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A goal of asthma management is to improve the patient's health-related quality of life (HRQL). However, it is unclear whether HRQL instruments can discriminate across asthma control measures. The objective of this study was to evaluate the validity of generic and condition-specific preference-based instruments, in terms of their ability to distinguish asthma control.Asthma patients (n = 157) completed three generic preference-based instruments: the Health Utility Index Mark 3 (HUI-3), the EuroQol (EQ-5D), and the Short Form 6D (SF-6D) and two condition-specific questionnaires: the standardized Asthma Quality of Life Questionnaire (AQLQ(S)) and the Asthma Control Questionnaire (ACQ). The AQLQ(S) scores were converted into the condition-specific preference-based scores: the Asthma Quality of Life Utility Index (AQL-5D).The preference-based instruments were generally able to discriminate across control measures, such as ACQ scores and magnitude of asthma medication, but were not able to discriminate for self-reported control and severity levels. These instruments also correlated with most control measures (r = 0.32-0.37). Significant relationships between AQL-5D scores and all control variables were observed.Overall, the AQL-5D discriminated across all levels of asthma control. The HUI-3, the EQ-5D, and the SF-6D differentiated between the highest and lowest levels of control but could not discriminate between the moderate levels.

Background: Patient self-management of long-term oral anticoagulation therapy is an effective strategy in a number of clinical situations, but it is currently not a funded option in the Canadian health care system. We sought to compare the incremental cost and health benefits of self-management with those of physician management from the perspective of the Canadian health care payer over a 5-year period. Methods: We developed a Bayesian Markov model comparing the costs and quality-adjusted life years (QALYs) accrued to patients receiving oral anticoagulation therapy through self-management or physician management for atrial fibrillation or for a mechanical heart valve. Five health states were defined: no events, minor hemorrhagic events, major hemorrhagic events, thrombotic events and death. Data from published literature were used for transition probabilities. Canadian 2003 costs were used, and utility estimates were obtained from various published sources. Results: Self-management resulted in 3.50 fewer thrombotic events, 0.78 fewer major hemorrhagic events and 0.12 fewer deaths per 100 patients than physician management. The average discounted incremental cost of self-management over physician management was found to be $989 (95% confidence interval [CI] $310‐$1655) per patient and the incremental QALYs gained was 0.07 (95% CI 0.06‐0.08). The cost-effectiveness of self-management was $14 129 per QALY gained. There was a 95% chance that self-management would be cost-effective at a willingness to pay of $23 800 per QALY. Results were robust in probabilistic and deterministic sensitivity analyses. Interpretation: This model suggests that self-management is a cost-effective strategy for those receiving long-term oral anticoagulation therapy for atrial fibrillation or for a mechanical heart valve.

Emergency contraception[1][1] is just the latest example in a long list of medications that are being shifted from prescription only to over-the-counter (OTC) status. More experience with other potent and effective prescription drugs and an increased understanding of their safety and efficacy in the

The present clinical use of serum osmometry is erroneous in two respects. The first, and the most important, is the incorrect assumption that serum behaves as a dilute 'ideal' solution and that the osmotic activity of a substance depends solely on the number of solute particles. The amount of variance from ideal behaviour of serum containing an exogenous substance is expressed by the osmotic coefficient (phi). We have calculated the osmotic coefficient for serum containing ethanol (alcohol) and recommend that the osmotic coefficient for serum containing other low molecular weight substances such as methanol (methyl alcohol), isopropyl alcohol and ethylene glycol also be calculated. This is necessary for the accurate calculation of the contribution of these substances to the serum osmolality.Secondly, the practice of subtracting the calculated serum molarity from measured serum osmolality is not valid since it represents a mathematically improper expression. The units of these two terms are different. The 'osmole gap' (OG) is typically viewed as the difference between serum osmolality determined by an osmometer and the estimated total molarity of solute in serum by directly measuring the concentration of several substances and then substituting them into a published formula. Some authors call this sum the calculated or estimated osmolarity but, because the concentrations are measured directly and not with an osmometer, the calculated term represents molarity. The units of osmolality are mmol/kg of H2O and the units of molarity are mmol/L. Therefore, the practice of subtracting calculated serum molarity from measured serum osmolality is not mathematically sound and is an oversimplification for ease of application. This mathematical transgression necessarily adds an error to the incorrectly calculated OG. Despite this, the OG is commonly used in clinical medicine. Serum osmolality can be converted to molarity provided the weight percentage and the density of the solution are known and thus, we recommend that this conversion be done prior to calculation of the gap. We recommend that the gap between measured serum osmolarity and calculated serum molarity be called the 'osmolar gap'. After having corrected for non-ideality for serum and for inconsistency of units, the standard value and reference range for this gap must be determined in an adequate number of patient populations and in a variety of clinical settings. An example of this determination, using data from a group of ethanol-poisoned patients is given. This correction should be applied before the evaluation of the osmolar gap as a screening test for other low molecular weight substances proceeds.

