 mmol L. However, this definition has not been universally applied. Despite these important shortcomings, i.e., changes in the ROC between derivation and validation, the lack of external validation, or the findings that the RCRI loses accuracy when performed outside the original institution, the RCRI has been incorporated into the ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Non-cardiac Surgery. Thus, the RCRI has become an integral part of what now constitutes the ‘‘standard of care’’ for patients having non-cardiac surgery. Therefore, by default, any clinician involved in the evaluation of patients prior to non-cardiac surgery should have an understanding of the workings and limitations of this clinical prediction tool. Given the limitations of clinical prediction rules, the statement would also imply that the clinician should know the incidence of important outcomes and have the tools necessary to calibrate the instrument. P. M. A. Brasher, PhD (&) Centre for Clinical Epidemiology and Evaluation, VCH Research Institute, University of British Columbia, 828 West 10th Avenue, Vancouver, BC V5Z 1L8, Canada e-mail: brasher@interchange.ubc.ca

The cerebrospinal (CSF) infusion test is used to analyze the dynamics of CSF circulation. We describe the technique and report test results obtained in subjects with normal pressure hydrocephalus.The CSF infusion test is based on pressure monitoring during a continuous infusion of saline solution into the CSF space via a lumbar puncture. The main parameters are: intracranial pressure, resistance to CSF outflow (Rout), and compliance of the cranial enclosure estimated by the pressure-volume index. Our review of the recent literature dealing with the results of infusion test in normal pressure hydrocephalus indicates that the positive predictive value is about 80 % for Rout greater than 12 mmHg/ml per minute, i.e. shunt response is observed in 80 % of patients. The information available in the literature for assessing negative predictive value of Rout and usefulness of compliance is limited.The CSF infusion test may be helpful for the diagnosis of normal pressure hydrocephalus, as supplemental testing when the diagnosis is not certain. We propose a procedure, which includes the infusion test, for identifying shunt-responsive patients.

Researchers often use the Poisson regression model to analyze count data. Overdispersion can occur when a Poisson regression model is used, resulting in an underestimation of variance of the regression model parameters. Our objective was to take overdispersion into account and assess its impact with an illustration based on the data of a study investigating the relationship between use of the Internet to seek health information and number of primary care consultations.Three methods, overdispersed Poisson, a robust estimator, and negative binomial regression, were performed to take overdispersion into account in explaining variation in the number (Y) of primary care consultations. We tested overdispersion in the Poisson regression model using the ratio of the sum of Pearson residuals over the number of degrees of freedom (chi(2)/df). We then fitted the three models and compared parameter estimation to the estimations given by Poisson regression model.Variance of the number of primary care consultations (Var[Y]=21.03) was greater than the mean (E[Y]=5.93) and the chi(2)/df ratio was 3.26, which confirmed overdispersion. Standard errors of the parameters varied greatly between the Poisson regression model and the three other regression models. Interpretation of estimates from two variables (using the Internet to seek health information and single parent family) would have changed according to the model retained, with significant levels of 0.06 and 0.002 (Poisson), 0.29 and 0.09 (overdispersed Poisson), 0.29 and 0.13 (use of a robust estimator) and 0.45 and 0.13 (negative binomial) respectively.Different methods exist to solve the problem of underestimating variance in the Poisson regression model when overdispersion is present. The negative binomial regression model seems to be particularly accurate because of its theorical distribution ; in addition this regression is easy to perform with ordinary statistical software packages.

Meta-analysis of clinical trials allows all available quantitative evidence on therapeutic efficacy, to be condensed. Critical appraisal of all available evidence is a pillar of clinical science.

National audience; INTRODUCTION: In observational studies, a significant difference in the outcomes between treated and untreated patients may be observed in absence of treatment effect and caused by differences in baseline characteristics. EXEGESIS: Propensity score analysis is a post hoc adjustment method which consists in deriving the conditional probability of receiving the treatment for a patient given his measured baseline characteristics (i.e., the propensity score). Matching each treated patient to an untreated one who has the nearest propensity score tends to balance baseline characteristics between the two groups and reduce the risk for overt bias. Then, the outcomes can be compared between matched treated and untreated patients. CONCLUSION: Propensity score analysis is relevant for clinical conditions and treatments for which randomized controlled trials are unlikely to be conducted. However, propensity analysis cannot adjust for unmeasured characteristics and sensitivity analysis should be performed to assess how sensitive the conclusions are to potential confounding factors.

