Underuse of Guideline-Directed Medical Therapy Across Heart Failure Phenotypes in Older Outpatients: A Multicenter Cross-Sectional Study in Vietnam.

BackgroundHeart failure (HF) is common among older adults; however, data on phenotype distribution and real-world pharmacologic management remain limited. This study assessed the prevalence of guideline-directed medical therapy (GDMT) underuse across HF phenotypes and identified factors associated with GDMT underuse among older outpatients in Vietnam.MethodsIn this multicenter cross-sectional study, 504 outpatients aged ≥60 years with HF were enrolled. Patients were classified into HF with reduced ejection fraction (HFrEF), mildly reduced ejection fraction (HFmrEF), and preserved ejection fraction (HFpEF). HFmrEF and HFpEF were combined as a non-HFrEF group for analysis. Multivariable logistic regression was performed to identify factors independently associated with GDMT underuse.ResultsHFrEF, HFmrEF, and HFpEF accounted for 54.6% (n = 275), 13.3% (n = 67), and 32.1% (n = 162) of patients, respectively. GDMT underuse was observed in 49.8% of patients with HFrEF and 38.0% of those with non-HFrEF phenotypes. In HFrEF, hypertension was associated with lower GDMT underuse (odds ratio [OR] 0.38; 95% confidence interval [CI] 0.15-0.98), whereas chronic obstructive pulmonary disease (COPD) was associated with higher underuse (OR 4.42; 95% CI [1.38-14.2]). In non-HFrEF, diabetes mellitus was independently associated with lower GDMT underuse (OR 0.52; 95% CI [0.30-0.91]).ConclusionIn this study, GDMT underuse was observed in nearly half of patients with HFrEF and over one-third of those with non-HFrEF phenotypes. In HFrEF, hypertension was associated with lower GDMT underuse and COPD with higher GDMT underuse, whereas in non-HFrEF, diabetes mellitus was independently associated with lower GDMT underuse.