(P-458) Health-related Quality of Life in Older Adults with Concomitant Opioid and Skeletal Muscle Relaxant Use in a National Cohort of Older Adults

Background: Some skeletal muscle relaxants (SMRs) have anticholinergic effects, which can cause cognitive impairment and falls, according to Beers List. Opioid and SMR use has increased in older adults, but knowledge about health-related quality of life (HRQoL) of concomitant use is limited.

Objectives: This study examined determinants of concomitant use and the impact of concomitant use on HRQoL in older adults.

Methods: Cross-sectional analysis used nationally representative 2016 and 2018 Medical Expenditure Panel Survey (MEPS) in the USA (N=8,976 older adults > 65 years). Opioid and SMR use was identified through Multum therapeutic class codes. MEPS administers HRQoL as a mail-in SF12-V2 survey that evaluates mental and physical health (0-100 with higher scores indicating higher well-being). Multivariable logistic regressions were used to examine participant characteristics and the relationship between HRQoL and concomitant use of opioids and SMRs.

Results: Of 8,976 older adults with prescription medication use, 7,182 (80%) were taking opioids alone, 1,372 (15.4%) SMRs alone, 200 (2.23%) were taking opioids and SMRs concomitantly, and 222 (2.3%) were not taking any opioids or SMRs. Concomitant users were more likely to be women, between 65-69 years old, White, and suffered from arthritis and depression. Concomitant opioid and SMR users had a mean unadjusted physical component summary score of 49.01 and was significantly associated with poorer physical health when compared to non-users even after adjustment of sociodemographic and clinical factors. The mean unadjusted mental component summary score for concomitant users was 34.41 compared to 37.09 in opioid-only users, 42.05 in SMR-only users, and 44.6 in non-users. When compared to opioid-only and non-users, concomitant users reported significantly poorer mental health, and this remained significant after adjusting for gender, age, race, income level, education, and comorbidities (P = 0.006).

Conclusions: A small number of older adults are taking concomitant opioids and SMRs. However, concomitant users have significantly poorer mental health compared to non-users and opioid-only users. Opioid use is the strongest contributor to poor physical health with or without SMRs. SMRs and opioids increase fall risk, which can lead to poor mental and physical health. Programs and interventions that promote health are needed to restrict utilization or duration of concomitant use among older adults, as concomitant use may compound mental health issues in older adults. Future studies will evaluate specific concomitant use outcomes like falls, hospitalizations, and death.