MA3 Comparative Outcomes of Fibromyalgia Patients Who Initiated Duloxetine or Pregabalin: Medication Adherence and Direct Medical Costs

Abstract

COMPARATIVE OUTCOMES OF FIBROMYALGIA PATIENTS WHO INITIATED DULOXETINE OR PREGABALIN: MEDICATION ADHERENCE AND DIRECT MEDICAL COSTS Sun P1, Peng X2, Sun S3, Novick D4, Faries D2, Andrews J2, Wu A5, Wohlreich M2 1Kailo Research Group, Fishers, IN, USA, 2Eli Lilly and Company, Inc., Indianapolis, IN, USA, 3Kailo Research Group, Fremont, CA, USA, 4Eli Lilly and Company, Inc., Windlesham, Surrey, UK, 5Kailo Research Group, Los Angeles, CA, USA OBJECTIVES: To compare medication adherence and direct medical costs between duloxetine and pregabalin among fibromyalgia patients. METHODS: A retrospective cohort study design was used along with a large US national commercial claims database (2006 2009). Fibromyalgia patients who initiated duloxetine or pregabalin in 2008 at age between 18 and 64, and with continuous health insurance 1 year before and 1 year after initiation were assigned to a duloxetine initiator cohort or a pregabalin initiator cohort based on their initiated agent. Medication adherence of duloxetine or pregabalin, measured by total supply days, medication possession ratio (MPR) and proportion of patients with MPR 0.8, and direct medical costs, measured by annual costs per patient, were assessed and compared between the cohorts in the year following the initiation. Bootstrapping and propensity score stratification methods were used to adjust for distribution bias, as well as cross-cohort differences in demographics, clinical and economic characteristics, and medication history prior to the initiation. RESULTS: Both the duloxetine (n 3,033) and pregabalin (n 4,838) cohorts had a mean initiation age around 49 years, 89% were female. In the post-initiation year, compared to the pregabalin cohort, the duloxetine cohort had higher totally annual supply days (273.5 vs. 176.6, p 0.05), higher MPR (0.7 vs. 0.5, p 0.05) and more patients with MPR 0.8 (45.1% vs. 29.4%, p 0.05). Further, relative to pregabalin initiators, duloxetine initiators had lower inpatient costs ($2,994.9 vs. $4,949.6, p 0.05), low outpatient costs ($8,259.6 vs. $10,312.2, p 0.05), similar medication costs ($5,214.6 vs. $5,290.8, p 0.05), and lower total costs ($16,469.1 vs. $20,552.6, p 0.05) in the post-initiation year. CONCLUSIONS: In a real-world setting, fibromyalgia patients who initiated duloxetine in 2008 were associated with higher adherence and lower inpatient, outpatient and total medical costs than those who initiated pregabalin.