Association between pre-hip fracture depression and days at home after fracture and assessing sex differences

Background: Hip fracture and depression are important public health issues among older adults, but how pre-fracture depression impacts recovery after hip fracture is unknown, especially among males who often experience greater depression severity. Days at home (DAH), or the days spent outside a hospital or healthcare facility, is a novel, patient-centered outcome that can capture meaningful aspects of fracture recovery. How pre-fracture depression impacts DAH after fracture, and related sex differences, remains unclear.

Methods: Participants included 63,618 Medicare fee-for-service beneficiaries aged 65+ years, with a hospitalization claim for hip fracture surgery between 2010 and 2017. The primary exposure was a diagnosis of depression at hospital admission, and the primary outcome was total DAH over 12 months post-discharge. Longitudinal associations between pre-fracture depression and the count of DAH among beneficiaries were estimated using Poisson regression models after adjustment for covariates; sex-by-depression interactions were also assessed. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) reflecting relative differences were estimated from these models.

Results: Overall, beneficiaries with depression were younger, White females, and spent 11 fewer average DAH compared to counterparts without depression when demographic factors (age and sex) (IRR = 0.91; 95% CI = 0.90, 0.92; p < 0.0001) and social determinants of health (race, Medicaid dual eligibility, and poverty) were adjusted for (IRR = 0.92; 95% CI = 0.91, 0.93; p < 0.0001), but this association attenuated after adjusting for medical complexities (IRR = 0.99; 95% CI = 0.98, 1.01; p = 0.41) and facility and geographical factors (IRR = 1.0037; 95% CI = 0.99, 1.02; p = 0.66). There was no evidence of effect modification by sex.

Conclusions: The comorbidity burden of preexisting depression may impact DAH among both male and female Medicare beneficiaries with hip fracture. Results suggest a holistic health approach and secondary prevention of depressive symptoms after hip fracture.