An increased risk of heart failure and all-cause mortality was significantly associated with countries which had greater income inequality, even when adjusting for patient-level and socioeconomic variables, according to a study published in JACC: Heart Failure.
The investigators of this study sought to examine the impact of income inequality on heart failure outcomes among different countries.
The study sample included 15,126 patients with heart failure outcomes from 2 large trials conducted across 54 countries. Patients were divided into 3 groups based on tertiles of Gini coefficients, which were used to rank income inequality from 0% (absolute income equality) to 100% (absolute income inequality). Outcomes of interest were the first hospitalization for heart failure or cardiovascular death, and all-cause mortality. Regression models were used to calculate the hazard ratio (HR) for each outcome and were adjusted for region and baseline characteristics. Outcomes were additionally adjusted for socioeconomic variables, including national per capita income, hospital bed density and health worker density per 1000 population, and education index for all countries.
Of 15,126 total patients, 5320 lived in tertile 1 countries (Gini coefficient <33%), 6124 patients lived in tertile 2 countries (Gini coefficient 33% to 41%), and 3772 patients lived in tertile 3 countries (Gini coefficient >41%). Compared with tertile 1 patients, tertile 3 patients were younger, included a higher percentage of women, had fewer comorbidities, and demonstrated a lower prevalence of severe heart failure characteristics. However, tertile 3 patients still had the highest rates of primary composite heart failure outcomes compared with tertile 1 and 2 patients.
After adjusting for conventional prognostic variables, tertile 3 patients remained at significantly higher risk for cardiovascular death or hospitalization for heart failure (HR 1.57; 95% CI, 1.38-1.79) and for all-cause death (HR 1.48; 95% CI, 1.29-1.71). Even after additional adjustments were made for national per capita income, education index, hospital bed density, and health worker density, risk was attenuated but significant in tertile 3 patients for primary composite outcomes (HR 1.46, 95% CI, 1.25-1.7) and all-cause mortality (HR 1.3; 95% CI, 1.1-1.53).
Limitations to the study included a highly selected clinical trial population recruited from specific centers, which may not have fully represented the general population. Individual socioeconomic data were missing, and differences in health care systems among countries were not adjusted for. Finally, the investigators indicate that there was poor representation from Africa in the analysis.
The researchers concluded, “If indeed income inequality does influence HF outcomes, both developing and developed nations need to consider how their public health policies can be modified to more effectively tackle this growing global epidemic.”
Dewan P, Rørth R, Jhund PS, et al. Income inequality and outcomes in heart failure: A global between-country analysis [published online February 4, 2019]. JACC Heart Fail. doi: 10.1016/j.jchf.2018.11.005