In The Heart Of The Sea (2015)

[Brigitta Martini]

ProblemCondition: Heart disease is the leading cause of death in the United States. In 2015, heart disease accounted for approximately 630,000 deaths, representing one in four deaths in the United States. Although heart disease death rates decreased 68% for the total population from 1968 to 2015, marked disparities in decreases exist by race and state.

At the national level, heart disease death rates for blacks and whites were similar at the start of the study period (1968) but began to diverge in the late 1970s, when rates for blacks plateaued while rates for whites continued to decrease. Heart disease death rates among blacks remained higher than among whites for the remainder of the study period. Nationwide, the black-white ratio of heart disease death rates increased from 1.04 in 1968 to 1.21 in 2015, with large increases occurring during the 1970s and 1980s followed by small but steady increases until approximately 2005. Since 2005, modest decreases have occurred in the black-white ratio of heart disease death rates at the national level. The majority of states had increases in black-white mortality ratios from 1968 to 2015. The number of states with black-white mortality ratios >1 increased from 16 (40%) to 27 (67.5%).

Interpretation: Although heart disease death rates decreased both for blacks and whites from 1968 to 2015, substantial differences in decreases were found by race and state. At the national level and in most states, blacks experienced smaller decreases in heart disease death rates than whites for the majority of the period. Overall, the black-white disparity in heart disease death rates increased from 1968 to 2005, with a modest decrease from 2005 to 2015.

Public Health Action: Since 1968, substantial increases have occurred in black-white disparities of heart disease death rates in the United States at the national level and in many states. These increases appear to be due to faster decreases in heart disease death rates for whites than blacks, particularly from the late 1970s until the mid-2000s. Despite modest decreases in black-white disparities at the national level since 2005, in 2015, heart disease death rates were 21% higher among blacks than among whites. This study demonstrates the use of NVSS data to conduct surveillance of heart disease death rates by race and of black-white disparities in heart disease death rates. Continued surveillance of temporal trends in heart disease death rates by race can provide valuable information to policy makers and public health practitioners working to reduce heart disease death rates both for blacks and whites and disparities between blacks and whites.

Heart disease is the leading cause of death in the United States (1). In 2015, heart disease accounted for approximately 630,000 deaths, representing one in four deaths (1). Nationally, racial disparities in heart disease mortality have persisted since at least the 1980s (2) and have been documented as the leading contributor to differences between blacks and whites in life expectancy (3). The National Academy of Medicine (NAM), formerly known as the Institute of Medicine, and Healthy People 2020 have both called for increased understanding of health disparities by race and geographic area (4,5). NAM has called for surveillance systems that can measure disparities in heart disease by race and by contextual factors such as place of residence (4). Documenting trends in heart disease death rates by race and state provides valuable information to policy makers and public health practitioners for promoting continued decreases both for blacks and whites, along with decreases in disparities between blacks and whites, in heart disease mortality.

Annual age-standardized heart disease death rates were calculated using statistical software at the national level, by state, and for the District of Columbia (DC) from 1968 to 2015. State-level heart disease death rates can be statistically unreliable when based on small numbers; therefore, heart disease death rates were not calculated for specific state-race groups with

The ratio of black-white heart disease death rates was examined over time. To estimate the standard error of the ratio, the age-standardized rates were assumed to be normally distributed, and the variance of the ratio was computed using the delta method. Using the standard errors of the ratios, 95% confidence intervals (CIs) were calculated. Black-white mortality rate ratios with CIs that include 1 represent approximately equal rates of heart disease deaths among blacks and whites. Ratios with upper CIs 1 indicate higher heart disease death rates among blacks than whites. A relative measure of disparity was used to estimate black-white disparities in heart disease mortality to standardize the change over time in disparities across states (18).

Joinpoint regression was used to model heart disease death rate trends and black-white heart disease mortality ratio trends over time. The program fits a model and uses permutation tests to determine statistically significant changes in temporal trends, identifying the joinpoint (i.e., point at which the slope of the trend line changes). For the total population and by race for each state and nationwide, the annual percentage change (APC) for each joinpoint trend segment and the average annual percentage change (AAPC) for the trend for the entire study period were calculated. Trends were modeled using a log linear model, and the modified Bayesian information criterion (19) was used to detect statistically significant changes in trends. Statistical significance was set at p

Nationally, the black-white mortality ratio increased from the late 1970s to the mid-2000s (Figure 2). The black-white mortality ratio peaked in 2005 (1.31), followed by a modest decrease to 1.21 in 2015. The recent decrease in the black-white ratio reflects a larger rate decrease among blacks than whites during that period. Overall, the black-white disparity in heart disease death rates increased 16.3% from 1968 to 2015.

