Effects of Prescription Opioid Use on Traumatic Brain Injury Risk in Older Adults

Objective: The objective of this study was to estimate the risk of traumatic brain injury (TBI) associated with opioid use among older adult Medicare beneficiaries. Setting: Five percent sample of Medicare administrative claims obtained for years 2011-2015. Participants: A total of 50 873 community-dwelling beneficiaries 65 years and older who sustained TBI. Design: Case-crossover study comparing opioid use in the 7 days prior to TBI with the control periods of 3, 6, and 9 months prior to TBI. Main Measures: TBI cases were identified using ICD-9 (International Classification of Diseases, Ninth Revision) and ICD-10 (International Classification of Diseases, Tenth Revision) codes. Prescription opioid exposure and concomitant nonopioid fall risk-increasing drug (FRID) use were determined by examining the prescription drug event file. Results: The 8257 opioid users (16.2%) were significantly younger (mean age 79.0 vs 80.8 years, P < .001). Relative to nonusers, opioid users were more likely to be women (77.0% vs 70.0%, P < .001) with a Charlson Comorbidity Index of 2 or more (43.7% vs 30.9%, P < .001) and higher concomitant FRID use (94.0% vs 82.7%, P < .001). Prescription opioid use independently increased the risk of TBI compared with nonusers (OR = 1.34; 95% CI, 1.28-1.40). In direct comparisons, we did not observe evidence of a significant difference in adjusted TBI risk between high- (>= 90 morphine milligram equivalents) and standard-dose opioid prescriptions (OR = 1.01; 95% CI, 0.90-1.14) or between acute and chronic (>= 90 days) opioid prescriptions (OR = 0.93; 95% CI, 0.84-1.02). Conclusions: Among older adult Medicare beneficiaries, prescription opioid use independently increased risk for TBI compared with nonusers after adjusting for concomitant FRID use. We found no significant difference in adjusted TBI risk between high-dose and standard-dose opioid use, nor did we find a significant difference in adjusted TBI risk between acute and chronic opioid use. This analysis can inform prescribing of opioids to community-dwelling older adults for pain management.