The rapid and accurate diagnosis of toxic alcohol poisoning due to methanol (methyl alcohol) [MeOH] and ethylene glycol (EG), is paramount in preventing serious adverse outcomes. The quantitative measurement of specific serum levels of these substances using gas chromatography is expensive, time consuming and generally only available at major tertiary-care facilities. Therefore, because these toxic substances are osmotically active and the measurement of serum osmolality is easily performed and more readily available, the presence of an osmole gap (OG) has been adopted as an alternative screening test. By definition, the OG is the difference between the measured serum osmolality determined using the freezing point depression (Osm(m)) and the calculated serum molarity (Mc), which is estimated from the known and readily measurable osmotically active substances in the serum, in particular sodium, urea, glucose, and potassium and ethanol (alcohol). Thus, the OG=Osm(m)-Mc, and an OG above a specific threshold (the threshold of positivity) suggests the presence of unmeasured osmotically active substances, which could be indicative of a toxic exposure. The objectives of this study were to review the principles of evaluating screening tests, the theory behind the OG as a screening test and the literature upon which the adoption of the OG as a screening test has been based. This review revealed that there have been numerous equations derived and proposed for the estimation of the Mc, with the objective of developing empirical evidence of the best equation for the determination of the OG and ultimately the utility of OG as a screening test. However, the methods and statistical analysis employed have generally been inconsistent with recommended guidelines for screening test evaluation and although many equations have been derived, they have not been appropriately validated. Specific evidence of the clinical utility of the OG requires that a threshold of positivity be definitively established, and the sensitivity and specificity of the OG in patients exposed to either EG or MeOH be measured. However, the majority of studies to date have only evaluated the relationship between the Osm(m) (mmol/kg H2O) and the Mc (mmol/L) in patients that have not been exposed to either MeOH or EG. While some studies have evaluated the relationship between the OG and serum ethanol concentration, these findings cannot be extrapolated to the use of the OG to screen for toxic alcohol exposure. This review shows that there has not been an appropriately designed empirical evaluation of the diagnostic utility of the OG and that its clinical utility remains hypothetical, having been theoretically extrapolated from the non-poisoned population.

The growing number of multinational clinical trials in which patient-level health care resource data are collected have raised the issue of which is the best approach for making inference for individual countries with respect to the between-treatment difference in mean cost. We describe and discuss the relative merits of three approaches. The first uses the random effects pooled estimate from all countries to estimate the difference for any particular country. The second approach estimates the difference using only the data from the specific country in question. Using empirical Bayes estimation a third approach estimates the country-specific difference using a variance-weighted linear sum of the estimates provided by the other two approaches. The approaches are illustrated and compared using the data from the ASSENT-3 trial.

