(P-485) Predictors of Concomitant Use of Opioids and Gabapentin in the National Alzheimer's Coordinating Center Database

Background: In 2019, opioids and gabapentin were added to the clinically important drug-drug interaction table in the American Geriatric Society Beers Criteria, citing moderate evidence to support the recommendation to avoid concomitant use, yet recognizing the need to balance concerns with treatment of chronic pain. Understanding the characteristics of those on concomitant therapy is important for risk vs. benefit evaluation in older adults.

Objectives: To examine characteristics associated with concomitant use of opioids and gabapentin in older adults in the US.

Methods: We used data from the National Alzheimer’s Coordinating Center Uniform Data Set (NACC UDS) collected between 2005 and 2017, and included participants age ≥65 at enrollment. Concomitant gabapentin and opioid use was identified based on the medication data collected at each visit during follow-up. Multivariable logistic regression with backward selection was used to evaluate demographic characteristics, cognitive status, and medication history at enrollment as potential predictors of concomitant use. The adjusted odds ratio (aOR) and 95% confidence intervals (CI) were estimated.

Results: Of 36,327 participants in NACC, 28,427 were included in our study (mean [SD] age 76.1 [ 7.1], 43.6% male) and 450 (1.6%) reported concomitant gabapentin-opioid use. Of the factors investigated as predictors of concomitant use, several showed a significantly positive association: female sex (aOR = 1.36; 95% CI = 1.11–1.67), black race vs. white (1.77; 1.41-2.23), using ≥10 medications vs. none (5.23; 3.31–8.26), living in group residence vs. private (1.75; 1.30–2.36). Factors negatively associated with concomitant use included: education (ref: high school/GED) college (0.78; 0.62-0.97), graduate (0.65; 0.50-0.83), and dementia diagnosis (0.36; 0.28–0.47).

Conclusions: Overall, concomitant gabapentin-opioid use was low in this population of older adults. Several characteristics including sex, race, type of residence, and number of medications were predictive of concomitant use. Identifying circumstances in which the benefit of concomitant use outweighs the risk is important to minimize harm in vulnerable older adults.