Impact of traumatic brain injury on recovery over the year following hip fracture among older Medicare beneficiaries

IMPORTANCE: Traumatic brain injury (TBI) is a serious fall-related injury that could occur simultaneously during the fall that resulted in hip fracture. OBJECTIVE: To estimate the impact of TBI on days at home (DAH) among older adults hospitalized with hip fracture. DESIGN: Retrospective cohort study. SETTING: Medicare admisnitrative claims data for years 2010-2017. PARTICIPANTS: Community-dwelling Medicare beneficiaries aged 65 and older and hospitalized with hip fracture 2010-2017. EXPOSURE: TBI was identified during the hospitalization episode using disease classification codes and estimated abbreviated injury scale score codes for the head region. MAIN OUTCOME: DAH was calculated by subtracting the number of days spent in an inpatient, skilled nursing facility, nursing home, emergency department observation, or outpatient observation setting, and the number of days spent deceased, from the total follow-up available for each of the 12 follow-up months (ie, 365 days). MEASURES: We modeled the sum of DAH as a function of TBI using overlap weighting in a Poisson regression model. RESULTS: Among 101 196 Medicare beneficiaries hospitalized with hip fracture between 2010 and 2017, the average age was 83.5 (SD 8.1), 72.7% were female, and 3121 (3.1%) met our criteria for concurrent TBI. Beneficiaries with TBI were older with a higher burden of comorbidities and more likely to die during the 12-month follow-up. Beneficiaries with TBI had fewer DAH after hip fracture (199.7 (SD 140.9) vs 229.7 (SD 133.9), p < .001). Following overlap weighting, TBI was associated with significantly reduced DAH (rate ratio 0.90; 95% confidence interval 0.90, 0.91). CONCLUSIONS: Results suggest that any head injury in the setting of hip fracture may confer meaningful morbidity beyond the already well-documented increases in mortality. RELEVANCE: Future studies should examine whether improved management of TBI would optimize recovery following hip fracture.