More and more frequently, the health authorities and the French assessment agencies are led to issue Marketing Authorizations (MAs), give opinions on the eligibility for reimbursement of drugs or to draft recommendations for clinical practice based on the results of foreign studies. The results of these studies are more or less difficult to transpose to French practice. These difficulties generate varying degrees of uncertainty concerning the effect to be expected of a drug. A more or less extensive loss of effect is sometimes even predictable. Some of the difficulties in transposition are discussed in this article and proposals for action are made in order to allow one, in the long term, to predict in the most precise manner possible the effects to be expected from a drug in the French population and be able to verify this prediction at an interval from its eligibility for reimbursement.

The influenza pandemic threat had led to an increased awareness and several countries have used models to assess the impact of control measures on the influenza pandemic. We reviewed the publications related to simulation models since 2003 and discuss their contribution to public health decision in France. The studies conclude that rapid control measures with a high coverage can stop a nascent pandemic. This can be applied to a community with a limited importation of cases but the quantity of antiviral drug needed would become rapidly prohibitive in case of further multiple foci. Both prophylactic and curative use of antiviral drugs can reduce the number of hospitalizations and the incidence during a pandemic. Finally, if a single strategy is sufficient to limit an outbreak in case of a moderate reproductive number, a combination of control measures is mandatory in case of highly transmissible strains. The results of these studies were taken in account to implement guidelines concerning antiviral drug use, in France.

Bayesian estimates of disease relative risks is currently the gold standard in disease mapping when the disease is rare and/or when the geographical area is small. Its use has become quite easy with adhoc software. However, the implicit mechanisms of the choices made by the user must be clearly identified. We were interested here in the consequences of the choice of the hyper a priori parameters. We have compared results obtained using various hyper a priori parameters. The consequences of these choices are illustrated through the example of the incidence of bladder cancer among men in the urban area of Grenoble. We show that the risks can appear weak from a statistical point of view but important from an epidemiologic point of view in the presentation of the results.

The boundary value (plateau) of non-periodic growth functions constitutes one of the parameters of various usual models such as the logistic equation. Its double interpretation involves either a limit of an internal or endogenous nature or an external environment-dependent limit. Using the autocatalytic model of structured cell populations (Buis, model II, 2003), a reformulation of the logistic equation is put forward and illustrated in the case of three cell classes (juvenile, mature, senescing). The agonistic component corresponds exactly to the only active fraction of the population (non-senescing mature cells), whereas the antagonistic component is interpreted in terms of an external limit (available substrate or source). The occurrence and properties of an external limit are investigated using the same autocatalytic model with two major modifications: the absence of competition (non-limiting source) and the occurrence of a maximum number of mitoses per cell filiation (Lück and Lück, 1978). The analysis, which is carried out according to the principle of deterministic cell automata (L-systems), shows the flexibility of the model, which exhibits a diversity of kinetic properties: shifts from the sigmoidal form, number and position of growth rate extremums, number of phases of the temporal structure. These characteristics correspond to the diversity of the experimental growth curves where the singularities of the growth rate gradient are often not accounted for satisfactorily by the usual global models.

Various statistical methods have been developed to describe spatial heterogeneity, in terms of high risk zones. If no source can be determined, this heterogeneity can be globally or locally described. Global methods test a statistic estimated over the whole studied geographical area, whereas local methods estimate a statistic on each spatial unit (or regrouping unit). This paper aimed to present, and to compare results of an epidemiological application, of five methods of spatial cluster detection.The two global detection methods were: 1) Moran's coefficient, a classically used autocorrelation coefficient; 2) Tango's statistic, a spatial generalization of the Chi(2) statistic. The three local methods were: 1) the local application of Moran's coefficient, proposed by Anselin; 2) the scan statistic, which searches for grouping of spatial units; 3) the oblique regression tree, which splits the studied zone into sub-zones of different risks. These five methods were applied to the description of the spatial heterogeneity of the malaria risk over a hyperendemic village, in Mali.All the methods highlighted a significant spatial heterogeneity. Both global methods (Moran's coefficient and Tango's statistic) showed weak spatial correlations. Local Moran's coefficient (with Bonferronis' adjustment) highlighted five spatial units. The scan statistic identified a single high risk cluster. The regression oblique tree split the study area into six sub-zones; the sub-zone with the higher risk was consistent with the cluster identified by the scan statistic.These presented methods do not require any previous knowledge of a source. They allow evaluating spatial risk heterogeneity over the entire geographical area under study. It is noteworthy that shape, size, and spatial heterogeneity characteristics (either global or local) of the study area, as well as the definition of the proximity, significantly influence the spatial risk analysis' outcome. Although their results should be cautiously interpreted, these methods are useful for preliminary field studies or epidemiological surveys.

