The long-term cost-effectiveness of varenicline (12-week standard course and 12 + 12-week extended course) vs. other smoking cessation strategies in Canada.

BACKGROUND: Smoking is the leading risk factor for preventable morbidity and mortality as a result of heart and lung diseases and various forms of cancer. Reimbursement coverage for smoking cessation therapies remains limited in Canada and the United States despite the health and economic benefits of smoking cessation. OBJECTIVES: This study aimed to evaluate the long-term cost-effectiveness of varenicline compared with other smoking cessation interventions in Canada using the Benefits of Smoking Cessation on Outcomes (BENESCO) model. METHODS: Efficacy rates of the standard course (12 weeks) varenicline, extended course (12 + 12 weeks) varenicline, bupropion, nicotine replacement therapy and unaided intervention were derived based on a published mixed treatment comparison methodology and analysed within a Markov cohort model to estimate their cost-effectiveness over the lifetime cycle. Study cohort, smoking rates and prevalence, incidence and mortality of smoking-related diseases were calibrated to represent the Canadian population. RESULTS: Over the subjects' lifetime, both the standard and the extended course of varenicline are shown to dominate (e.g. less costly and more effective) all other alternative smoking cessation interventions considered. Compared with the standard varenicline treatment course, the extended course is highly cost-effective with an incremental cost-effectiveness ratio (ICER) less than $4000 per quality-adjusted life year. Including indirect cost and benefits of smoking cessation interventions further strengthens the result with the extended course of varenicline dominating all other alternatives considered. LIMITATIONS: Evidence from complex smoking cessation models requiring numerous inputs and assumptions should be assessed in conjunction with evidence from other methodologies. CONCLUSIONS: The standard and extended courses of varenicline are decidedly cost-effective treatment regimes compared with alternative smoking cessation interventions and can provide significant cost savings to the healthcare system.

Generic antiepileptic drugs and associated medical resource utilization in the United States.

OBJECTIVE: To evaluate whether generic substitution was associated with any difference in medical resource utilization for 5 widely used antiepileptic drugs (AEDs) in the United States. METHODS: Health insurance claims from PharMetrics Database, representing over 90 health plans between January 2000 and October 2007, were analyzed. Adult patients with epilepsy, continuously treated with carbamazepine, gabapentin, phenytoin, primidone, or zonisamide, were selected. An open-cohort design was used to classify patients into mutually exclusive periods of brand vs generic use of AEDs. Pharmacy and medical utilization were compared between the 2 periods with multivariate regression analyses. Results were stratified into epilepsy-related medical services, and stable (< or = 2 outpatient visits per year and no emergency room visit) vs unstable epilepsy. Time-to-event analyses were also performed for all services and epilepsy-related endpoints. RESULTS: A total of 18,125 patients were observed in the stable group and 15,500 patients in the unstable group. After adjustment of covariates, periods of generic AED treatment were associated with increased use of all prescription drugs (incidence rate ratio [IRR] [95% confidence interval (CI)] = 1.13 [1.13-1.14]) and higher epilepsy-related medical utilization rates (hospitalizations: IRR [95% CI] = 1.24 [1.19-1.30]; outpatient visits: IRR [95% CI] = 1.14 [1.13-1.16]; lengths of hospital stays: IRR [95% CI] = 1.29 [1.27-1.32]). Generic-use periods were associated with increased utilization rates in stable and unstable patients and with 20% increased risk of injury, compared to periods with brand use of AEDs. CONCLUSIONS: Generic antiepileptic drug use was associated with significantly greater medical utilization and risk of epilepsy-related medical events, compared to brand use. This relationship was observed even in patients characterized as stable. AED = antiepileptic drug; CI = confidence interval; ER = emergency room; HR = hazard ratio; ICD = International Classification of Diseases; IRR = incidence rate ratio.

The risks and costs of multiple-generic substitution of topiramate.

