Socioeconomic inequity in incidence, outcomes and care for acute coronary syndrome: A systematic review

Background: Socioeconomic inequities in acute coronary syndrome (ACS) epidemiology and care have been reported for at least 30-40 years. However, an up-to-date overview of evidence reflecting current clinical practice is not available. This systematic review aimed to summarize literature published in the last decade, regarding the association between socioeconomic position (SEP), incidence and prevalence of ACS, post-ACS medical care, and mortality. Methods: The systematic search was performed in PubMed and Embase restricted to publication year (2009-2021), according to predefined methods (PROSPERO: CRD42020197654). Results were classified according to outcomes and socioeconomic exposures, and the risk of bias was evaluated. Results: In total, 181 studies were included, mainly from high-income countries (81%). The majority showed an association between lower SEP (i.e. education, income, occupation, insurance, or composite SEP) and increased ACS incidence (89%)(incidence rate ratios: 1.1-4.7), increased ACS prevalence (88%)(odds ratios (ORs): 1.8-3.9), receiving suboptimal ACS-related medical care (46%)(ORs: 1.1-10.0), or increased post-ACS mortality (71%)(hazard rate ratios: 1.1-4.13). Studies with a lower risk of bias appeared more likely to describe inequity in favor of higher SEP than studies with a higher risk of bias. Conclusions: Across studies from the last decade, lower SEP is associated with higher risks of ACS, subsequent suboptimal medical care, and mortality among the ACS patients, in particular in studies with a lower risk of bias. This indicates considerable socioeconomic inequity among ACS patients internationally, despite low- and middle-low-income countries being inadequately represented. Thus, efforts are warranted to continuously monitor ACS-related socioeconomic inequity.