Of the 51 geographic areas (50 states and DC), 39 states and DC had sufficient numbers of heart disease deaths among blacks to calculate statistically reliable heart disease death rates. All 51 geographic areas had sufficient numbers among whites. In 1968, heart disease death rates for blacks ranged from 562.3 (Minnesota) to 1,601.7 (Rhode Island) per 100,000 population and from 768.1 (New Mexico) to 1,207.2 (Illinois) for whites (Table 2). In 2015, heart disease death rates for blacks ranged from 200.4 (Oregon) to 515.6 (Arkansas) and for whites from 198.1 (DC) to 446.3 (Oklahoma) (Table 2). Both for blacks and whites, the geographic pattern of heart disease death rates changed over time. In 1968, the highest rates for blacks were concentrated primarily in the mid-Atlantic states, along with several midwestern and northeastern states, and the highest rates for whites were concentrated primarily in the Northeast and parts of the Midwest (Figure 3). In 2015, the highest rates for blacks were concentrated primarily in the northeastern, midwestern, and southern states, and the highest rates for whites were concentrated primarily in the south-central states. Comparison of U.S. maps showing heart disease death rates among blacks and whites in 2015 indicates that among blacks, a total of 23 of the state rates were in the highest quartile (based on the joint distribution of rates for blacks and whites), whereas among whites, a total of 11 of the state rates were in the highest quartile.

The black-white patterns for some states were similar to those at the national level; heart disease death rates for blacks were the same as for whites in 1968 but then diverged, with blacks having slower decreases and higher rates than whites for the remainder of the study period. For most states, the black-white mortality ratio increased from 1968 to 2015; however, in Massachusetts and Rhode Island, the ratio decreased; in some states, little change occurred. In 1968, black-white mortality ratios ranged from 0.64 in Minnesota to 1.38 in Rhode Island, and in 2015 they ranged from 0.69 in Rhode Island to 2.42 in DC (Table 3).

This report documents historical trends in black-white disparities in heart disease mortality, along with the total and race-specific trends in heart disease death rates, at both the national and state levels from 1968 to 2015. Nationally, although heart disease death rates decreased for the total population, the patterns of decrease differed by race and state. Heart disease death rates among blacks and whites decreased at comparable rates during the early portion of the study (1968 until the late 1970s) but then diverged from the late 1970s until the mid-2000s. During this time, whites experienced steady decreases in heart disease death rates. Blacks also experienced decreases; however, the rate of decrease was consistently slower than that for whites. This produced an increase in the black-white heart disease mortality ratio of 26% from 1.04 in 1976 to a peak of 1.31 in 2005, which was followed by a modest decrease in the black-white ratio of 7.6% to 1.21 in 2015. Overall, the black-white heart disease mortality ratio increased 16% from 1968 to 2015. At the state level, the majority of states experienced diverging trends in heart disease death rates by race and increases in black-white mortality ratios from 1968 to 2015; however, variations occurred among the states (Supplementary Figures, ) in the direction and magnitude of black-white disparities over time.

Factors contributing to national decreases in heart disease mortality in the United States are estimated to be approximately equally attributable to prevention and advances in treatment (21,22). From 1980 to 2000, approximately half of the reduction of coronary heart disease deaths in the United States was reported to be attributed to improvements in medical treatment, such as antihypertensive medications, cholesterol-lowering drugs, and revascularization for chronic angina (21). The other 50% of the decrease in heart disease deaths was reported to be a function of improvements in risk factors related to heart disease (e.g., reductions in cigarette smoking, hypertension, hyperlipidemia, and physical inactivity) (20,21). Black-white differences in the magnitude and patterns of decrease in heart disease death rates observed in this report suggest that blacks have not benefitted equally from the improvements in prevention and treatment that have contributed to the overall decreases in heart disease deaths in the United States. Specifically, differential or delayed access to or adoption of heart disease prevention and treatment across time among blacks compared with whites could be contributing to the observed increases in black-white disparities (23). In recent years, the modest improvements in the black-white heart disease mortality ratio coincide with a leveling off of decreases both for blacks and whites. This leveling might result from possible slowed progression in the favorable trends of heart disease prevention or treatment along with increases in the prevalence of certain risk factors (e.g., obesity) (21) both for blacks and whites. Additional research is needed to examine the conditions contributing to these patterns.

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