Impact of a step-therapy protocol for pregabalin on healthcare utilization and expenditures in a commercial population

Abstract

Objective:To compare changes in healthcare resource utilization and costs among members with painful diabetic peripheral neuropathy (pDPN), postherpetic neuralgia (PHN), or fibromyalgia (FM) in a commercial health plan implementing pregabalin step-therapy with members in unrestricted plans.Methods:Retrospective study of outcomes associated with implementation of a pregabalin step-therapy protocol using claims data from Humana (‘restricted’ cohort) and Thomson Reuters MarketScan (‘unrestricted’ cohort). Members aged 18–65 years receiving treatment for pDPN, PHN, or FM during 2008 or 2009 were identified; cohorts were matched on diagnosis and geographic region. Baseline to follow-up changes in healthcare resource utilization and costs were determined using difference-in-differences (DID) analysis. Statistical models adjusting for covariates explored relationships between restricted access and outcomes.Results:A total of 3876 restricted cohort members were identified and matched to 3876 unrestricted cohort members. FM was the predominant diagnosis (84.7%). The unrestricted cohort was older (mean = 49.0 (SD = 10.4) years vs 47.6 (SD = 10.5) years; p < 0.001), and had greater comorbidity (RxRisk-V score = 5.4 (SD = 3.2) vs 4.4 (SD = 2.9), p < 0.001) than the restricted cohort. Compared with the unrestricted cohort, the restricted cohort demonstrated a greater year-over-year decrease in pregabalin utilization (−2.6%, p = 0.008), and greater increases in physical therapy and disease-related outpatient utilization (3.7%, p = 0.010 and 3.6%, p = 0.022, respectively). There were no statistically significant net differences in all-cause or disease-related total healthcare, medical, or pharmacy costs between cohorts. After adjusting for baseline compositional differences between cohorts, restricted plan membership was associated with a net increase in all-cause medical ($1222; p = 0.016) and disease-related healthcare costs ($859; p = 0.002). Limitations include use of a combined analysis for pDPN, PHN, and FM, especially since the observed results were likely driven by FM; an inability to link the prescribing of a medication with the condition of interest, which is common to claims analyses; and lack of pain severity information.Conclusions:Implementation of a pregabalin step-therapy protocol resulted in lower pregabalin utilization, but this restriction was not associated with reductions in total healthcare costs, medical costs, or pharmacy costs.