To assess the association between socioeconomic status (SES) and short-acting (SA) beta-agonist use, controlling for asthma severity.Cross-sectional study.Vancouver, BC, Canada.Two hundred two asthmatics between 19 years and 50 years of age and residing in the greater Vancouver regional district.The quantity of SA beta-agonist used in the previous year was collected by self-report; pulmonary function and beta-receptor genotype were measured on each participant. SES was measured at both the individual and population levels. Five methods of adjustment for asthma severity were used, as follows: the Canadian Asthma Consensus Guidelines, three previously developed asthma-severity scores, and forward stepwise multiple regression modeling. Polychotomous logistic regression was used to assess all relationships.Independent of the method used to measure SES or adjust for asthma severity, lower SES was consistently and significantly associated with the use of greater amounts of SA beta-agonist. Adjusting for severity using the multivariate model explained the most variance of SA beta-agonist use (R(2) adjusted, 0.35 to 0.37). In this model, social assistance recipients were more likely to use greater amounts of SA beta-agonist (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.7 to 6.5). An inverse relationship between SA beta-agonist use and both annual household income ($50,000; OR, 0.28; 95% CI, 0.13 to 0.60; and $20,000 to $50,000; OR, 0.44; 95% CI, 0.21 to 0.96; relative to$20,000) and education (completing a bachelor's degree vs no formal education; OR, 0.25; 95% CI, 0.14 to 0.71). Participants living in a neighborhood with higher median household income (OR, 0.91; 95% CI, 0.84 to 0.98 per $1,000 increase) or a higher prevalence of having attained a bachelor's degree (OR, 0.96; 95% CI, 0.84 to 0.98 per 1% increase) were also less likely use greater amounts of SA beta-agonist. Results were consistent for neighborhood unemployment rate.The social gradient in asthma-related outcomes may be at least partially attributable to poorer asthma control in lower-SES asthmatics.

Objective To demonstrate the use of probabilistic simulation modeling to estimate the joint density of therapeutic risks and benefits. Published data are used to introduce the risk–benefit acceptability curve as a novel method of illustrating risk–benefit analysis. Study design and setting Using published data, we performed a second-order Monte Carlo simulation to estimate the joint density of major bleeding and deep vein thrombosis (DVT) secondary to enoxaparin or unfractionated heparin. Within a Bayesian framework, beta-distributions for the probabilities of experiencing a DVT and major bleed were derived from the clinical trial, and incremental probabilities were calculated. Results The incremental risk–benefit pairs from 3,000 simulations are presented on a risk–benefit plane. To accommodate different risk preferences, the results are also illustrated using a risk–benefit acceptability curve, which incorporates different risk–benefit acceptability thresholds (μ), or the number of major bleeds one is willing to accept in order to avert one DVT. Finally, a net-benefit curve is used to illustrate the risk–benefit ratio and the derivation of 95% confidence intervals around the ratio. Conclusion Modern simulation methods permit the estimation of the joint density of risks and benefits with their associated uncertainty, and within a Bayesian framework, facilitate the estimation of the probability that a therapy is net-beneficial over different preference thresholds for risk–benefit trade-offs.

Introduction: Implantable cardioverter defibrillator (ICD) therapy is indicated for patients at risk for sudden cardiac death (SCD) due to ventricular tachycardia (VT) or ventricular fibrillation (VF). The high relative cost of therapy with the ICD versus antiarrhythmic drugs has raised questions regarding its cost-effectiveness. To address these questions, we review the literature on ICD cost-effectiveness. Methods and Results: MEDLINE and other databases were searched for articles published since 1980 reporting original data on the cost-effectiveness of ICD versus drug therapy for patients at risk for SCD. Data on costs and life-years were abstracted and studies grouped into decision analysis models and trial-based analyses. Cost-effectiveness ratios were inflated to 2002 US dollars. Thirteen economic studies were included in this review: 6 decision-analytic models, 4 economic analysis alongside randomized controlled trials, and 1 observational study. Two additional studies evaluated the cost-effectiveness of ICDs stratified by mortality risk. Studies varied in time horizon, and in all but one study ICD therapy was more costly than drug therapy. Early models assumed larger survival benefits than were observed in subsequent trials; therefore, ICDs appeared to be more cost-effective (i.e., $28,000–$60,000 per life-year gained). Three large clinical trial-based studies estimated that the cost per life-year gained was between $30,181 and $185,000. Stratified analyses show that patients at higher risk for mortality due to structural heart disease (e.g., left ventricular ejection fraction

