Cheng Chen

Title of Research: Risk of fall associated with concomitant use of opioids and gabapentinoids

Additional Authors: A.Winterstein; W.Lo-Ciganic; P.Tighe;Y.Wei


Gabapentinoids are increasingly given with opioids to manage chronic noncancer pain (CNCP) in older adults. When used concomitantly with opioids, gabapentinoids may potentiate central nervous system depression and increase fall risk, but limited population-based studies have investigated this risk. We compared the risk of falls associated with concomitant use of opioids and gabapentinoids versus opioid use alone among older adults with CNCP. Using 5% Medicare data 2011-2018, we identified concomitant users with gabapentinoids and opioids days’ supply overlapping for ≥1 day and designated the 1st day of concomitancy as the index date. We created two cohorts based on whether concomitant users initiated gabapentinoids on day of opioid initiation (cohort 1) or after opioid initiation (cohort 2). Each concomitant user was matched to four opioid-only users on opioid initiation date and index date. In each cohort, we used propensity score weighting and Cox proportional hazard models to calculate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). We identified 6,733 concomitant users and 27,092 matched opioid-only users in cohort 1, and 5,709 concomitant users and 22,388 matched opioid-only users in cohort 2. The aHR for risk of falls among concomitant users versus opioid-only users was 0.99 (95% CI= 0. 71-1.37) in cohort 1 and 1.67 (95% CI=1.16-2.40) in cohort 2, indicating an elevated fall risk among opioid users who added gabapentinoids but similar fall risk when opioids and gabapentinoids were initiated simultaneously. Residual confounding or cohort differences that may modify the effect of concomitant use may explain this discrepancy. Prescribers should heed the risk of falls when prescribing gabapentinoids to older patients who were already taking opioids.


About the author

Cheng ChenCheng “Alice” Chen is a Ph.D. candidate from the Department of Pharmaceutical Outcomes and Policy (POP)Alice received her Bachelor of Science degree in pharmacy from Fudan University in China. In 2015, she joined POP as a Ph.D. student. During her Ph.D. training, Alice has authored and co-authored multiple peer-reviewed publications that focus mainly on chronic pain management and prescription opioid use in older adults. She also obtained a graduate certificate in Aging and Geriatric Practice from College of MedicineHer current research interests include health outcomes of drug-drug interactions, particularly those involving prescription opioid use in the older population. Her dissertation focuses on the Utilization, Safety, and Effectiveness of Prescription Gabapentinoids and Opioids among US Older Adults