Smoking Outcomes May Improve ASCVD Risk Prediction, Suggests New Analysis

Modifying the 2013 American College of Cardiology/American Heart Association pooled cohort equations (PCE) to include smoking history significantly improved atherosclerotic cardiovascular disease (ASCVD) risk prediction in a new analysis of data from the Framingham Heart Study.

The retrospective analysis was published online December 8, 2021 in JAMA Cardiology.

“Because ASCVD risk increases with greater pack-years smoked and decreases with sustained cessation, ASCVD risk may be misestimated in individuals who have ever smoked heavily,” wrote authors led by Meredith Duncan, PhD, from the University of Kentucky and Vanderbilt University Medical Center.

Duncan and colleagues analyzed data from the Framingham Heart Study and used risk factor definitions from the 2013 PCE models, including age, total cholesterol, high-density lipoprotein, systolic blood pressure, antihypertensive use, current smoking status, and diabetes.

A total of 3908 participants (mean age, 55 years; 51.5% women) who attended their first examination from 1971 to 1975 and followed until December 2016 were included in the analysis. The primary outcome was incident ASCVD, including myocardial infarction, fatal/nonfatal ischemic stroke, coronary heart disease, or death.

Researchers reported 358 incident ASCVD events occurred among men and 197 events among women. Ever-smoking prevalence was high as were median pack-years among men (77% and 39 years, respectively) and women (78% and 32 years, respectively), according to the study.

Investigators built 4 sex-specific ASCVD risk prediction models adjusted for former smoking, pack-years, and years since quitting. The models were compared through C-statistic change, continuous net reclassification improvement (NRI[>0]), and relative integrated discrimination improvement (rIDI).

Among both sexes, there were “significant but modest” improvements in NRI(>0) (men, 0.23; women, 0.34) and rIDI (men, 0.19; women, 0.11) values when adjusted for former smoking, pack-years, and years since quitting compared with the PCE with continuous variables on their natural scale.

“The Framingham Heart Study offspring cohort is largely composed of non-Hispanic White participants of European ancestry. If results are validated in cohorts of race and ethnicity groups other than White, these variables could be considered for inclusion in future ASCVD risk prediction models,” noted researchers.