To assess trends in asthma management and to identify factors associated with increasing short-acting (SA) beta-agonist utilization in British Columbia using administrative prescription data.A retrospective cohort analysis.All patients between 13 and 50 years of age who had received at least one prescription for a SA beta-agonist covered by BC Pharmacare between January 1, 1996, and December 31, 1998.Cross-sectional analysis of all patients, and longitudinal analyses only of patients who had received at least one SA beta-agonist prescription in each of the 3 years. Trends in asthma medication use over time were evaluated using repeated-measures Mantel-Haenszel tests. Multiple logistic regression was used to identify factors associated with increasing SA beta-agonist use.A total of 78,758 patients were included in the cohort. No decrease in the annual prevalence of receiving more than four canisters per year of a SA beta-agonist was identified between 1996 and 1998. A total of 12,844 patients filled at least one SA beta-agonist prescription each year. Time-trend analysis showed an overall increasing probability of not receiving an inhaled corticosteroid (ICS) agent in this population (p = 0.002). In patients exhibiting low SA beta-agonist use,18 years of age (adjusted odds ratio [OR], 1.5), male gender (adjusted OR, 1.7), and in receipt of social assistance (adjusted OR, 2.3) were associated with receiving increasing amounts of SA beta-agonist agents over the 3 years. In patients with a high degree of use of SA beta-agonists, only the receipt of social assistance (adjusted OR, 1.3) was significantly associated with increasing use.Despite the development and dissemination of asthma management guidelines, there was no trend toward decreasing SA beta-agonist use. An unexpected trend toward decreasing ICS utilization was identified. Receiving social assistance was a risk factor for increasing SA beta-agonist use, independent of baseline utilization.

Background: Patient decision aids (PtDA) are developed to facilitate informed, value-based decisions about health. Research suggests that even when informed with necessary evidence and information, cognitive errors can prevent patients from choosing the option that is most congruent with their own values. We sought to utilize principles of behavioural economics to develop a computer application that presents information from conventional decision aids in a way that reduces these errors, subsequently promoting higher quality decisions. Method: The Dynamic Computer Interactive Decision Application (DCIDA) was developed to target four common errors that can impede quality decision making with PtDAs: unstable values, order effects, overweighting of rare events, and information overload. Healthy volunteers were recruited to an interview to use three PtDAs converted to the DCIDA on a computer equipped with an eye tracker. Participants were first used a conventional PtDA, and then subsequently used the DCIDA version. User testing was assessed based on whether respondents found the software both usable: evaluated using a) eye-tracking, b) the system usability scale, and c) user verbal responses from a ‘think aloud’ protocol; and useful: evaluated using a) eye-tracking, b) whether preferences for options were changed, and c) and the decisional conflict scale. Results: Of the 20 participants recruited to the study, 11 were male (55%), the mean age was 35, 18 had at least a high school education (90%), and 8 (40%) had a college or university degree. Eye-tracking results, alongside a mean system usability scale score of 73 (range 68–85), indicated a reasonable degree of usability for the DCIDA. The think aloud study suggested areas for further improvement. The DCIDA also appeared to be useful to participants wherein subjects focused more on the features of the decision that were most important to them (21% increase in time spent focusing on the most important feature). Seven subjects (25%) changed their preferred option when using DCIDA. Conclusion: Preliminary results suggest that DCIDA has potential to improve the quality of patient decision-making. Next steps include larger studies to test individual components of DCIDA and feasibility testing with patients making real decisions.

Background: Post-hospital syndrome refers to the period of generalized risk of adverse health outcomes among patients who are recently discharged from hospital. This period is associated with a short-term increased risk of readmission which may not be related to the original condition. While the majority of studies of post-hospital syndrome have focused on all-cause readmissions, whether and to what extent such a phenomenon exists within discrete medical conditions is not yet known. Objective: To investigate whether the risk of admission due to asthma is increased in individuals who are discharged following any-cause hospital admission. Methods: Using administrative health data for the period 1997 to 2007 from the province of British Columbia, Canada, we created a cohort of adults with asthma. Using a case-crossover design, we assessed the association between discharge from a hospital (exposure) within 30 days before an asthma-related hospitalization (the outcome), using two 30-day control periods within the same subject. Conditional logistic regression was performed to calculate the relative risk (RR) of the outcome in association with exposure. We performed several sensitivity and subgroup analyses. Results: The final cohort included 3,852 patients experiencing 6,333 instances of the outcome. Mean age at the time of the outcome was 43.7 (SD 14.2), 69.0% of such outcomes belonged to females. The RR of the outcome within the next 30 days of a previous any-cause discharge was 1.40 (95% CI 1.22 - 1.59). However, the association was mainly caused by discharge from asthma-related admission [RR = 1.99 (95% CI 1.65 - 2.39)]. The RR associated with non-asthma-related discharge was 0.88 (95% CI 0.74 - 1.04) and was not statistically significant. Similar results were obtained in a range of sensitivity analyses. Discussion: Our results indicate that in patients with asthma, the 30-day risk of asthma-related admission is increased after an episode of asthma-related hospitalization, but not after an episode of non-asthma-related hospitalization.

