A Cross-Sectional Observational Study：Prevalence and Associated Factors of Frailty in Hospitalized Elderly Patients With Heart Failure

Clinical Frail Scale (CFS) score

时间窗: Baseline

The CFS is assessed through clinical judgment based on a patient's functional status, mobility, activity tolerance, comorbidities, and cognitive function in the preceding two weeks. The scale classifies patients into nine levels based on their degree of frailty: 1 - Very Fit, 2 - Well, 3 - Managing Well, 4 - Vulnerable, 5 - Mildly Frail, 6 - Moderately Frail, 7 - Severely Frail, 8 - Very Severely Frail, and 9 - Terminally Ill. The higher the CFS score, the greater the degree of frailty. Excluding those with scores of 8-9, patients with scores of 0-4 are classified into the non-frail group, while those with scores of 5 or higher are classified into the frail group. Frailty Severity Grading Criteria: Clinical Frailty Scale (CFS) score: non-frail (CFS 0-4), moderate frailty (CFS 5-6), and severe frailty (CFS 7).

brain natriuretic peptide (BNP)

时间窗: Baseline

Assessed using a blood sample analyzed by an immunoassay. This biomarker reflects ventricular wall stress and is widely used for diagnosing and monitoring heart failure. BNP levels are reported in ng/L. According to clinical guidelines, a BNP \<100 ng/L is considered normal in untreated patients; levels \>400 ng/L are strongly suggestive of heart failure, while values between 100 and 400 ng/L are considered intermediate and should be interpreted in the clinical context. Higher BNP levels indicate greater cardiac stress and correlate with worse outcomes.

left ventricular ejection fraction (LVEF) value

时间窗: Baseline

Assessed using echocardiography (transthoracic echocardiography is the standard method), or alternatively by cardiac magnetic resonance imaging or nuclear imaging. This imaging parameter quantifies the percentage of blood ejected from the left ventricle during systole and is the primary measure of systolic function. LVEF is reported as a percentage (%). According to clinical guidelines, a normal LVEF is ≥50%; a mildly reduced LVEF is 40-49%; a moderately reduced LVEF is 30-39%; and a severely reduced LVEF is \<30%. Lower LVEF values indicate worse systolic dysfunction and are associated with increased risk of heart failure and adverse outcomes.