OBJECTIVE: To investigate clinical and economic consequences following generic substitution of one vs multiple generics of topiramate (Topamax; Ortho-McNeil Neurologics, Titusville, NJ). METHODS: Medical and pharmacy claims data of Régie de l'Assurance-Maladie du Québec from January 2006 to October 2007 were used. Patients with epilepsy treated with topiramate were selected. An open-cohort design was used to classify the observation period into periods of brand, single-generic, and multiple-generic use. One-year generic-switch and switchback-to-brand rates were estimated using Kaplan-Meier methodology. Medical resource utilization and costs were compared among the three periods using multivariate regression analysis. RESULTS: In total, 948 patients were observed during 1,105 person-years of brand use, 233 person-years of single-generic use, and 92 person-years of multiple-generic use. A total of 23% of generic users received at least two different generic versions. Compared to brand use, multiple-generic use was associated with higher utilization of other prescription drugs (incidence rate ratio [IRR] = 1.27, 95% confidence interval [CI] = 1.24-1.31), higher hospitalization rates (0.48 vs 0.83 visit/person-year, IRR = 1.65, 95% CI = 1.28-2.13), and longer hospital stays (2.6 vs 3.9 days/person-year, IRR = 1.43, 95% CI = 1.27-1.60), but the effect was less pronounced in single-generic use (hospitalization: IRR = 1.08, 95% CI = 0.88-1.34, length of stay: IRR = 1.12, 95% CI = 1.03-1.23). The risk of head injury or fracture was nearly three times higher (hazard ratio = 2.84, 95% CI = 1.24-6.48) following a generic-to-generic switch compared to brand use. The total annualized health care cost per patient was higher in the multiple-generic than brand periods by C$1,716 (cost ratio = 1.21, p = 0.0420). CONCLUSION: Multiple-generic substitution of topiramate was significantly associated with negative outcomes, such as hospitalizations and injuries, and increased health care costs.

Clinical consequences of generic substitution of lamotrigine for patients with epilepsy.

OBJECTIVES: To measure the proportions of patients switching from generic to branded drugs among users of antiepileptic drugs (AED) compared to other therapeutic areas and to investigate medical services utilization associated with generic switching of lamotrigine. METHODS: Medical and pharmacy claims data from Régie de l'Assurance Maladie du Québec database from April 1998 to July 2006 were used. Patients with an epilepsy diagnosis (International Classification of Diseases-9 345) and treated with lamotrigine for >60 of the 90 days before the entry date of generic lamotrigine in Quebec (February 1, 2003) were selected. The proportion of patients switching back to brand were calculated for lamotrigine, for other AEDs (clobazam, carbamazepine CR, gabapentin) and for non-AED chronic medications (carvedilol, fosinopril, simvastatin). Medical resource utilization was compared between periods of branded vs generic use of lamotrigine. RESULTS: Of 671 patients treated with branded lamotrigine, 187 patients (27.9%) switched to a generic, and 51 of these patients (27.5%) switched back to the branded medication. Rates of switchback were from 20.8% to 44.1% for various AEDs and from 7.7% to 9.1% for non-AEDs. Relative to the branded lamotrigine use period, generic lamotrigine use period was associated with a 5.1% increase in mean daily dose of lamotrigine (239.1 vs 251.4 mg; p = 0.0149), a higher number of dispensations for other AEDs (20.4 vs 23.9 dispensations per person-year; p < 0.001) as well as non-AED drugs (26.4 vs 32.8 dispensations per person-year; p < 0.0001), a higher utilization rate of medical services (8.7 vs 9.8 visits per person-year; p < 0.0001), and a longer hospital length of stay (3.29 days vs 4.86 days per person-year; p < 0.0001). CONCLUSION: A higher propensity to switch back to branded medications was observed among antiepileptic drug users compared to users of antihypertensives and antihyperlipidemics, similar to findings from Andermann et al. Switch to generic lamotrigine was significantly associated with increased physician visits and hospitalizations.