A recent JAMA study, titled ”Differences in Treatment Patterns and Outcomes of Acute Myocardial Infarction for Low- and High-Income Patients in 6 Countries”, Bruce E. Landon, MD, MBA; Laura A. Hatfield, PhD; Gabe Weinreb, BA, and co-authors examined how treatment for an acute heart attack varies for high and low income patients across 6 countries with advanced healthcare systems. Analyzing population-representative, patient-level, administrative data, they found that mortality rates for acute myocardial infarction (MI) rates were consistently higher for low-income patients across the six high income countries surveyed.

The study used administrative claims to identify adults aged 66 years or older who were hospitalized with a primary diagnosis of ST-segment elevation myocardial infarction (STEMI) or non-STEMI between January 2013- December 2018. They excluded patients who had acute MI admission the previous year as well as patients with less than a year of preadmission or postadmission follow-up data, except in case of death. The study recorded demographic information and comorbidities using the Manitoba adaptation of the Elixhauser comorbidity index.

Results showed that among the 289 376 patients hospitalized with (STEMI) and 843 046 hospitalized with non-STEMI across six health systems, the adjusted 30-day and 1-year mortality rates were higher for low-income patients, whereas rates of cardiac catheterization and percutaneous coronary interventions were lower, particularly for those admitted with an NSTEMI, for which care paths are less well delineated. High-income patients also had shorter length of stay and lower rates of readmissions.

These results suggest that income-based disparities were present even in countries with universal health insurance and robust social safety net systems challenging the belief that disparities in health and healthcare are larger in the US that in other high-income countries. Thus, the findings suggest that populations in all countries are subject to the effects of poverty and disadvantage irrespective of history, culture, healthcare system and social safety net.

The study faced several limitations, such as lack of detailed clinical information, disparate methods for identifying income level in various countries, variable race and ethnicity data, age restriction, and varying hospital quality.