Combined effect of educational attainment and diabetes on 1-year all-cause mortality in heart failure patients: findings from the National Heart Failure Registry, India

Background Patients with coexisting heart failure (HF) and diabetes mellitus are often prescribed complex treatment regimens, which can contribute to adverse clinical outcomes. However, the impact of such therapeutic complexity may be shaped by social determinants of health, particularly educational attainment, which influence patients’ capacity to engage with and adhere to recommended care. Methods We analysed data from the National Heart Failure Registry (NHFR), a prospective, multicentre cohort comprising 10 850 consecutively enrolled patients with HF from 53 hospitals across 21 states in India. All the patients were followed up for 1 year. Multivariable Cox proportional hazards models examined the independent association between diabetes mellitus and 1-year all-cause mortality. Analyses were stratified by educational attainment to assess effect modification. An interaction term between diabetes and education was included to evaluate the modifying influence of education on mortality risk. Models were adjusted for demographic, clinical and treatment-related covariates. Findings At 1 year, cumulative all-cause mortality among patients with HF was 22.1%. In adjusted Cox proportional hazards models, diabetes mellitus was associated with a 10% increased risk of all-cause mortality compared with those without diabetes (HR 1.10, 95% CI 1.01 to 1.19). Higher educational attainment was independently associated with reduced mortality risk. Compared with individuals without diabetes and low educational attainment, those with both diabetes and low education had a 25% higher risk of death (HR 1.25, 95% CI 1.08 to 1.44). In contrast, individuals with diabetes and higher education had a 22% lower mortality risk (HR 0.78, 95% CI 0.65 to 0.94). A significant interaction between diabetes and education was observed (p value for interaction <0.05), indicating that educational attainment modifies the association between diabetes and mortality. Interpretation Diabetes and educational attainment are independent predictors of mortality in HF, with a significant interaction indicating that the impact of diabetes is greater among those with lower education. These findings highlight the need to address social determinants of health in HF clinical care. Public health strategies should prioritise health literacy and equitable access to care to reduce disparities and improve outcomes in vulnerable populations.