Predictors of Composite Clinical Improvement in Heart Failure with Reduced Ejection Fraction: A Retrospective Cohort Study from Bangladesh

Background: Heart failure with reduced ejection fraction (HFrEF) is a major global health challenge, with an increasing burden in low- and middle-income countries despite advances in therapy. Evidence regarding predictors of therapeutic recovery in Bangladeshi populations remains limited. This study aimed to identify independent baseline predictors of composite clinical improvement (CCI) in a large Bangladeshi cohort with HFrEF. Methods: We conducted a retrospective observational cohort study of 1075 adult patients with HFrEF (LVEF < 40%) registered at Continental Hospital in Dhaka, Bangladesh, between January 2020 and December 2024. CCI was defined as achieving at least one of the following at follow-up: ≥30% reduction in N-terminal pro-B-type Natriuretic Peptide, ≥50-meter increase in 6-minute walk distance, or absence of heart failure hospitalization. Independent predictors were identified using multivariable logistic regression with L1-penalized (lasso) variable selection. Results: Among 1075 patients (mean age 58.0 ± 25.1 years; 14.2% female), 503 (46.8%) achieved CCI. Multivariable analysis demonstrated that younger age (odd ratio; OR = 0.91 per 10-year increase, p < 0.001), female sex (OR = 1.28, p < 0.001), and higher body mass index (OR = 1.09 per 5 kg/m² increase, p < 0.001) were independent positive predictors of improvement. The use of Angiotensin Receptor-Neprilysin Inhibitor (ARNI) (OR = 1.42, p < 0.001) and Sodium-Glucose Cotransporter 2 (SGLT2) inhibitors (OR = 1.31, p = 0.002) were independently associated with higher odds of clinical improvement; however, these findings should be interpreted as associations rather than definitive treatment effectiveness, as they are subject to potential confounding by indication in this registry setting. Larger left ventricular end-diastolic diameter (OR = 0.88 per 5 mm increase, p < 0.001), elevated right ventricular systolic pressure (OR = 0.93 per 10 mmHg increase, p = 0.004), ischemic heart disease (OR = 0.66, p < 0.001), and chronic kidney disease (OR = 0.71, p < 0.001) were associated with a lower likelihood of improvement. Conclusions: Our findings support the real-world associations between contemporary HFrEF therapies, including ARNI and SGLT2 inhibitors, and improved clinical outcomes in resource-limited settings. Future prospective research is required to confirm these benefits while accounting for confounding by indication inherent in observational registry data.