The Pooled Cohort Equations for Predicting Risk of Myocardial Infarction and Stroke: Validated in Representative Natural History Populations

Temporal trends in atherosclerotic cardiovascular disease risk among U.S. adults. Analysis of the National Health and Nutrition Examination Survey, 1999-2018

BACKGROUND

Atherosclerotic cardiovascular diseases are a significant cause of disability and mortality. Study of trends in cardiovascular risk at a population level helps understand the overall cardiovascular health and the impact of primary prevention efforts.

AIMS

To assess trends in the estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk among U.S. adults from 1999-2000 to 2017-18 with no established cardiovascular disease (CVD).

METHODS AND RESULTS

Serial cross-sectional analysis of National Health and Nutrition Examination Survey (NHANES) data from 1999-2000 to 2017-18 (10 cycles), including 24 022 US adults aged 40-79 years with no reported ASCVD. ASCVD risk was assessed using the pooled cohort equations (PCEs). There was a significant temporal decline in the mean 10-year ASCVD risk from 13.5% (95% CI, 12.5-14.4) in 1999-2000 to 11.1% (10.5-11.7) in 2011-12 (Ptrend < 0.001) and to 12.0% (11.3-12.7) in 2017-2018 (overall Ptrend = 0.001), with the mean ASCVD risk score remaining stable from 2013-14 through 2017-2018 (Ptrend = 0.056). A declining trend in ASCVD risk was noted in females, non-Hispanic Blacks and those with income <3 times the poverty threshold with Ptrend of <0.001, 0.002, and 0.007, respectively. Mean total cholesterol and prevalence of smokers showed a downward trend (Ptrend <0.001 for both), whereas type 2 diabetes and mean BMI showed an upward trend (Ptrend < 0.001 for both).

CONCLUSIONS

The 20-year trend of ASCVD risk among NHANES participants 40-79 years, as assessed by the use of PCE, showed a non-linear downward trend from 1999-2000 to 2017-18. The initial and significant decline in estimated ASCVD risk from 1999-2000 to 2011-12 subsequently stabilized, with no significant change from 2013-14 to 2017-18. Mean BMI and prevalence of diabetes mellitus increased while mean serum cholesterol levels and prevalence of smoking declined during the study period. Our findings support invigoration of efforts aimed at prevention of CVD, including primordial prevention of CVD risk factors.

Performance of the Atherosclerotic Cardiovascular Disease Pooled Cohort Risk Equations by Social Deprivation Status

BACKGROUND

The atherosclerosis cardiovascular disease (ASCVD) Pooled Cohort risk equations have shown different calibration across US populations with varied levels of social deprivation.

METHODS AND RESULTS

We analyzed the calibration and discrimination of the Pooled Cohort risk equations by social deprivation status among 9066 REGARDS (REasons for Geographic And Racial Differences in Stroke) study participants not taking statins for whom ASCVD risk may lead to statin initiation. Patients were aged 45 to 79 years, had no ASCVD or diabetes mellitus, and had a low-density lipoprotein cholesterol level 70 to 189 mg/dL. Social deprivation was defined using 3 indicators: annual household income <$25 000, less than a high school education, and living without a partner. At baseline in 2003-2007, 54.6%, 27.4%, and 18.0% of participants had 0, 1, and 2 or 3 indicators showing deprivation, respectively. From baseline through December 2012, 457 participants developed ASCVD (nonfatal/fatal stroke, myocardial infarction, or coronary heart disease death). Predicted and observed ASCVD incidence per 1000 person-years were 8.02 and 6.23 (95% CI, 5.31-7.31), respectively, among participants with 0 indicators of deprivation (Hosmer-Lemeshow P=0.01); 8.05 and 6.61 (95% CI, 5.29-8.24), respectively, with 1 indicator (P=0.09); and 9.83 and 11.40 (95% CI, 9.23-14.05), respectively, with 2 or 3 indicators (P=0.12). The C-index (95% CI) was 0.72 (0.69-0.75), 0.73 (0.69-0.78), and 0.70 (0.65-0.75) among participants with 0, 1, and 2 or 3 indicators of deprivation, respectively. The net reclassification improvement after adding deprivation data to the Pooled Cohort risk equations was modest (0.12; 95% CI, 0.03-0.21).

CONCLUSIONS

The Pooled Cohort risk equations have good calibration among individuals with social deprivation but overestimate ASCVD risk among those with less social deprivation.