# Adjuvant Gabapentinoids Versus Muscle Relaxants to Aid Opioid Discontinuation in Older Adults

## TL;DR

This study found that starting gabapentinoids instead of muscle relaxants in older adults with chronic back pain did not help stop opioid use and was linked to more deaths and hospitalizations.

## Contribution

The study provides new evidence comparing gabapentinoids and muscle relaxants for opioid discontinuation in older adults using large-scale real-world data.

## Key findings

- Gabapentinoid initiation was not associated with higher opioid discontinuation rates compared to muscle relaxants.
- Gabapentinoids were linked to increased mortality and hospitalization rates compared to muscle relaxants.
- The study used real-world data from Medicare and Optum to analyze outcomes in older adults with chronic back pain.

## Abstract

We compared the likelihood to discontinue chronic opioid therapy after initiating gabapentinoids vs. muscle relaxants among community-dwelling older adults with chronic back pain. We conducted a retrospective cohort study of adults ≥65 years of age in U.S. fee-for-service Medicare data (2013-2018) and Optum Clinformatics® Data Mart Database (2004-2023). We included community-dwelling individuals diagnosed with chronic back pain and opioid use lasting >90 consecutive days, who newly initiated gabapentinoids or muscle relaxants. Our primary outcome of opioid discontinuation was defined by an absence of a refill within 60 days of the supply ending. Secondary outcomes included all-cause mortality and all-cause hospitalization. We controlled for 95 covariates using propensity score 1:1 matching. During the 1-year follow-up, we used Cox proportional hazard regression to estimate hazard ratios (HR) and generalized linear models to estimate risk difference (RD). We pooled database-specific estimates with inverse-variance weighting. We matched 17,063 muscle relaxant and gabapentinoid initiators from Medicare (Mean age [SD]=74 [6] years, female=67%, White=74%) and 138,141 from Optum (Mean age [SD]=74 [7] years, female=71%, White=88%). Compared to muscle relaxant initiators, gabapentinoid initiation was not associated with the rate of discontinuing opioids (HR [95% CI], 0.97 [0.84, 1.11]; RD [95% CI] per 1,000 PYs, -55.4 [-191.3, 80.6]). However, gabapentinoid initiation was associated higher rates of death (HR [95% CI], 1.08 [1.01, 1.16]; RD per 1,000 PYs, 1.6 [0.4, 2.9] and hospitalization (HR, 1.09 [1.06, 1.11]; RD per 1,000 PYs, 33.4 [14.5, 52.4]). Compared to muscle relaxants, initiating gabapentinoids was associated with a higher likelihood of adverse events.