Association of Depressive Mood and Frailty With Mortality and Health Care Utilization: Korean National Cohort Study

To investigate the association of depressive mood and frailty with mortality and health care utilization (HCU) and identify the coexisting effect of depressive mood and frailty in older adults.

A retrospective study using nationwide longitudinal cohort data.

A total of 27,818 older adults age 66 years from the National Screening Program for Transitional Ages between 2007 and 2008, part of the National Health Insurance Service-Senior cohort.

Depressive mood and frailty were measured by the Geriatric Depression Scale and Timed Up and Go test, respectively. Outcomes were mortality and HCU, including long-term care services (LTCS), hospital admissions, and total length of stay (LOS) from the index date to December 31, 2015. Cox proportional hazards regression and zero-inflated negative binomial regression were performed to identify differences in outcomes by depressive mood and frailty.

Participants with depressive mood and frailty represented 50.9% and 2.4%, respectively. The prevalence of mortality and LTCS use in the overall participants was 7.1% and 3.0%, respectively. More than 3 hospital admissions (36.7%) and total LOS above 15 days (53.2%) were the most common. Depressive mood was associated with LTCS use [hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.05-1.42] and hospital admissions [incidence rate ratio (IRR) 1.05, 95% CI 1.02-1.08]. Frailty had associations with mortality risk (HR 1.96, 95% CI 1.44-2.68), LTCS use (HR 4.86, 95% CI 3.45-6.84), and LOS (IRR 1.30, 95% CI 1.06-1.60). The coexistence of depressive mood and frailty was associated with increased LOS (IRR 1.55, 95% CI 1.16-2.07).

Our findings highlight the need to focus on depressive mood and frailty to reduce mortality and HCU. Identifying combined problems in older adults may contribute to healthy aging by reducing adverse health outcomes and the burden of health care costs.