BACKGROUND: Acute myocardial infarction (AMI) is a common presentation of heart disease, the leading cause of mortality in the United States. AMI rates differ by race/ethnicity, and studies examining changes to AMI incidence among diverse adult populations are needed. We examined trends in hospitalized AMI by race/ethnicity during 2000–2014 among Kaiser Permanente Southern California members aged ≥35 years.
METHODS: Hospitalization for AMI each year was identified by using diagnosis codes from hospital discharge records and billing claims. We calculated age- and sex-standardized annual incidence rates by race/ethnicity (Hispanic, non-Hispanic Asian or Pacific Islander, non-Hispanic black [NHB], and non-Hispanic white [NHW]). We estimated incidence rate ratios (IRRs) among race/ethnicity groups by using Poisson regression adjusting for age and sex. We compared trends among race/ethnicity groups by including interaction terms between year (continuous) and race/ethnicity in regression models.
RESULTS: We identified 45,331 AMI hospitalizations during 2000–2014. AMI incidence decreased in each race/ethnicity group (all P <0.001). NHBs, but not other groups, experienced a significantly smaller decline in AMI incidence than NHWs (P = 0.04). During 2000–2014, standardized AMI incidence (per 1,000 person-years) declined from 3.82 (95% confidence interval [CI]: 3.65–3.99) to 1.92 (95% CI: 1.82–2.02) for NHWs and from 3.54 (95% CI: 3.17–3.91) to 2.03 (95% CI: 1.81–2.25) for NHBs. In 2000, NHBs had a lower AMI incidence than NHWs (IRR: 0.90; 95% CI: 0.85–0.96), but 2014 rates were similar (IRR: 1.00; 95% CI: 0.95–1.06).
CONCLUSIONS: AMI hospitalization incidence declined substantially during 2000–2014 for all race/ethnicity groups. Convergence of NHB and NHW AMI incidence rates suggests that disparities have narrowed between these two groups in Southern California.