Acute myocardial infarction (AMI)–related mortality has been decreasing within the United States because of improvements in management and preventive efforts; however, persistent disparities in demographic subsets such as race may exist. In this study, the nationwide trends in mortality related to AMI in adults in the United States from 1999 to 2019 are described. Trends in mortality related to AMI were assessed through a cross-sectional analysis of the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research database. Age-adjusted mortality rates per 100,000 people and associated annual percentage change and average annual percentage changes with 95% confidence intervals (CIs) were determined. Joinpoint regression was used to assess the trends in the overall, demographic (gender, race/ethnicity, age), and regional groups. Between 1999 and 2019, a total of 3,655,274 deaths related to AMI occurred. In the overall population, age-adjusted mortality rates decreased from 134.7 (95% CI 134.2 to 135.3) in 1999 to 48.5 (95% CI 48.3 to 48.8) in 2019 with an average annual percentage change of −5.0 (95% CI −5.5 to −4.6). Higher mortality rates were seen in Black individuals, men, and those living in the South. Patients older than 85 years experienced substantial decreases in mortality. In addition, rural counties had persistently higher mortality rates in comparison with urban counties. In conclusion, despite decreasing mortality rates in all groups, persistent disparities continued to exist throughout the study period.
Acute myocardial infarction (AMI) is one of the leading causes of death within the United States. Over the past 2 decades, there have been numerous advances in AMI care, including prompt and increasing use of early reperfusion with primary percutaneous coronary intervention (PCI), development of newer and potent antiplatelet therapy, and designing systems of care management, that have resulted in improvement of overall AMI mortality. Despite these advances, important disparities in AMI-related mortality in demographic and regional groups persist. Therefore, a detailed assessment of mortality trends within these groups is imperative to improve outcomes, especially within underserved populations. However, much of the existing literature regarding AMI-related mortality relies on hospitalization-related case fatality rates and does not include deaths occurring outside the inpatient setting. Therefore, we used a nationwide database consisting of death certificates to examine demographic and regional disparities in death rates related to AMI from 1999 to 2019 within the United States.
Methods
Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) was used to identify AMI-related deaths occurring within the United States. The Multiple Cause-of-Death Public Use Record and the CDC WONDER database death certificate records were analyzed to determined AMI-related cause of death as a contributing cause on nationwide death certificate records. This database has been previously used in several other studies to analyze nationwide trends in mortality of cardiovascular diseases (CVDs). AMI-related mortality was identified using the International Classification of Diseases, 10th Revision, Clinical Modification codes I21.0, I21.1, I21.2, I21.3, I21.9, I22.0, I22.1, I22.8, and I22.9 in patients ≥25 years. This age restriction was selected because AMI is infrequent in patients <25 years. The study was exempt from institutional review board approval because of the CDC WONDER database containing anonymized, publicly available data.
We extracted data regarding AMI-related deaths and population sizes from 1999 to 2019. Data on demographic and regional groups were extracted, including gender, race/ethnicity, age, urban-rural classification, region, and states. Racial/ethnicity groups were defined as non-Hispanic (NH) White, NH Black, NH American Indian/Alaskan Native, NH Asian/Pacific Islander, and Hispanic people as identified on death certificates. Age groups were defined as 25 to 39, 40 to 54, 55 to 69, 70 to 84, 85+ years of age. For urban-rural classifications, the National Center for Health Statistics Urban-Rural Classification Scheme was used to divide the population into urban (large metropolitan area [population ≥1 million], medium/small metropolitan area [population 50,000 to 999,999]) and rural (population <50,000) counties per the 2013 United States census classification. Regions were classified into Northeast, Midwest, South, and West according to the Census Bureau definitions. Location of death included medical facilities (outpatient, emergency room, inpatient, death on arrival, or status unknown), home, hospice, and nursing home/long-term care.
AMI-related crude and age-adjusted mortality rates AMI were calculated. Crude mortality rates were calculated by dividing the number of AMI-related deaths by the corresponding United States population. AAMR were standardized using the 2000 United States standard population as previously described. The Joinpoint Regression Program (Joinpoint version 4.9.0.0 available from National Cancer Institute, Bethesda, Maryland) was used to determine trends in mortality within the study period. This program identifies significant changes in annual mortality trends over time through Joinpoint regression, which fits models of linear segments where significant temporal variation occurred. Annual percentage change (APC) with 95% confidence intervals (CIs) for the AAMRs were calculated for the line segments linking a Joinpoint using the Monte Carlo permutation test. The weighted average of the APCs were calculated and reported as AAPCs and corresponding 95% CIs as a summary of the reported mortality trend for the entire study period. APC and AAPCs were considered increasing or decreasing if the slope describing the change in mortality over the time interval was significantly different from zero using 2-tailed t test. Statistical significance was set at p ≤0.05.
