Comparative Health-Care Cost Advantage of Ipratropium over Tiotropium in COPD Patients

Objective: To compare the total direct health-care costs of patients treated with tiotropium and ipratropium. Methods: We conducted a cohort study of health-care costs in British Columbia, Canada, by comparing new patients on tiotropium with new patients on ipratropium. Direct health-care costs for study patients were measured in the first 2 years after initiating inhaled anticholinergic treatment. Differences in direct health-care costs between tiotropium and ipratropium patients were estimated by using quantile regression. We analyzed cost differences in the 10th percentile, median, and 90th percentile of patients by cost. High-dimensional propensity score analysis was used as a method of adjustment for potential confounding factors. Results: The study population had 3,140 tiotropium patients and 26,182 ipratropium patients. Higher health system costs in patients who started on tiotropium instead of ipratropium were observed in patients in the median and 10th percentile. The magnitude of these increases was comparable to the price difference between the two drugs. Health system costs in the 90th percentile were not significantly different between tiotropium and ipratropium patients. Conclusions: The results of this study did not support the preferential use of tiotropium over ipratropium as a basis for savings in direct health-care costs

Rosiglitazone and Myocardial Infarction in Patients Previously Prescribed Metformin

Objective: Rosiglitazone was found associated with approximately a 43% increase in risk of acute myocardial infarction (AMI) in a two meta-analyses of clinical trials. Our objective is to estimate the magnitude of the association in real-world patients previously treated with metformin. Research Design and Methods: We conducted a nested case control study in British Columbia using health care databases on 4.3 million people. Our cohort consisted of 158,578 patients with Type 2 diabetes who used metformin as first-line drug treatment. We matched 2,244 cases of myocardial infarction (AMI) with up to 4 controls. Conditional logistic regression models were used to estimate matched odds ratios for AMI associated with treatment with rosiglitazone, pioglitazone and sulfonylureas. Results: In our cohort of prior metformin users, adding rosiglitazone for up to 6 months was not associated with an increased risk of AMI compared to adding a sulfonylurea (odds ratio [OR] 1.38; 95% confidence interval [CI], 0.91–2.10), or compared to adding pioglitazone (OR for rosi versus pio 1.41; 95% CI, 0.74–2.66). There were also no significant differences between rosiglitazone, pioglitazone and sulfonylureas for longer durations of treatment. Though not significantly different from sulfonylureas, there was a transient increase in AMI risk associated with the first 6 months of treatment with a glitazone compared to not using the treatment (OR 1.53; 95% CI, 1.13–2.07) Conclusions: In our British Columbia cohort of patients who received metformin as first-line pharmacotherapy for Type 2 diabetes mellitus, further treatment with rosiglitazone did not increase the risk of AMI compared to patients who were treated with pioglitazone or a sulfonylurea. Though not statistically significantly different compared from each other, an increased risk of AMI observed after starting rosiglitazone or sulfonylureas is a matter of concern that requires more research

Pioglitazone use in Australia and the United Kingdom following drug safety advisories on bladder cancer risk: An interrupted time series study

Purpose: National regulators in Australia and the United Kingdom issued safety advisories on the association between pioglitazone use and bladder cancer in July 2011. The Australian advisory noted that males were at higher risk of bladder cancer than females, while the UK advisory highlighted a new recommendation, suggest careful consideration in the elderly due to increasing risk with age. This study examined whether these differences in the advisories had different age- and sex-based impacts in each country. Methods: Interrupted time series analysis was used to compare pioglitazone use (prescriptions/100000 population) in Australia and the United Kingdom for the 24 months before and 11 months after the July 2011 safety advisories (study period July 2009–June 2012). Separate models were used to compare use by sex and age group (≥65 years vs. <65 years) in each country. Results: Pioglitazone use fell in Australia (17%) and the United Kingdom (24%) following the safety advisories. Use of pioglitazone fell more for males (18%) than females (16%) in Australia, and more for females (25%) than males (23%) in the United Kingdom; however, neither difference was statistically significant (Australia p = 0.445, United Kingdom p = 0.462). Pioglitazone use fell to a similar extent among older people than younger people in the United Kingdom (23% vs. 26%, p = 0.354), and did not differ between age groups in Australia (both 18%, p = 0.772). Conclusions: The results indicate that differences in the Australian and UK safety advisories resulted in substantial reductions in pioglitazone use at the population level in both countries, however, differences by sub-groups were not observed

Influence of drug safety advisories on drug utilisation: an international interrupted time series and meta-analysis

