In recent decades, the rates of incident acute myocardial infarction (AMI) have declined in the United States, yet disparities by sex remain. In an integrated healthcare delivery system, we examined temporal trends in incident AMI among women and men.
We identified hospitalized AMI among members ≥35 years of age in Kaiser Permanente Southern California. The first hospitalization for AMI overall, and for ST-segment-elevation MI and non-ST-segment-elevation MI was identified by International Classification of Diseases, Ninth Revision, Clinical Modification primary discharge diagnosis codes in each calendar year from 2000 through 2014. Age- and sex-standardized incidence rates per 100 000 person-years were calculated by using direct adjustment to the 2010 US Census population. Average annual percent changes (AAPCs) and period percent changes were calculated, and trend tests were conducted using Poisson regression.
We identified 45 331 AMI hospitalizations between 2000 and 2014. Age- and sex-standardized incidence rates of AMI declined from 322.4 (95% CI, 311.0-333.9) in 2000 to 174.6 (95% CI, 168.2-181.0) in 2014, representing an AAPC of -4.4% (95% CI, -4.2 to -4.6) and a period percent change of -46.6%. The AAPC for AMI in women was -4.6% (95% CI, -4.1 to -5.2) between 2000 and 2009 and declined to -2.3% (95% CI, -1.2 to -3.4) between 2010 and 2014. The AAPC for AMI in men was stable over the study period (-4.7% [95% CI, -4.4 to -4.9]). The AAPC for ST-segment-elevation MI hospitalization overall was -8.3% (95% CI, -8.0% to -8.6%).The AAPC in ST-segment-elevation MI changed among women in 2009 (2000-2009: -10.2% [95% CI, -9.3 to -11.1] and in 2010-2014: -5.2% [95% CI, -3.1 to -7.3]) while remaining stable among men (-8.0% [95% CI, -7.6 to -8.4]). The AAPC for non-ST-segment-elevation MI hospitalization was smaller than for ST-segment-elevation MI among both women and men (-1.9% [95% CI, -1.5 to -2.3] and -2.8% [95% CI, -2.5 to -3.2], respectively).
These results suggest that the incidence of hospitalized AMI declined between 2000 and 2014; however, declines in AMI have slowed among women in comparison with men in recent years. Determining unmet care needs among women may reduce these sex-based AMI disparities.