OBJECTIVE To determine the risk for serotonin syndrome associated with the concomitant use of sumatriptan and the currently contraindicated therapies, that is, the monoamine oxidase inhibitors (MAOIs), serotonin selective-reuptake inhibitors (SSRIs), and lithium. METHODOLOGY: A comprehensive search for reports of serotonin syndrome associated with sumatriptan use was conducted by using tertiary drug interaction literature, MEDLINE, EmBASE, Biological Abstracts, Current Contents, Reactions, ClinAlert, and the International Pharmaceutical Abstracts. In addition, related reports from the proprietary manufacturers, the Health Protection Branch of Health Canada, and the World Health Organization Collaborative Centre for International Drug Monitoring were also solicited. RESULTS The concurrent use of sumatriptan with an SSRI or lithium has been reported to cause symptoms suggestive of serotonin syndrome in 16 and 2 cases, respectively. There were no reports involving MAOIs. In general, the reports indicated a mild-to-moderate, self-limited course with some features consistent with the serotonin syndrome. We found published reports of sumatriptan use without adverse events involving 148 patients receiving SSRIs, 31 patients taking MAOIs, and a small number using lithium. CONCLUSIONS Clinical evidence supporting the strict contraindication of MAOIs, SSRIs, and lithium was not identified. The balance of documented clinical experience pertaining to the use of sumatriptan concurrently with SSRIs or lithium suggests that most patients tolerate this combination without incident. Because there is little reliable experience with sumatriptan in combination with MAOIs, we suggest that sumatriptan should continue to be avoided in patients taking these agents until further data demonstrating safety become available. OBJETIVO Determinar el riego de desarrollar el síndrome de la serotonina asociado al uso concomitante del sumatriptan con agentes inhibidores selectivos de la captura de la serotonina, inhibidores de la monoamina oxidasa (IMAO), y el litio. MÉTODOS Las fuentes de información incluyeron la literatura de interacciones medicamentosas, MEDLINE, EmBASE, Biological Abstracts, Current Contents, Reactions, ClinAlert, y International Pharmaceutical Abstracts. También reportes emanados por los fabricantes de estos medicamentos, la Rama de Protección de la Salud de Salud Canada, y el Centro Colaborativo de Monitoreo Internacional de Medicamentos de la Organización Mundial de la Salud. RESULTADOS Los resultados de la investigación sugieren la presencia del síndrome de la serotonina en 16 casos de pacientes que recibieron el sumatriptan con los inhibidores selectivos de la captura de la serotonina y en 2 casos de pacientes que recibieron el sumatriptan con el litio. No hubo reportes que involucrasen a los IMAO. Las manifestaciones clínicas de este síndrome están descritas en este artículo. En general, los reportes indican que el curso de este evento es de leve a moderado y auto limitante. Los autores consiguieron un número considerable de reportes de estas combinaciones que no condujeron a reacciones adversas. Estos incluyeron 148 reportes del uso del sumatriptan con inhibidores selectivos de la captura de la serotonina, 31 del uso del sumatriptan con IMAO, y un número pequeño del uso del sumatriptan con el litio. CONCLUSIONES No existe suficiente evidencia clínica de que los IMAO, los inhibidores selectivos de la captura de la serotonina o que el litio estén totalmente contraindicados en pacientes recibiendo el sumatriptan. La experiencia clínica documentada hasta el presente sugiere que la mayoría de los pacientes toleran esta combinación sin incidentes. Debido a que existe poca experiencia acerca del uso del sumatriptan con los IMAO, los autores sugieren que esta combinación sea evitada hasta que haya mayor información sobre su seguridad. OBJECTIF Préciser le risque d'apparition d'un syndrome sérotoninergique lié à l'emploi concomitant de sumatriptan et des inhibiteurs de la monoamine oxydase (IMAO), des inhibiteurs sélectifs de la recapture de la sérotonine (ISRS), ou du lithium. MÉTHODES Une recherche des rapports publiés sur le syndrome sérotoninergique lié à l'emploi du sumatriptan a été menée dans les sources d'informations spécialisées en interactions médicamenteuses, dans les banques informatisées MEDLINE et EmBASE, dans les revues Biological Abstracts, Current Contents, Reactions, ClinAlert, et International Pharmaceutical Abstracts. De plus, les données des fabricants, de la Direction Générale de la Protection de la Santé de Santé Canada, et du Centre de Collaboration pour la Surveillance Internationale des Médicaments de l'Organisation Mondiale de la Santé ont été révisées. RÉSULTATS L'emploi concomitant de sumatriptan et des ISRS ou du lithium a été associé à des symptômes s'apparentant au syndrome sérotoninergique dans 16 et 2 cas, respectivement. Il n'y a pas eu de cas rapporté avec les IMAO. En général, les symptômes rapportés étaient de légers à modérés, et quelques présentations concordaient avec un syndrome sérotoninergique. Les auteurs ont répertorié 148 patients ayant utilisé le sumatriptan et les ISRS qui n'ont eu aucun problème, 31 patients ayant eu des IMAO et quelquesuns ayant eu du lithium. CONCLUSIONS L'évidence clinique supportant une contre-indication absolue de l'emploi des IMAO, des ISRS, ou du lithium concomitamment à celle du sumatriptan n'a pu être démontrée. La plupart des patients tolèrent les associations sumatriptan et ISRS ou lithium sans incident. Comme il y a peu d'informations entourant l'utilisation concomitante du sumatriptan et des IMAO, les auteurs suggèrent qu'il serait prudent d'éviter cette association jusqu'à ce que des données supplémentaires montrent son inocuité.

