Therapeutic and Subtherapeutic Dosing of Pregabalin: Medication Adherence, Healthcare Resource Utilization, and Costs

Objectives: To compare adherence and direct medical costs with therapeutic and subtherapeutic doses of pregabalin for the treatment of fi bromyalgia (FM), post-herpetic neuralgia (PHN), and painful diabetic peripheral neuropathy (pDPN). Study Design: Retrospective database analysis. Methods: Adult patients (> 18 years old) newly given pregabalin for FM, PHN, or pDPN between October 1, 2007, and October 1, 2008, were identifi ed using the MarketScan Database. Therapeutic and subtherapeutic doses were based on the FDA-approved label. Outcomes, including proportion of days covered [PDC], persistence, and direct medical costs, were compared between dose categories using.2 tests, t tests, and multivariable analyses adjusting for clinical and demographic variables. Results: Of 21,768 patients (70% FM, 7% PHN, 23% pDPN), 13.1% (n = 2873) were given therapeutic doses of pregabalin. Within each of the indications, the average daily subtherapeutic dose was signifi cantly lower than the therapeutic dose (P <. 0001). Relative to patients with subtherapeutic doses, patients with therapeutic doses had higher PDC, percent with PDC > 80%, greater persistence, and were more likely to be on therapy after 1 year. Mean total direct costs (per patient per 6 months) were similar between therapeutic and subtherapeutic doses within each indication despite signifi cantly higher therapeutic pharmacy costs (FM $ 3560 vs $ 3041, P <. 0001; PHN $ 2352 vs $ 2333, P =.08; pDPN $ 4020 vs $ 3524, P <. 0001). Conclusions: Among the indications, patients with pregabalin were frequently given a subtherapeutic dose, which was associated with poorer adherence. Additionally, pharmacy costs were signifi cantly higher with therapeutic relative to subtherapeutic dosing, but nevertheless resulted in comparable total direct medical costs between dose groups, suggesting that prescribing pregabalin at its recommended therapeutic dose may increase adherence without increasing cost relative to subtherapeutic dosing.