Colorectal cancer (CRC) screening in France is based on a faecal occult blood test every two years in average risk subjects 50-74 years of age while other endoscopic or non-endoscopic screening methods are used in Europe and in the USA. Beside the reduced incidence of and mortality from CRC found in available studies, cost-effectiveness data need to be taken into account. Because of the delay between randomized controlled trials and clinical results, transitional probabilistic models of screening programs are useful for public health policy makers. The aim of the present review was to promote the implementation of cost-effectiveness studies, to provide a guide to analyze cost-effectiveness studies on CRC screening and, to propose a French cost effectiveness study comparing CRC screening strategies. Most of these trials were performed by US or UK authors and demonstrate that the incremental cost-effectiveness ratio varies between 5 000 and 15 000 US dollars/one year life gained, with wide variations: these results were highly dependent on the unit costs of the different devices as well as the predictive values of the screening tests. Although CRC screening programs have been implemented in several administrative districts of France since 2002, and the results of these randomized controlled trials using fecal occult blood have been updated, cost-effectiveness criteria need to be integrated; especially since the results of screening campaigns based on other tools such as flexible sigmoidoscopy should be available in 2007.

When the sensitivity of an assay used to quantify a marker is poor, some of the values are below the detection limit resulting in left-censoring. Analysis of such data requires appropriate statistical techniques. In this study, we aimed at comparing various methods used to deal with left-censored outcome in regression analysis.The application was a real study evaluating the performance of procalcitonin for the diagnosis of bacterial infections among elderly patients. Among 85 patients, eleven had a procalcitonin value below the detection limit. A simulation study was then performed with data sampled according to a Gaussian distribution with parameters estimated on observed data. Various levels of left-censoring were simulated (13, 25 and 50%). A linear regression model was used to explain procalcitonin variations according to another marker, C reactive protein. To handle left-censoring, several methods were used: complete case analysis, simple imputation and multiple imputation methods, and parametric modelling. In the simulation study, estimations according to different methods were compared in terms of bias and mean square error according to each left-censoring level. Estimations obtained with real data were also compared according to the methods used. All analyses were implemented using SAS software.In the simulation study, parametric modelling using maximum likelihood showed best performances whatever the level of censoring. On the other hand, methods using complete cases and simple imputation by the detection limit were highly skewed. On observed data, estimations of the slope varied slightly according to the methods. However the p-values (Wald test) of beta=0 varied from 0.0001 to 0.13 leading to different decisions according to the method used.Left-censoring handling in data analysis requires special attention, as different methods may yield results leading to different conclusions.

To characterize and investigate the higher-order optical aberrations (HOAs) and their distribution and symmetry between both eyes (enantiomorphism).Wave-front measurements were taken using Hartmann-Shack aberrometry and Zernike polynomial terms reconstruction of the total ocular wave front. Optical aberrations were quantitatively analyzed using the RMS (root mean square) Zernike coefficient term value. Symmetry between both eyes was assessed for each aberration according to two criteria: the RMS coefficient value and aberration magnitude.Sixty patients were included in the study. The HOAs presenting the highest magnitude were fourth-order spherical aberration (Z40; M=0.3038 microm), primary coma (Z31; magnitude M=0.2285 microm) and trefoil (Z33; M=0.1870 microm). A significant mirror symmetry between both eyes was present for high-order aberration orientations. Considering the magnitude of each aberration, symmetry was present in seven of eight aberrations (all but primary coma). HOAs were higher for ametropes than emmetropes. The hyperoptic eyes had more spherical aberrations than myopic and emmetropic eyes.Symmetry between the right and left eye is a less common characteristic of HOAs. The difference in the mean age of the studied population may account for the differences in the total high-order and spherical aberration levels found in our study.

The numerical method commonly used as an help to the bacterian identification appears quite efficient in its first role, i.e. to propose the name of the plausible bacteria, but it fails to define a confidence level to be assiociated to the final decision. To correct this, this paper propose to calculate the response probability distribution for each possible bacteria. The calculation uses the so-called "Monte-Carlo" method and has to be performed once for all on a given set of biochemical tests. For each calculated ditribution, it is easy to find a first kind error risk, or alpha-error risk. The proposed theoretical approach moreover avoid the comparison of "identification scores", which is always questionable so far the various bacteria present very different sensitivities to the biochemical tests.