Clinical Risk Factors Associated with In-Hospital Frailty Progression in Patients with Cardiovascular Diseases, Including Hemodialysis

Frailty progression during hospitalization is a clinically important outcome in patients with cardiovascular diseases (CVD). However, the factors associated with this deterioration remain insufficiently understood. In particular, renal dysfunction and hemodialysis (HD) may contribute to recovery challenges through mechanisms such as metabolic fluctuations, inflammation, and reduced opportunities for mobilization. Because kidney-related, nutritional, and cardiovascular factors are all interrelated, they should be considered collectively when evaluating in-hospital frailty progression. Therefore, this study aimed to identify clinical risk factors, including HD therapy, associated with frailty worsening during hospitalization in patients with CVD.

This single-center retrospective cohort study included patients hospitalized for CVD who had received in-hospital CR between 2019 and 2022. Patients who died during hospitalization, were unable to ambulate indoors independently before admission, had a hospital stay <6 days, or received CR <4 days were excluded. The primary outcome was a ≥1-point decline in the Clinical Frailty Scale (CFS) from admission to discharge. The secondary outcome was length of hospital days, compared between the CFS-decline and non–CFS-decline groups. The study protocol was approved by the Clinical Research Ethics Committee of Hamamatsu University School of Medicine (approval no. 23-256).Confounding factors were adjusted using three multivariable models: Model 1: age, sex, body mass index (BMI), left ventricular ejection fraction (LVEF), ischemic heart disease, diabetes mellitus, smoking, geriatric nutritional risk index (GNRI), hypertension, atrial fibrillation, and HD therapy; Model 2: Model 1 plus laboratory data and surgical status; Model 3: Model 2 plus pre-admission CFS. Relative risks (RRs) and risk differences (RDs) were calculated with 95% confidence intervals (CIs).

A total of 1,332 patients were analyzed, of whom 530 patients (39.8%) experienced CFS decline. In Model 3, age (RR = 1.02, 95% CI: 1.01–1.03; RD = 0.4%, 95% CI: 0.3–0.6), female sex (RR = 0.83, 95% CI: 0.70–0.97; RD = –3.5%, 95% CI: –6.5 to –0.2), BMI (RR = 1.03, 95% CI: 1.01–1.06; RD = 0.7%, 95% CI: 0.2–1.1), ischemic heart disease (RR = 1.19, 95% CI: 1.01–1.40; RD = 3.7%, 95% CI: 0.1 to 7.9), GNRI (RR = 0.99, 95% CI: 0.98–0.99; RD = –0.4%, 95% CI: –0.5 to –0.3), and HD therapy (RR = 1.61, 95% CI: 1.17–2.22; RD = 12.2%, 95% CI: 3.4–24.3) were independently associated with CFS decline. Length of hospital stay was significantly longer in the decline group (27.2 ± 19.3 vs. 21.2 ± 13.8 days).

In this study of patients hospitalized for CVD and receiving acute-phase CR, an in-hospital decline in CFS was observed in 39.8% of cases. Older age, higher BMI, lower GNRI, ischemic heart disease and HD therapy were independently associated with this decline. These interrelated factors including chronic vulnerability, treatment-related stress, and nutritional imbalance may collectively accelerate frailty progression during hospitalization. Including those on HD, and timely implementation of cardiac rehabilitation may help mitigate further frailty progression and support functional recovery.