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Cost and effectiveness are usually modeled according to one studied event or one health state with parametric or non-parametric methods. In this paper, we propose an original method for assessing total costs while incorporating the dynamics of change in the health status of patients. A semi-Markov model in which the distributions of sojourn times are explicitly defined is developed. The hazard function of sojourn times is modeled by Weibull distributions specific to each transition. A vector of covariates is incorporated into the hazard function of each transition. From a regression model for costs, a cumulative cost function is derived. An estimation of the mean cost per patient in each state defined in the semi-Markov model could thus be made, and this enables us to identify the determinants of direct costs. The results of incremental net benefit (INB) are assessed using the bootstrap method. A cost-effectiveness analysis is performed in order to compare two strategies of follow-up in the colorectal cancer study. Two hundred and forty patients were enrolled in this study. Three health states are defined for patients with curative resection of colorectal cancer: alive without relapse, alive with relapse, and dead. The mean survival is 4.35 and 4.12 years, respectively, in the standard and moderate follow-up groups. We show that mean cost differs significantly by follow-up strategy and Dukes stage. Finally, the INB is assessed and this indicates that neither of the strategies compared was more cost-effective than the other., (Copyright (c) 2007 John Wiley & Sons, Ltd.)

An evaluation process directed by the biochemistry department of the UHC of Montpellier about acquisition of blood gas analysers for a point of care testing in 10 different medical care services. The values obtained by the different measurement machines have been compared taking into account the intra and inter measures variabilities. In this work, the results of 4 machines tested: Rapid-point 405, GEM Premier 3000, i-STAT 1 (série 300) and ABL 77 are compared with one i-STAT (série 200) and one OMNI S already available in the laboratory. The study lasted one month (november 2004). Each week, the two machines of the laboratory was compared with a new analyser randomly chosen between the four machines tested. In this study, including 21000 values, the statistical tests have been applied under the hypothesis that none of the measurement machine could be a "gold standard". Beside the classical research of correlation between the different values, we added the research of concordance between machines and the application of imperfect gold standard method. A high level of statistic concordance was observed between the different analysers. So the equipment has been selected using biological, analytic and computing criteria.

Objective: We sought to evaluate the use of oligonucleotide arrays to discriminate colonization from infection due to Staphylococcus aureus in diabetic foot ulcers., Research Design and Methods: We included diabetic patients hospitalized in a diabetic foot department for an episode of foot ulcer. Only patients who had no antibiotic treatment during the previous 6 months were included. At admission, ulcers were classified on clinical examination, according to the Infectious Diseases Society of America system. Seventy-two patients with a culture positive only for S. aureus as the sole pathogen were included. In individuals with a grade 1 ulcer, a second wound bacterial specimen was obtained 1 month later. Using oligonucleotide arrays, S. aureus resistance and virulence genes were compared between grade 1 and grades 2-4 ulcers., Results: S. aureus was initially isolated from 22 grade 1 and 50 grade 2-4 ulcers: 35 were methicillin resistant and 37 methicillin sensitive. In 20 grade 1 ulcers (92%), no virulence genes were identified, whereas these genes were present in all but 1 grade 2-4 ulcers. During follow-up, the two grade 1 ulcers that were infected with strains carrying virulence genes rapidly deteriorated; the array technology showed unchanged genotype profiles. On the contrary, two grade 1 ulcers healed: the genotype profiles were different from those at inclusion but without appearance of virulence genes., Conclusions: The DNA array appears as a promising technique and is easy to perform. Our observational study suggests that it might help distinguish colonized grade 1 from infected grade 2 wounds, predict ulcer outcome, and contribute to a more adequate use of antibiotics.

