The Impact of a Prior Traumatic Brain Injury and Injury Characteristics on Frailty in the Canadian Longitudinal Study on Aging

OBJECTIVE: Using the Canadian Longitudinal Study on Aging (CLSA), we tested the hypothesis that those with a TBI would have increased frailty compared with those without, and we also tested our secondary hypothesis that spending more time unconscious and/or requiring hospitalization following injury is associated with increased frailty. DESIGN: This observational, community-based cohort study uses data from the CLSA (comprehensive cohort). SETTING: Not applicable. PARTICIPANTS: Middle- and older-aged adults at baseline (non-TBI=20,173 [63±10y, 54% female], TBI=6499 [61±9y, 40% female]) and 3-year follow-up were included. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Frailty was measured with a 43-item frailty index (derived from the 65-item CLSA frailty index) and determined as a ratio of deficit present to deficits measured. Participants self-reported TBI outcome information (eg, cause, time unconsciousness, and treatment). Covariate-adjusted linear regressions were conducted by cause of TBI to assess changes in frailty among individuals with a TBI. Time unconscious and treatment were analyzed separately within each cause-of-injury group, compared against those with a TBI who did not fall within the group of interest. RESULTS: Frailty was higher among the TBI group at baseline (means±SD:0.10±0.06) and 3-year follow-up (0.12±0.07) compared with the non-TBI group at baseline (0.09±0.06) and 3-year follow-up (0.11±0.07; all P