Mild behavioral impairment is longitudinally associated with frailty in very old adults with MCI: insights from COGFRAIL.

BACKGROUND: The link between two often overlapping entities: mild behavioral impairment (MBI) and frailty has not been fully understood. AIM: We aimed to investigate the longitudinal association between MBI and frailty. METHODS: Secondary analysis of COGFRAIL (clinicaltrials.gov NCT03129269). Real-life participants from the Toulouse Frailty Clinic with mild cognitive impairment were followed up for two years. MBI was measured using the NPI-Q. Frailty was defined by gait speed (GS) and Fried’s phenotype. We used mixed-effects models to analyse the longitudinal change in gait speed according to the presence and severity of MBI domains, and we examined the risk of incident frailty according to MBI status, using Cox models. RESULTS: n = 234, mean age 83 SD ± 5.3, 58% (n = 135) were pre-frail at baseline. 12% were MBI-free. Participants with decreased motivation at baseline had a steeper decline in GS (p = 0.037), with higher severity directly associated with steeper decline (2-year mean decline of -0.047 m/s, 95% CI -0.092; -0.002). Similar results were found for the abnormal perception domain (2-year mean decline of -0.093 m/s, 95% CI: -0.155 to -0.032). Each higher severity points for decreased motivation at baseline resulted in a 33% higher risk of incident frailty than their counterparts over a mean follow-up of 284 days (SD 346), if measured at baseline HR = 1.33, (95% CI 1.07; 1.66), and as a time-varying variable HR = 1.39 (IC 95% 1.12; 1.72). CONCLUSIONS: The MBI domains of decreased motivation and abnormal perception were longitudinally associated with a steeper decline in gait speed, and decreased motivation predicts incident frailty.