Association between excess mortality in depressive status and frailty among older adults: A population-based Kyoto-Kameoka prospective cohort study.

OBJECTIVES

Frailty has been shown to be a mediator of the risk of excess death due to depression in older adults, although this relationship has not been sufficiently investigated. Our objective was to evaluate this relationship.

METHODS

We used data from 7,913 Japanese people aged≥65 years who participated in the Kyoto-Kameoka prospective cohort study and who provided valid responses to the Geriatric Depression Scale-15 (GDS-15) and the World Health Organization-Five Well-Being Index (WHO-5) in mail-in surveys. Depressive status was assessed using the GDS-15 and WHO-5. Frailty was evaluated using the Kihon Checklist. Data on mortality were collected from February 15, 2012, to November 30, 2016. We evaluated the relationship between depression and all-cause mortality risk using a Cox proportional-hazards model.

RESULTS

The prevalence of depressive status assessed by GDS-15 and WHO-5 was 25.4% and 40.1%, respectively. In total, 665 deaths were recorded during a median follow-up period of 4.75 years (35,878 person-years). After adjusting for confounders, we found that depressive status assessed by the GDS-15 had a higher risk of mortality than those without it (hazard ratio [HR] 1.62, 95% confidence interval [CI] 1.38-1.91). This association was moderately weaker when adjusted for frailty (HR 1.46, 95% CI 1.23-1.73). Similar results were observed when depression was assessed with the WHO-5.

CONCLUSION

Our findings suggest that the risk of excess death due to depressive status in older adults may be partially explained by frailty. This indicates a need to focus on improving frailty besides conventional depression treatments.