Impact of fixed-dose and multi-pill combination dyslipidemia therapies on medication adherence and the economic burden of sub-optimal adherence.

OBJECTIVE: To compare medication adherence between patients initiating fixed-dose combination versus multi-pill combination dyslipidemia therapies and assess the association between optimal adherence (MPR > or = 80%) and cardiovascular disease (CVD)-associated total healthcare resource utilization (THR) and costs (THC). RESEARCH DESIGN AND METHODS: The HealthCore Integrated Research Database was used to identify patients > or =18 years newly initiating fixed-dose combination [niacin extended-release (NER) and lovastatin (NERL)] or multi-pill combination therapies [NER and simvastatin (NER/S) or lovastatin (NER/L)] between 1/1/2000 and 6/30/2006 (index date), with minimum 18 months of follow-up. Adherence was measured using medication possession ratio (MPR). Three multivariate models were developed controlling for demographic and clinical characteristics. A logistic model evaluated the association between study cohorts and optimal adherence, while negative binomial and gamma models estimated the association between optimal adherence and CVD-associated THR and THC, respectively. RESULTS: In all, 6638 NERL, 1687 NER/S, and 663 NER/L patients were identified. Fixed-dose combination patients were younger [mean (SD) ages of 51.9 (10.5) vs. 56.0 (9.4) [NER/S] and 56.1 (10.6) [NER/L]; p < 0.01], had lower comorbidity (Deyo-Charlson Index 0.50 +/- 0.9 vs. 0.7 +/- 1.1 and 0.6 +/- 1.1, p < 0.01 and p < 0.05) and comprised fewer males (73.1 vs. 83.0% and 77.7%; p < 0.01 and p = 0.1). Fixed-dose combination patients had higher average 1-year MPR versus NER/S and NER/L patients (0.54 +/- 0.35 vs. 0.50 +/- 0.35 and 0.47 +/- 0.34, p < 0.01). NER/S and NER/L patients were 31.3% (95% CI: 22.9-39.5%) and 39.1% (95% CI: 26.7-49.4%) less likely to be optimally adherent than fixed-dose combination patients (p < 0.01). Additionally, optimally adherent patients had 8% and 40% decreases in annual CVD-attributable THR [0.920 (95% CI: 0.857-0.989); p = 0.023] and THC [0.601 (95% CI: 0.427-0.845); p = 0.003] versus sub-optimally adherent patients. Key limitations of the study include the limited ability of MPR to analyze the continuity of medication usage, inability to capture data on other key variables including race, income, and clinical characteristics such as smoking history, absence of laboratory values on all study patients, inability to capture over-the-counter fills of niacin, and inability to show causality of results obtained. CONCLUSIONS: Adherence was significantly higher among patients initiating fixed-dose combination versus multi-pill combination dyslipidemia therapies in this managed-care population. Additionally, patients with optimal adherence had a significantly lower CVD-associated THR and THC versus patients with sub-optimal adherence.

Resource utilization impact of topiramate for migraine prevention in the managed-care setting.

OBJECTIVE: To determine the pattern of headache-related resource utilization and costs before and after initiation of preventive migraine treatment with topiramate in a sample of a large managed-care population. METHODS: This study was a retrospective, longitudinal, cohort study analysis of medical and pharmacy claims using The HealthCore Integrated Research Network Database. Patients were required to have had at least one pharmacy claim for topiramate between 7/1/00 and 11/30/04, and at least 12 dosage units dispensed of any combination of acute migraine treatments (triptan, ergotamine, or ergotamine combination) during the 6-month period preceding the first pharmacy claim for topiramate (the index date). Headache-related inpatient and outpatient resource utilizations were compared pre-index vs. post-index period 1 (months 1-6) and pre-index vs. post-index period 2 (months 7-12). Statistical analyses included McNemar tests for categorical variables and paired t-tests for continuous variables. RESULTS: A total of 3246 patients met the inclusion criteria. The mean (+/- SD) age was 44 +/- 10 years and 88% were female. From pre- to post-index period 2, outpatient visits significantly decreased by 30% (p < 0.0001), diagnostic procedures decreased by 74% (p = 0.0013), emergency room (ER) visits decreased by 27% (p < 0.0001), and abortive prescriptions decreased by 25% (p < 0.0001). No significant differences were found in mean number of hospitalization days. Total headache-related inpatient costs and outpatient costs decreased (p < 0.01) during post-index period 2 (43 and 46%, respectively). Headache-related pharmacy costs increased from pre- to post-index period 2. CONCLUSION: Topiramate treatment for migraine prevention was associated with significantly lower healthcare resource use (ER visits, diagnostics, acute treatment) in the first 6 months of treatment, with continuing decreases, including physician office visits, during the second 6 months of treatment. LIMITATIONS: Since this study is a claims-based analysis there is the potential introduction of non-claims identifiable factors that might influence resource use such as lifestyle modifications and over-the-counter medications. In addition, adherence to topiramate treatment was not accounted for in this study. Nonetheless, this study provides important insights into the benefit of preventive migraine treatment in actual clinical practice.

Persistence with migraine prophylactic treatment and acute migraine medication utilization in the managed care setting.

OBJECTIVE: The aim of this study was to describe persistence with migraine prophylactic treatment and acute migraine medication utilization in patients prescribed migraine prophylaxis. METHODS: For this retrospective cohort study, the Health Core Integrated Research Database provided pharmacy/medical claims data from 5 commercial health insurance plans (ie, excluding Medicare and Medicaid) on adult patients with migraine. Eligible patients had >or=1 pharmacy claim for a migraine prophylactic medication between July 1, 2000, and May 31, 2005, and >or=12 U of any combination of acute treatment (serotonin receptor agonist [triptan], ergotamine, or ergotamine combination) dispensed during the 180-day period preceding a first pharmacy claim for a prophylactic medication (index date). The prophylactic medication identified at index date was used for categorizing patients into 1 of 4 cohorts: amitriptyline, propranolol/timolol, divalproex sodium, or topiramate (reference). Kaplan-Meier curves were used for evaluating unadjusted risk for discontinuation over time, and a multivariate Cox proportional hazards model was developed to analyze factors associated with discontinuation of prophylactic medication. RESULTS: A total of 12,783 patients met the inclusion criteria and were included in the analysis (amitriptyline, 3749; propranolol/timolol, 2718; divalproex sodium, 1644; and topiramate, 4672). The mean (SD) ages were not significantly different across cohorts (43.9 [11.3], 42.0 [11.1], 43.1 [11.3], and 43.9 [10.6] years, respectively). The mean duration of treatment was significantly longer (131 [184] days) with topiramate compared with amitriptyline (94 [152] days), propranolol/ timolol (119 [180] days), and divalproex sodium (109 [158] days) (P < 0.001, P = 0.005, and P<0.001,respectively). The risks for discontinuing prophylactic treatment were 23%, 6%, and 11% higher with amitriptyline, propranolol/timolol, and divalproex sodium, respectively, compared with topiramate (P<0.001, P = 0.024, and P <0.001). Patients prescribed topiramate had a higher mean consumption rate of triptans preindex; postindex, decreases in triptan use were observed in all cohorts, although the magnitude of the decrease was greatest in patients prescribed topiramate compared with the other cohorts. CONCLUSIONS: In this study, prescription of topiramate was associated with greater persistence with prophylactic treatment than the other prophylactic drugs. Furthermore, greater reductions in acute treatment utilization, particularly triptans, were observed among patients prescribed topiramate compared with the other prophylactic cohorts.