Background: The allergic rhinitis and its impact on asthma (ARIA) guidelines provide a new classification of allergic rhinitis, but a quantitative analysis for severity assessment is lacking., Objective: To study whether a visual analog scale (VAS) for global rhinitis symptoms could be used to assess the disease severity according to ARIA., Methods: Three thousand fifty-two allergic rhinitis patients seen in primary care were tested. Fifty three per cent had an objective diagnosis of allergy and 58% of the patients were treated. Patients were categorized according to ARIA guidelines. The severity of nasal symptoms was assessed using a VAS. Quality of life was measured using the rhinoconjunctivitis quality of life questionnaire (RQLQ)., Results: Severity had more impact on VAS levels than duration: mild intermittent rhinitis (3.5, 2.4-5.0 cm), mild persistent rhinitis (4.5, 3.2-5.6 cm), moderate/severe intermittent rhinitis (6.7, 5.3-7.7 cm) and moderate/severe persistent rhinitis (7.2, 6.1-8.2 cm). The receiver operating characteristic curve results showed that patients with a VAS of under 5 cm could be classified as 'mild' rhinitis (negative predictive value: 93.5%) and those with a VAS of over 6 cm as 'moderate/severe' rhinitis (positive predictive value: 73.6%). Receiver operating characteristic curves and a logistic regression showed that current treatment and allergy diagnosis have no effect on the assessment of rhinitis severity using VAS. Visual analog scale and the RQLQ global score were significantly correlated (rho = 0.46; P < 0.0001)., Conclusion: A simple and quantitative method (VAS) can be used for the quantitative evaluation of severity of allergic rhinitis.

Cost of illness (COI) studies estimate the overall economic burden of a specific disease, rather than simply treatment-related costs. While having been criticised for not allowing resource prioritisation, COI studies can provide useful guidance, so long as they adhere to accepted methodology. The aim of this review is to analyse the methods used to evaluate the cost of lung cancer. Because of the increasing incidence and high direct and indirect costs of lung cancer, it is an important disease in terms of economic implications, and therefore provides a relevant example with which to review COI study methodologies. First, the key points of the methodology relating to COI studies were identified. COI studies relating to lung cancer were then reviewed, focussing on an analysis of the different methods used and an identification of the strengths and weaknesses of each approach. The COI studies that were analysed confirmed that lung cancer is a costly illness, and that hospitalisation and treatments account for a large part of direct costs, while indirect costs represent a large part of the total costs. The review also showed that COI studies adopted significantly different approaches to estimate the costs of lung cancer, reflecting a lack of consensus on the methodology of COI studies in this area. Hence, to increase the credibility of COI studies, closer agreement among researchers on methodological principles would be desirable.

Introduction: To evaluate the average cost of therapeutic strategies for the management of lung cancer in relation to histological type and diagnostic staging and of the individual components of the management strategy., Methods: Samples were taken between 1 September 1998 and 30 June 1999 from centres with sufficient numbers of lung cancer (LC) cases. All events over an 18 Month period were collected from a retrospective analysis of the records. A Markov model was constructed based on decision branches for localised and diffuse small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Several components of management were identified: first line treatment, second line treatment, observation, terminal care and death., Results: The average cost of LC was 22,006 Euro (10,631-36,296) for one year and 25,643 Euro (10,631-46,191) for two years. For SCLC the average annual costs were 22,420 Euro for diffuse disease and 27,098 for localised disease. For NSCLC the totals ranged from 19,543 Euro for inoperable stage I and II tumours to 39,424 for operable tumours. The cost for stage IV tumours was 24,383 Euro. The cost components over two Years varied according to the tumour type. The cost of diagnosis ranged from 6-14%, the cost of management and of terminal care from 33-45% of the total. Analyses of sensitivity confirmed that whatever the histological type or diagnostic staging the percentage of patients initially treated actively (that is to say not by palliative care) had the greatest effect on the total cost, greater than the costs of terminal care and of two courses of chemotherapy., Conclusions: This model has allowed for the first time the calculation of the contributions of the different therapeutic components to the total cost of the management of lung cancer in France. In the future it will allow analysis of the economic impact of new methods of treatment.

