Background: Sarcopenia is a comorbidity associated with heart failure, which aggravates its prognosis. Objectives: To analyze the differential characteristics of polypathological patients with acute heart failure (AHF) based on the presence of low muscle strength, as well as to study whether this condition is associated with a worse prognosis. Methods: An observational study of 377 patients with a diagnosis of acute heart failure from the prospective multicentric PROFUND-IC registry was carried out. The main variable is low muscle strength, which is assessed with dynamometry or prehensile strength. Epidemiological and anthropometric characteristics, as well as associated comorbidities, were analyzed. Likewise, the etiology of the AHF episode, the number of admissions in the previous year, and the NYHA scale were also included. Finally, scores on functionality, treatment established, and mortality and readmission rates were studied. Quantitative variables are described as mean, and standard deviation, and qualitative variables are expressed as absolute numbers and percentages. A descriptive and bivariate analysis was performed according to the presence of low muscle strength (handgrip <27 kg in men and <16 kg in women), using the Welch test for quantitative measures and Chi-square for qualitative variables. In addition, Kaplan-Meier curves of readmission and mortality and a logistic regression analysis were also performed. Results: 377 patients were included (56% female, mean age 83 years). 310 (82.23%) had low muscle strength. Those with low muscle strength were older (84 vs. 78 years, p < 0.001), with more cognitive impairment (11.9% vs. 0%, p = 0.021), worse functional class (p = 0.016), lower scores in the Barthel index and Rockwood scale (p < 0.001), and higher in the PROFUND index (p < 0.001). They had higher rates of readmission and mortality without statistically significant differences. The PROFUND index is significantly associated with low muscle strength (OR 1.19, CI (1.09–1.31), p < 0.001). Conclusions: Elderly polypathological patients with acute heart failure and low muscle strength have a higher PROFUND index and a lower probability of survival per year.

Background/Objectives: Acute heart failure (AHF) is the leading cause of hospitalization among patients over 65 years and is frequently associated with frailty. Sodium-glucose cotransporter type 2 inhibitors (SGLT2i) currently represent the only drug class recommended across the entire ejection fraction spectrum, although evidence regarding their effectiveness according to frailty status remains limited. Aims: To determine whether functional frailty, measured by the Short Physical Performance Battery (SPPB) test, influences the effectiveness of SGLT2i in reducing hospital readmission and mortality in elderly patients with AHF. Methods: Observational study of 794 polypathological patients admitted to Internal Medicine with AHF. An interaction analysis assessed whether SPPB, as a continuous variable, modified the association between SGLT2i and the composite outcome (hospital readmission or death), using a Cox model. The sample was further divided by SPPB test score (below 4 (N = 477) or ≥4 (N = 317)) for exploratory analyses. Descriptive and comparative analyses were performed according to SGLT2i administration, using the chi-squared test for qualitative variables and Student’s t-test for quantitative ones (Fisher’s and Mann–Whitney U test as appropriate). Survival analysis was done using Kaplan–Meier curves and Cox regression, with multivariable adjustment for confounders. Results: No significant interaction was found between SPPB score and SGLT2i (p = 0.506). When SPPB was dichotomised, SGLT2i treatment was associated with significantly lower all-cause mortality (3.7% vs. 12.0%; p = 0.018) and readmission (30.3% vs. 45.2%; p = 0.021) in SPPB ≥ 4, with mortality and readmission also numerically lower, without reaching statistical significance, in SPPB < 4 (mortality 12.9% vs. 16.9%, p = 0.410; readmission 34.5% vs. 42.0%, p = 0.220). After adjustment, SGLT2i treatment in the SPPB ≥ 4 group remained associated with a numerically lower hazard for the composite outcome (HR 0.652; 95% CI 0.418–1.018; p = 0.060). Conclusions: No evidence was found that functional frailty modifies the effectiveness of SGLT2i in elderly polypathological patients with AHF. An exploratory analysis suggested a possible gradient of greater association with SPPB ≥ 4, although this should be interpreted as hypothesis-generating.