Associations Between Polypharmacy and Gait Speed According to Cognitive Impairment Status: Cross-Sectional Study in a Japanese Memory Clinic.

BACKGROUND Polypharmacy, usually defined as the use of 5 or more drugs, is associated with reduced quality of life, adverse events, and frailty. Slow gait speed is a component of physical frailty, and some studies have suggested an association between polypharmacy and slow gait speed. OBJECTIVE We aimed to determine the effects of polypharmacy on the gait difference according to stages of cognitive decline in a cross-sectional study of memory clinic patients. METHODS Participants were 431 outpatients aged 65 year or older who were cognitively normal (CN) or had mild cognitive impairment (MCI) or dementia due to Alzheimer's disease. Participants were divided into a polypharmacy group and a non-polypharmacy group in each group. Multiple regression analysis and logistic analysis were used for data analysis. RESULTS There were 182 patients in the polypharmacy group and 249 patients in the non-polypharmacy group. Multiple regression analysis revealed that gait speed had significant negative associations with number of medications and polypharmacy status in the CN group (β: -0.026 [-0.041 to -0.0018] and -0.128 [-0.022 to -0.0033], respectively) and MCI group (-0.018 [-0.028 to -0.0009] and -0.100 [-0.166 to -0.0034]). Logistic regression analysis also showed that number of medications was associated with slow gait status (< 1 m/s) in the CN group (OR: 1.336 [1.115 to 1.601]) and MCI group (1.128 [1.022 to 1.244]). CONCLUSION CN and MCI patients with polypharmacy have slower gait speed. Attention should be paid to decreased gait speed in older adults with polypharmacy even when their cognitive function is relatively preserved.