OBJECTIVE: To evaluate the association between regulatory drug safety advisories and changes in drug utilisation. DESIGN: We conducted controlled, interrupted times series analyses with administrative prescription claims data to estimate changes in drug utilisation following advisories. We used random-effects meta-analysis with inverse-variance weighting to estimate the average postadvisory change in drug utilisation across advisories. STUDY POPULATION: We included advisories issued in Canada, Denmark, the UK and the USA during 2009-2015, mainly concerning drugs in common use in primary care. We excluded advisories related to over-the-counter drugs, drug-drug interactions, vaccines, drugs used primarily in hospital and advisories with co-interventions within ±6 months. MAIN OUTCOME MEASURES: Change in drug utilisation, defined as actual versus predicted percentage change in the number of prescriptions (for advisories without dose-related advice), or in the number of defined daily doses (for dose-related advisories), per 100 000 population. RESULTS: Among advisories without dose-related advice (n=20), the average change in drug utilisation was -5.83% (95% CI -10.93 to -0.73; p=0.03). Advisories with dose-related advice (n=4) were not associated with a statistically significant change in drug utilisation (-1.93%; 95% CI -17.10 to 13.23; p=0.80). In a post hoc subgroup analysis of advisories without dose-related advice, we observed no statistically significant difference between the change in drug utilisation following advisories with explicit prescribing advice, such as a recommendation to consider the risk of a drug when prescribing, and the change in drug utilisation following advisories without such advice. CONCLUSIONS: Among safety advisories issued on a wide range of drugs during 2009-2015 in 4 countries (Canada, Denmark, the UK and the USA), the association of advisories with changes in drug utilisation was variable, and the average association was modest

Hydroxyzine Initiation Following Drug Safety Advisories on Cardiac Arrhythmias in the UK and Canada: A Longitudinal Cohort Study

INTRODUCTION: Regulatory advisories on hydroxyzine and risk of QT prolongation and Torsade de pointes (TdP) were issued in the UK in April 2015 and Canada in June 2016. We hypothesized patients with risk factors for QT prolongation and TdP, compared with those without risk factors, would be less likely to initiate hydroxyzine in the UK and in British Columbia (BC), Canada, following advisories. METHODS: We conducted a longitudinal study with repeated measures, and evaluated hydroxyzine initiation in a UK cohort and a concurrent BC control cohort (April 2013-March 2016) as well as in a BC advisory cohort (June 2014-May 2017). RESULTS: This study included 247,665 patients in the UK cohort, 297,147 patients in the BC control cohort, and 303,653 patients in the BC advisory cohort. Over a 12-month post-advisory period, hydroxyzine initiation decreased by 21% in the UK (rate ratio 0.79, 95% confidence interval 0.66-0.96) relative to the expected level of initiation based on the pre-advisory trend. Hydroxyzine initiation did not change in the BC control cohort or following the Canadian advisory in the BC advisory cohort. The decrease in hydroxyzine initiation in the UK in the 12 months after the advisories was not significantly different for patients with risk factors compared with those without risk factors. CONCLUSION: Hydroxyzine initiation decreased in the UK, but not in BC, in the 12 months following safety advisories. The decrease in hydroxyzine initiation in the UK was not significantly different for patients with versus without risk factors for QT prolongation and TdP

Determining the primary endpoints for diagnostic test accuracy reviews of substance use disorders

Diagnostic test accuracy reviews increasingly are being used in substance use research, yet the majority of the studies considered in these reviews do not account appropriately for the primary endpoints of interest. Recently, the DSM-5 criteria have been largely criticized as poorly able to properly distinguish those with problematic use from those with substance use disorders.Medicine, Faculty ofOther UBCAnesthesiology, Pharmacology and Therapeutics, Department ofMedicine, Department ofReviewedFacultyPostdoctora

On the Evaluation of Drug Benefits Policy Changes with Longitudinal Claims Data: Concepts of Income-Based Deductibles and Issues Related to Causal Inference

Cost containment in pharmaceutical benefits plans is often controversial because of its potential for unintended effects on health and overall expenditures. Thorough evaluations are needed to support benefits plans in developing evidence-based policies. Evaluations of income-based deductibles for prescription drugs using non-experimental data are challenging because the time until patients' expenses exceed their annual deductible varies with the number of drugs used, which depends on their health status and income. We sought to clarify conceptual and methodological issues in longitudinal designs to evaluate income-based deductibles for prescription drugs, and provide a framework for the evaluation of such policies using longitudinal claims data. One of the main challenges is the violation of the Exclusion Restriction Assumption, which is a standard assumption when using instrumental variables such as the start date of a new policy. This assumption requires the instrumental variable to be independent of subject characteristics, such as income and health status. The validity of an evaluation therefore depends on the ability to measure and adjust for these characteristics. Given the lack of such data, randomization of the policy may be a more valid study design.Cost containment, Pharmacoeconomics, Reimbursement