Income level and inequality as complement to geographical differences in cardiovascular trials

Area of Science:

• Cardiovascular medicine
• Health economics
• Clinical trial analysis

Background:

• Geographical subgroup analyses in cardiovascular (CV) trials often overlook socioeconomic determinants.
• Country income and income inequality are key indicators of healthcare access and social structure.
• Previous analyses primarily focused on geographical, racial, ethnic, and genetic variations.

Purpose of the Study:

• To investigate the association between national income levels, income inequality, and patient prognosis.
• To analyze these associations in patients with heart failure or acute coronary syndrome.
• To utilize data from three major international cardiovascular trials: EMPHASIS-HF, EPHESUS, and EXAMINE.

Main Methods:

• Countries were categorized as high-income or low-middle income (LMICs).
• Income inequality was assessed using the Gini index (low, middle, or high).
• Primary endpoints were all-cause mortality and cardiovascular death.

Main Results:

• Patients from LMICs and high-inequality countries were younger, less often white, and had fewer comorbidities.
• These patients received guideline-recommended therapies less frequently.
• Higher adjusted mortality rates were observed in LMICs (+15% to +70%) and high-inequality countries compared to high-income, low-inequality nations.
• The combination of low-middle income and high inequality showed the most substantial increase in mortality (+80% to +190%).
• Socioeconomic factors (poverty and inequality) had a greater impact on mortality than individual comorbidities.

Conclusions:

• Low-middle income status and high income inequality are associated with the highest mortality rates in cardiovascular patients.
• The prognostic significance of national income and inequality is substantial.
• These socioeconomic factors must be considered in subgroup analyses of cardiovascular trials to understand outcome disparities.