(B-131) Trends, Patterns, and Characteristics of Gabapentin Use among Medicare Beneficiaries (2012-2021)

Background: Gabapentin is increasingly prescribed to older adults, yet little is known about what kind of patients receive these prescriptions or for how long.

Objectives: To examine 1) gabapentin prevalence and initiation among Medicare fee-for-service beneficiaries from 2012 to 2021 and 2) patterns and characteristics of their gabapentin use.

Methods: We conducted a retrospective cohort study using a random sample of age-eligible fee-for-service Medicare beneficiaries (2012-2021) enrolled in Parts A, B, and D. The annual prevalence was calculated as the number of beneficiaries with at least one gabapentin prescription divided by the total eligible beneficiaries per year (2012-2021). Gabapentin initiators were identified from Part D pharmacy claims as those with a prescription fill following ≥180 days of continuous enrollment (washout period) prior to initiation (index date). We analyzed demographics, recent medical history (past three months), chronic conditions prior to gabapentin initiation, medication history during washout period, and patterns of gabapentin use. Subgroup analyses compared baseline characteristics across groups defined by days of continuous gabapentin use (≤90 days, 91–180 days, and >180 days).

Results: The prevalence of gabapentin prescriptions increased over time, from 6.3% (2012) to 10.2% (2021). Among 247,223 gabapentin initiators (mean age: 76.1 years), 61.5% were female and 89.2% were white. Chronic pain was the most common condition documented among gabapentin initiators, while epilepsy and postherpetic neuralgia, the approved indications, were reported among < 0.5% of initiators. Among initiators, 38.8% had prior opioid use, and 13.2% were co-prescribed gabapentin and opioids at index. About 30% had a history of antidepressant use, predominantly selective serotonin reuptake inhibitors (17.2%). Continuous gabapentin use for 90, 180, and 365 days was observed in 46%, 25%, and 15% of gabapentin initiators, respectively. Subgroup analysis showed minimal demographic or prescription pattern differences across continuous use groups, though those with >180 days of continuous use had more frequent claims for neuropathic pain and chronic condition diagnoses, fewer opioid co-prescriptions at index, and lower hospitalization rate.

Conclusions: Gabapentin use among older adults is increasing, primarily for off-label conditions. Gabapentin initiators had a high burden of chronic pain and comorbidities, with frequent co-prescription of gabapentin and opioids. Future research is needed to investigate factors associated with continuous gabapentin use and its appropriateness in this population.