Patients with inflammatory arthritis who used gabapentinoids showed a 36% higher risk of fractures compared with past users, according to a study.

The nested case-control study, published in BMC Medicine and conducted through the Clinical Practice Research Datalink Aurum, examined 2,485 cases and 12,244 controls with inflammatory arthritis between 2004 and 2021. Investigators analyzed data from patients with rheumatoid arthritis, psoriatic arthritis, and axial spondyloarthritis who had received gabapentinoid prescriptions.

The analysis found that current gabapentinoid users had an adjusted odds ratio (OR) of 1.36 (95% confidence interval [CI] = 1.22–1.51) for fractures compared to remote users. Both gabapentin (OR = 1.38, 95% CI = 1.19–1.60) and pregabalin (OR = 1.40, 95% CI = 1.18–1.66) showed similar associations. Recent users, who had taken gabapentinoids 1 to 60 days prior to the index date, demonstrated an adjusted OR of 1.70 (95% CI = 1.38–2.09).

The data indicated higher risk during the initial treatment period, with significant associations in the first five deciles of use duration. For fragility fractures, current gabapentin use showed an association (OR = 1.48, 95% CI = 1.20–1.82), whereas pregabalin did not show a statistically significant relationship.

The study population reflected broader prescribing patterns, as approximately 10% of patients with inflammatory arthritis in England received gabapentinoid prescriptions in 2020.

The investigators controlled for various factors by comparing current users to past users rather than nonusers, and by adjusting for demographics, comorbidities, and concurrent medications. Study limitations included potential unmeasured confounding factors and the inability to determine absolute fracture risk rates as a result of the case-control study design.

This study represented the first examination of gabapentinoid-associated fracture risk specifically in patients with inflammatory arthritis. The medications were reclassified as class C controlled substances in the United Kingdom in 2018.

The National Institute for Health and Care Research funded the study, which included input from public contributors regarding pain medication research in inflammatory arthritis management. Potential conflict of interest disclosures can be found in the study.