Introduction Few if any studies have been conducted to date on the association between polypharmacy and cognitive impairment among older trauma patients. Therefore, we investigated whether polypharmacy is associated with cognitive impairment in trauma patients aged ≥70 years.

Methods This is a cross-sectional study of patients aged ≥70 years hospitalised due to a trauma-related injury. Cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score ≤24 points. Medications were coded according to the Anatomical Therapeutic Chemical classification. Three exposures were examined: polypharmacy (≥5 medications), excessive polypharmacy (≥10 medications), and number of medications. Separate logistic regression models adjusted for age, sex, body mass index (BMI), education, smoking, independent living, frailty, multimorbidity, depression, and type of trauma were used to test the association between the three exposures and cognitive impairment.

Results A total of 198 patients were included (mean age 80.2; 64.7% women and 35.4% men), of which 148 (74.8%) had polypharmacy and 63 (31.8%) had excessive polypharmacy. The prevalence of cognitive impairment was 34.3% overall, 37.2% in the polypharmacy group and 50.8% in the excessive polypharmacy group. More than 80% of participants were taking at least one analgesic. Overall, polypharmacy was not statistically significantly associated with cognitive impairment (odds ratio (OR) 1.20 [95% confidence interval (CI) 0.46 to 3.11]). However, patients in the excessive polypharmacy group were more than two times more likely to have cognitive impairment (OR 2.88 [95% CI 1.31 to 6.37]) even after adjustments for relevant confounders. Similarly, the number of medications was associated with greater odds of cognitive impairment (OR 1.15 [95% CI 1.04 to 1.28]) after adjustments for the same relevant confounders.

Conclusion Cognitive impairment is common among older trauma patients, particularly among those in the excessive polypharmacy group. Polypharmacy was not associated with cognitive impairment. Excessive polypharmacy and number of medications, on the other hand, were associated with greater odds of cognitive impairment in older trauma patients.