Objectives Many patients with asthma spend time and resources consuming complementary and alternative medicines (CAMs). This study explores whether CAM utilisation is associated with asthma control and the intake of asthma controller medications. Design Population-based, prospective cross-sectional study. Setting General population residing in two census areas in the province of British Columbia, Canada. Recruitment was based on random-digit dialling of both landlines and cell phones. Participants 486 patients with self-reported physician diagnosis of asthma (mean age 52 years; 67.3% woman). Primary and secondary outcome measures We assessed CAM use over the previous 12 months, level of asthma control as defined by the Global Initiative for Asthma and the self-reported intake of controller medications. Multivariate logistic regression was performed to study the relationship between any usage of CAMs (outcome), asthma control and controller medication usage, adjusted for potential confounders. Results A total of 179 (36.8%) of the sample reported CAM usage in the past 12 months. Breathing exercises (17.7%), herbal medicines (10.1%) and vitamins (9.7%) were the most popular CAMs reported. After adjustment, female sex (OR 1.66; 95% CI 1.09 to 2.52) and uncontrolled asthma (vs controlled asthma, OR 2.25, 95% CI 1.30 to 3.89) were associated with a higher likelihood of using any CAMs in the past 12 months. Controller medication use was not associated with CAM usage in general and in the subgroups defined by asthma control. Conclusions Clinicians and policy makers need to be aware of the high prevalence of CAM use in patients with asthma and its association with lack of asthma control.

