Impact of Severe Dyspnea on Mortality and Disability: A 9-Year Cohort Study of Older Adults in Japan

Abstract

Objectives

We investigated the association of severe dyspnea and frailty with all-cause mortality and disability in Japanese community-dwelling older adults.

Design

A 9-year follow-up cohort study.

Setting and Participants

We enrolled 3499 community-dwelling adults aged ≥65 years without disabilities or residence in care facilities who completed a baseline survey in 2013.

Methods

Dyspnea was assessed via a questionnaire on severe dyspnea during daily activities, and frailty status was determined using the Kihon Checklist. Disability was defined as new long-term care insurance certification. Cox proportional hazard models were used to calculate hazard ratios for mortality and disability. Fine-Gray regression models were used to calculate subdistribution hazard ratios for disability while accounting for mortality as a competing risk and adjusting for confounders. Both analyses were stratified by frailty status.

Results

Severe dyspnea was present in 240 participants (6.9%). Overall, the incidence rate of mortality was 6.37 and 2.55 per 100 person-years, and that of disability was 9.96 and 5.06 in the dyspnea and no-dyspnea groups, respectively. Severe dyspnea was associated with a hazard ratio of 1.67 (95% CI, 1.35-2.07) for mortality and 1.38 (95% CI, 1.14-1.67) for incident disability in the frailty group. After accounting for death as a competing risk using the Fine-Gray regression model, the subdistribution hazard ratio for new disability associated with severe dyspnea was 1.38 (95% CI, 1.12-1.70) in the frailty group.

Conclusions and Implications

Severe dyspnea was associated with an increased risk of both mortality and incident disability, particularly among participants in the frailty group. These findings highlight the heightened vulnerability of frail older adults to dyspnea-associated adverse outcomes.