Abstract
BACKGROUND: Gabapentin is increasingly prescribed to older adults, yet prescribing patterns and characteristics of gabapentin initiators remain unclear. METHODS: We conducted a retrospective cohort study of gabapentin initiators using a random sample of age-eligible fee-for-service Medicare beneficiaries (2012-2021) enrolled in Parts A, B, and D. Gabapentin initiators were identified from pharmacy claims. We required 180 days of continuous enrollment (washout period) prior to initiation (index date) for inclusion. We analyzed demographics, healthcare utilization within 3 months of initiation, chronic conditions, medication history during washout period, and patterns of gabapentin use. Subgroup analyses compared initiators by duration of continuous gabapentin use (≤ 90 days, 91-180 days, and > 180 days). RESULTS: The prevalence of gabapentin prescriptions increased over time, from 6.7% (2013) to 10.2% (2021). Among 247,612 gabapentin initiators (mean age 76.1 years, 61.5% female, 89.2% white), chronic pain (32.6%) was the most commonly documented condition, while epilepsy and postherpetic neuralgia, the approved indications for gabapentin, were documented in fewer than 0.5% of initiators. Among initiators, 38.9% had prior opioid use, and 13.2% were co-prescribed gabapentin and opioids at initiation. About 30% had a history of antidepressant use, predominantly selective serotonin reuptake inhibitors (17.2%). Subgroup analyses showed similar demographics and prescription patterns across subgroups. However, gabapentin initiators with > 180 days continuous use had more neuropathic pain and chronic condition diagnoses documented, fewer opioid co-prescriptions at index, and lower hospitalization rates. CONCLUSIONS: Gabapentin was frequently prescribed, apparently off-label, in older adults with a high burden of chronic pain and comorbidities; initiators often had co-prescriptions of gabapentin with opioids. Future research is needed to investigate factors associated with extended gabapentin use (> 180 days) and its appropriateness in this population.