OBJECTIVE: The objective of this analysis was to evaluate the impact of social class on correlation between the standardized AQLQ, self-rated asthma severity and control, and patient utility. METHODS: 84 asthmatic subjects completed the AQLQ. Self-rated asthma severity and control was measured on a 5-point Likert scale and utilities were measured using a rating scale. SES was defined based on receipt of social assistance. Correlations between AQLQ scores and each other variable were measured using Spearman's Rank correlation coefficient (rS). Differences in rs between social classes (rsdiff) were analyzed using Fisher's r to z transformation (2-tailed). RESULTS: 38 (45%) patients were receiving social assistance. In the entire sample, there was significant correlation (p < 0.05) between all AQLQ scores (symptoms, activity, emotion, environment, and global), self-rated asthma severity (rS = 0.21–0.38), control (rS = 0.21–0.38), and utilities. Symptom, activity, and global AQLQ scores were correlated strongly with utility (rS = 0.53–0.54; p < 0.0001) and moderately with environment and emotion scores (rS = 0.38;p = 0.002). However, AQLQ scores were consistently more strongly correlated with self-assessed severity and control in lower SES patients. Although rS diff ranged from 0.07 to 0.55 (mean = 0.27), only the most extreme difference was significant (activity score and control − rS diff = 0.55; p = 0.01). Conversely, rS between all AQLQ scores and utility were consistently lower (mean rS diff = 0.18; range 0.9–0.23) in patients on social assistance, although not significantly. CONCLUSIONS: Correlations between AQLQ scores and utility were consistently lower in lower SES subjects, suggesting that AQLQ may be a better measure of overall health in higher SES patients. Conversely, AQLQ scores correlated more strongly with self-rated asthma severity and control in lower SES subjects. Although most differences were not significant despite their magnitude, this is likely due to a recognized lack of power of the Fisher's r to z transformation test.

Summary Background Understanding the views of parents and children is critical to designing effective asthma management programs. It was hypothesized that parents and adolescents would exhibit heterogenous preferences with regard to asthma control. Methods Fifty parents of children with asthma and 51 adolescents with asthma participated in a best–worst scaling study to quantify preferences regarding night-time symptoms, wheezing/chest tightening, changes in asthma medications, emergency visits and physical activity limitations. Results A latent class analysis revealed heterogeneity inherent in the preferences of parents and adolescents. Two classes of parents emerged from the analysis that displayed significantly different preferences. The first displayed strong preferences for averting night-time symptoms, wheezing/chest tightening, physical activity limitations and emergency room visits with odds ratios (OR) of 42 (95% CI 24, 72), 40 (95% CI 23, 68), 26 (95% CI 15, 44) and 21 (95% CI 12, 35), respectively, compared to an OR of 1 for 10 physical activity limitations per month. A second smaller parent class displayed more balanced preferences. Most adolescents displayed similar preferences for averting night-time symptoms, wheezing/chest tightening, physical activity limitations and emergency room visits, with ORs of 28 (95% CI 16, 48), 25 (95% CI 14, 44), 27 (95% CI 15, 46) and 20 (95% CI 11, 34) respectively. Conclusions This study revealed the importance placed on averting night-time symptoms, wheezing and chest tightening, emergency room visits and physical activity limitations by parents and adolescents alike, with greater emphasis on symptom aversion by parents. Preference heterogeneity exists and should be considered in customized asthma management programs.

Objective To estimate and compare the effectiveness of the levonorgestrel and Yuzpe regimens for hormonal emergency contraception in routine clinical practice. Methods A retrospective population-based study included women who accessed emergency contraceptives for immediate use prescribed by community pharmacists in British Columbia, Canada, between December 2000 and December 2002. Linked administrative healthcare data were used to discern the timings of menses, unprotected intercourse, and any pregnancy-related health services. A panel of experts evaluated the compatibility of observed pregnancies with the timing of events. The two regimens were compared with statistical adjustments for potential confounding. Results Among 7493 women in the cohort, 4470 (59.7%) received levonorgestrel and 3023 (40.3%) the Yuzpe regimen. There were 99 (2.2%) compatible pregnancies in the levonorgestrel group and 94 (3.1%) in the Yuzpe group ( P = 0.017). The estimated odds ratio for levonorgestrel compared with the Yuzpe regimen after adjusting for potential confounders was 0.64 (95% confidence interval 0.47–0.87). Against an expected pregnancy rate of approximately 5%, the relative and absolute risk reductions were 56.0% and 2.8%, respectively, for levonorgestrel and 36.7% and 1.8% for the Yuzpe regimen. Conclusion The levonorgestrel regimen is more effective than the Yuzpe regimen in routine use. The data suggest that both regimens are less effective than has been observed in randomized trials.

