Correlation between respiratory muscle weakness and frailty status as risk markers for poor outcomes in patients with cardiovascular disease

Abstract

Aims: Although the developmental mechanism of respiratory muscle weakness (RMW) and frailty are partly similar in patients with cardiovascular disease (CVD), their relationship remains unclear. This study aimed to investigate the correlation between RMW and frailty and its impact on clinical outcomes in patients with CVD. Methods and results: In this retrospective observational study, consecutive 1217 patients who were hospitalized for CVD treatment were enrolled. We assessed frailty status by using the Fried criteria and respiratory muscle strength by measuring the maximal inspiratory pressure (PImax) at hospital discharge, with RMW defined as PImax <70% of the predicted value. The endpoint was a composite of all-cause death and/or readmission for heart failure. We examined the prevalence of RMW and frailty and their correlation. The relationships of RMW with the endpoint for each presence or absence of frailty were also investigated. Respiratory muscle weakness and frailty were observed in 456 (37.5%) and 295 (24.2%) patients, respectively, and 149 (12.2%) patients had both statuses. Frailty was detected as a significant indicator of RMW [odds ratio: 1.84, 95% confidence interval (CI): 1.39-2.44]. Composite events occurred in 282 patients (23.2%). Respiratory muscle weakness was independently associated with an increased incidence of events in patients with both non-frailty [hazard ratio (HR): 1.40, 95% CI: 1.04-1.88] and frailty (HR: 1.68, 95% CI: 1.07-2.63). Conclusions: This is the first to demonstrate a correlation between RMW and frailty in patients with CVD, with 12.2% of patients showing overlap. RMW was significantly associated with an increased risk of poor outcomes in patients with CVD and frailty.