Results
Between 1999 and 2019, a total of 3,655,274 deaths because of AMI occurred in the overall study population ( Supplementary Table 1 ). Of 3,537,000 deaths with available information on place of death, 39.4% occurred outside of medical facilities (13.8% nursing home/long-term care, 0.9% hospitals, 24.7% home) ( Supplementary Table 2 ).
Overall, the AAMR decreased from 134.7 (95% CI 134.2 to 135.3) in 1999 to 48.5 (95% CI 48.3 to 48.8) in 2019 with an AAPC of −5.0 (95% CI −5.5 to −4.6) ( Supplementary Table 3 ). The APC in AAMR was −4.1 (95% CI −5.8 to −2.4) from 1999 to 2002, which then accelerated to −6.6 (95% CI −7.7 to −5.5) from 2002 to 2007 and subsequently decelerated to −4.2 (95% CI −4.7 to −3.6) from 2007 to 2015 and accelerated to −5.3 (95% CI −6.7 to −3.9) from 2015 to 2019 ( Figure 1 ).
In men, the AAMR decreased from 176.4 (95% CI 175.4 to 177.5) in 1999 to 65.4 (95% CI 65.4 to 64.9) in 2019, with an AAPC of −4.8 (95% CI −5.1 to −4.4) ( Supplementary Table 3 ). The APC in AAMR was −4.4 (95% CI −6.0 to −2.8) from 1999 to 2002, which then accelerated to −6.5 (95% CI −7.6 to −5.5) from 2002 to 2007 and subsequently decelerated to −4.2 (95% CI −4.4 to −3.9) from 2007 to 2019 ( Figure 1 ).
In women, the AAMR decreased from 104.4 (95% CI 103.8 to 105.0) in 1999 to 34.6 (95% CI 34.3 to 34.9) in 2019 with an AAPC of −5.4 (95% CI −5.9 to −4.9) ( Supplementary Table 3 ). The APC in AAMR was −4.0 (95% CI −5.8 to −2.2) from 1999 to 2002, which then accelerated to −6.8 (95% CI −8.0 to −5.6) from 2002 to 2007 and subsequently decelerated to −4.7 (95% CI −5.3 to −4.1) from 2007 to 2015 and accelerated to −6.4 (95% CI −7.9 to −4.8) from 2015 to 2019 ( Figure 1 ).
NH Black people had the highest AAMR, which decreased from 162.4 (95% CI 160.4 to 164.5) in 1999 to 58.5 (95% CI 57.5 to 59.4) in 2019 with an AAPC of −5.0 (95% CI −5.4 to −4.7) ( Supplementary Table 4 ). The APC in AAMR was −2.8 (95% CI −4.2 to −1.4) from 1999 to 2002, which accelerated to −6.9 (95% CI −7.8 to −6.0) from 2002 to 2007 and decelerated to −4.8 (95% CI −5.0 to −4.6) from 2007 to 2019 ( Figure 2 ).
Followed by NH Black people, NH White people had the second highest AAMR, which decreased from 134.7 (95% CI 134.1 to 135.3) in 1999 to 50.1 (95% CI 49.8 to 50.4) in 2019 with an AAPC of −4.9 (95% CI −5.3 to −4.4) ( Supplementary Table 2 ). The APC in AAMR was −4.2 (95% CI −5.9 to −2.6) from 1999 to 2002, which accelerated to −6.5 (95% CI −7.6 to −5.3) from 2002 to 2007, decelerated to −3.9 (95% CI −4.4 to −3.3), and then accelerated to −5.2 (95% CI −6.7 to −3.8) ( Figure 2 ). NH American Indian and Alaskan Native people had the lowest APC at −4.2 (95% CI −4.6 to −3.9).
Patients older than 85 years had the highest crude mortality rate, which decreased from 1,575.7 (95% CI 1,563.6 to 1,587.7) to 492.1 (95% CI 486.7 to 497.4) from 1999 to 2019 with a marked reduction in mortality at an AAPC of −5.7 (95% CI −6.3 to −5.1) ( Figure 3 , Supplementary Table 5 ). Similarly, all other age groups experienced decreases in mortality; however, those aged 25 to 39 and 40 to 54 years had the least reduction in mortality with AAPCs of −2.5 (95% CI −2.8 to 2.2) and −2.7 (95% CI −3.0 to −2.4) throughout the study period.
The average AAMRs were higher in rural counties at 113.6 (95% CI 113.4 to 113.9) than urban (large metropolitan: 71.1 [95% CI 71.0 to 71.2], medium/small metropolitan: 79.6 [95% CI 79.4 to 79.7]) counties. AMI-related mortality decreased in all 3 categories; however, rural counties had the least reduction in mortality at an AAPC of −3.9 (95% CI −4.4 to −3.4) compared with −4.7 (95% CI −5.2 to −4.2) for medium/small metropolitan counties and −5.6 (95% CI −6.0 to −5.2) for large metropolitan counties ( Figure 4 , Supplementary Table 6 ).