Background Asthma is associated with enormous healthcare expenditures that include both direct and indirect costs. It is also associated with the loss of future potential earnings related to both morbidity and mortality. The objective of the study is to determine the burden of disease costs associated with asthma. Methods We performed a systematic search of MEDLINE, EMBASE, CINAHL, CDSR, OHE-HEED, and Web of Science Databases between 1966 and 2008. Results Sixty-eight studies met the inclusion criteria. Hospitalization and medications were found to be the most important cost driver of direct costs. Work and school loss accounted for the greatest percentage of indirect costs. The cost of asthma was correlated with comorbidities, age, and disease severity. Conclusion Despite the availability of effective preventive therapy, costs associated with asthma are increasing. Strategies including education of patients and physicians, and regular follow-up are required to reduce the economic burden of asthma.

Background: Asthma is difficult to diagnose in children and at times misdiagnosis of an infection can occur. However, little is known about the magnitude and patterns of antibiotic consumption in children with asthma relative to those without asthma. Methods: Using population-based data, 128,872 children were identified with at least 6 years of follow-up. The adjusted rate-ratio (RR) of antibiotics dispensed to asthmatic as compared to non-asthmatic children was determined. Results: At age six, the RR of antibiotic consumption for asthmatics compared to non-asthmatics varied between, 1.66 to 2.32, depending on the year of asthma diagnosis. Of the 18,864 children with asthma at ages 2-8, 52% (n = 9,841) had antibiotics dispensed in the 6 months prior to their index date of asthma diagnosis. The RR of antibiotic consumption in the 1 month prior to asthma diagnosis compared to 5 months prior was 1.66 (95% CI 1.60-1.71). The RR was lower in males compared to females (1.58 vs 1.77), and lower in those who received antibiotics in the first year of life relative to those that did not (1.60 vs. 1.76). Conclusions: There is higher antibiotic consumption in children with asthma compared to those without asthma. The pattern of antibiotic use suggests that diagnosis guidelines are difficult to follow in young children leading to misdiagnosis and over treatment with antibiotics.

Background: The osmole gap is used routinely as a screening test for the presence of exogenous osmotically active substances, such as the toxic alcohols ethylene glycol and methanol, particularly when the ability to measure serum concentrations of the substances is not available. The objectives of this study were: 1) to measure the diagnostic accuracy of the osmole gap for screening for ethylene glycol and methanol exposure, and 2) to identify whether a recently proposed modification of the ethanol coefficient affects the diagnostic accuracy. Methods: Electronic laboratory records from two tertiary-care hospitals were searched to identify all patients for whom a serum ethylene glycol and methanol measurement was ordered between January 1, 1996 and March 31, 2002. Cases were eligible for analysis if serum sodium, blood urea nitrogen, glucose, ethanol, ethylene glycol, methanol, and osmolality were measured simultaneously. Serum molarity was calculated using the Smithline and Gardner equation and ethanol coefficients of 1 and 1.25 mOsm/mM. The diagnostic accuracy of the osmole gap was evaluated for identifying patients with toxic alcohol levels above the recommended threshold for antidotal therapy and hemodialysis using receiver-operator characteristic curves, likelihood ratios, and positive and negative predictive values. Results: One hundred and thirty-one patients were included in the analysis, 20 of whom had ethylene glycol or methanol serum concentrations above the threshold for antidotal therapy. The use of an ethanol coefficient of 1.25 mOsm/mM yielded higher specificities and positive predictive values, without affecting sensitivity and negative predictive values. Employing an osmole gap threshold of 10 for the identification of patients requiring antidotal therapy resulted in a sensitivity of 0.9 and 0.85, and a specificity of 0.22 and 0. 5, with equations 1 and 2 respectively. The sensitivity increased to 1 for both equations for the identification of patients requiring dialysis. Conclusion: In this sample, an osmole gap threshold of 10 has a sensitivity and negative predictive value of 1 for identifying patients for whom hemodialysis is recommended, independent of the ethanol coefficient applied. In patients potentially requiring antidotal therapy, applying an ethanol coefficient of 1.25 resulted in a higher specificity and positive predictive value without compromising the sensitivity.