Pooled Cohort Risk Equations for Cardiovascular Risk Prediction in a Multiethnic Cohort From the Women's Health Initiative
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This study of 19,995 women aged 50 to 79 years enrolled in the Women’s Health Initiative evaluated the accuracy of the Pooled Cohort Equations (PCE) for predicting atherosclerotic cardiovascular disease. Over 10 years, 1236 ASCVD events were reported and adjudicated. The observed risks were lower than predicted risks for baseline 10-year risk categories.
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Risks were better aligned after including events ascertained via linkage with CMS claims that were not self-reported.
abstract
This abstract is available on the publisher's site.
Access this abstract nowImportance
Atherosclerotic cardiovascular disease (ASCVD) kills approximately 1 in every 3 US women. Current cholesterol, hypertension, and aspirin guidelines recommend calculating 10-year risk of ASCVD using the 2013 Pooled Cohort Equations (PCE). However, numerous studies have reported apparent overestimation of risk with the PCE, and reasons for overestimation are unclear.
Objective
We evaluated the predictive accuracy of the PCE in the Women's Health Initiative (WHI), a multiethnic cohort of contemporary US postmenopausal women. We evaluated the effects of time-varying treatments such as aspirin and statins, and ascertainment of additional ASCVD events by linkage with the Centers for Medicare and Medicaid Services (CMS) claims.
Design, Setting, and Participants
The WHI recruited the largest number of US women (n = 161 808) with the racial/ethnic, geographic, and age diversity of the general population (1993-1998). For this study, we included women aged 50 to 79 (n = 19 995) participating in the WHI with data on the risk equation variables at baseline and who met the guideline inclusion and exclusion criteria. Median follow-up was 10 years.
Main Outcomes and Measures
For this study, ASCVD was defined as myocardial infarction, stroke, or cardiovascular death.
Results
Among the 19 995 women (mean [SD] age, 64 [7.3] years; 8305 [41.5%] white, 7688 [38.5%] black, 3491 [17.5%] Hispanic, 103 [0.5%] American Indian, 321 [1.6%] Asian/Pacific Islander, and 87 [0.4%] other/unknown), a total of 1236 ASCVD events occurred in 10 years and were adjudicated through medical record review by WHI investigators. The WHI-adjudicated observed risks were lower than predicted. The observed (predicted) risks for baseline 10-year risk categories less than 5%, 5% to less than 7.5%, 7.5% to less than 10%, and 10% or more were 1.7 (2.8), 4.4 (6.2), 5.3 (8.7), and 12.4 (18.2), respectively. Small changes were noted after adjusting for time-dependent changes in statin and aspirin use. Among women 65 years or older enrolled in Medicare, WHI-adjudicated risks were also lower than predicted, but observed (predicted) risks became aligned after including events ascertained by linkage with CMS for additional surveillance for events: 3.8 (4.3), 7.1 (6.4), 8.3 (8.7), and 18.9 (18.7), respectively. Similar results were seen across ethnic/racial groups. Overall, the equations discriminated risk well (C statistic, 0.726; 95% CI, 0.714-0.738).
Conclusions and Relevance
Without including surveillance for ASCVD events using CMS, observed risks in the WHI were lower than predicted by PCE as noted in several other US cohorts, but risks were better aligned after including CMS events.
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Additional Info
Disclosure statements are available on the authors' profiles:
Evaluation of the Pooled Cohort Risk Equations for Cardiovascular Risk Prediction in a Multiethnic Cohort From the Women's Health Initiative
JAMA Intern Med 2018 Jul 23;[EPub Ahead of Print], S Mora, NK Wenger, NR Cook, J Liu, BV Howard, MC Limacher, S Liu, KL Margolis, LW Martin, NP Paynter, PM Ridker, JG Robinson, JE Rossouw, MM Safford, JE MansonFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of death in US women. The 2013 American College of Cardiology (ACC) and American Heart Association (AHA) Pooled Cohort Equations (PCE) estimate 10-year risk of ASCVD in women and men. The most recent ACC/AHA cholesterol and hypertension guidelines recommend using the PCE to inform treatment recommendations and discussions. The controversy with these guidelines includes the argument that the PCE overestimates the risks.
The authors of this study evaluated the accuracy of the PCE predicting a 10-year risk of ASCVD in 19,995 women in the Women’s Health Initiative (WHI), who represented a multi-ethnic cohort of US women, ages 50 to 79. ASCVD included myocardial infarction, stroke, and coronary heart disease (CHD) death. Women were followed over a 10-year period, completing annual self-report questionnaires and having medical records reviewed. Data were expanded for women 65 years and older utilizing Medicare (CMS) claims data, which allowed more validation and inclusion of ASCVD events.
With the inclusion of the CMS data for ASCVD events in this WHI cohort, the ASCVD risk calculated by the PCE was closely aligned with the observable risk. Therefore, the PCE appears to be an effective tool to predict 10-year ASCVD risks in women across ethnic/racial groups. As primary care physicians, the PCE can be an effective tool to inform discussions and treatment decision-making with patients.