The follow-up of patients with curative resection of colorectal cancer is still controversial. The means mobilized for postoperative monitoring come at a high cost. However, the modalities are neither formalized nor validated with regard to an improved 5-year survival rate. To compare the cost-effectiveness of both strategies for patient follow-up during the 7 years following curative resection of colorectal cancer, we performed a costeffectiveness analysis adjusted for quality of life. Using data from the literature and a population study, a simulation of follow-up on patients who had undergone curative resection of colorectal cancer was carried out over a 7-year period using a Markov model. Two Markov processes were modeled to compare the cost-effectiveness ratio adjusted for quality of life in patients with a follow-up in accordance with the recommendations of the 1998 French Consensus Conference (standard follow-up) with the carcinoembryonic antigen (CEA) assay and a simplified follow-up. The influence of standard follow-up on the quality-adjusted life expectancy of patients who had Duke's stage A and B colorectal cancer appears to be modest, with increases of 2.5 months and 1.3 months, respectively; it is more acceptable for patients who had had Duke's stage C, with an increase of 11 months. The high variability of cost-effectiveness ratios (> 7 years) of +/- 44,830 and 180,195 Euro per quality-adjusted life-years (QALY), respectively) did not favor the standard follow-up. The cost-effectiveness ratio (> 7 years) of patients having had Duke's stage C colorectal cancer was 1,058 (sd: 2746) Euro per QALY and could favor the standard follow-up. This study showed that standard follow-up with CEA assay tended to preferentially improve the survival of Duke's stage C patients. The type of examination needed and the frequency with which it has to be carried out should take account of the stage, treatment for the initial illness, and the patient's age.

Control and severity of asthma are two different but complementary concepts. The severity of asthma could influence the control over time. The aim of this study was to demonstrate this relationship. A total 365 patients with persistent asthma (severity) were enrolled and followed-up prospectively. Data were analysed using a continuous time homogeneous Markov model of the natural history of asthma. Control of asthma was defined according to three health states which were qualified: optimal, suboptimal and unacceptable control (states 1, 2 and 3). Transition forces (denoted lambda(ij) from state i to state j) and transition probabilities between control states were assessed and the results stratified by asthma severity were compared. Models were validated by comparing expected and observed numbers of patients in the different states. Transition probabilities stabilised between 100-250 days and more rapidly in patients with mild-to-moderate asthma. Patients with mild-to-moderate asthma in suboptimal or unacceptable control had a high probability of transition directly to optimal control. Patients with severe asthma had a tendency to remain in unacceptable control. A Markov model is a useful tool to model the control of asthma over time. Severity modified clearly the health states. It could be used to compare the performance of different approaches to asthma management.

Background: Alcoholism is a worldwide problem. Many strategies for alcohol detoxification and relapse prevention exist, but each alcohol treatment center has its own program. The objective of this study was to analyze and compare the financial cost and effectiveness of alcohol treatment programs from inpatient stay to follow-up 1 year later. This was a prospective, open, nonrandomized study of 4 specialized alcohol treatment centers and 267 patients admitted for alcohol detoxification., Methods: We recorded all medical and nonmedical interventions related to the program during patient stay in the hospital and every 3 months after discharge for 1 year and recorded the occurrence of alcohol relapse. Financial evaluation was based on the prices of refund from the French national health insurance service., Results: The mean cost of hospitalization ranged from 1326 euros to 1917 euros(p = 0.001), a variation mainly due to the difference in the length of hospital stay but also to the cost of the inpatient program, routine medical checkups, and drugs administered. The mean cost of 1 year of follow-up per patient ranged from 419 euros to 1704 euros (p = 0.001). The efficiency, corresponding to the money spent to prevent the relapse of one patient during 1 month, was approximately 500 euros/month in three centers and 658 euros in the fourth. However, for a similar efficiency, the effectiveness, assessed by the mean time without relapse, was significantly (p = 0.001) different; center 1, which had the highest total cost, had an effectiveness 1.56 times higher than center 3, which had the lowest cost., Conclusions: This work emphasizes the heterogeneity of the costs and effectiveness of alcoholism treatment programs and suggests that research should be conducted to determine which program is the most rational, cost-efficient, and beneficial for patients and the public health office economy.