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

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.

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.

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.

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.