Background: The Framingham Risk Score (FRS) and Pooled Cohort Equations (PCEs) overestimate risk in many contemporary cohorts.
Objectives: This study sought to determine if recalibration of these scores using contemporary population-level data improves risk stratification for statin therapy.
Methods: Five-year FRS and PCEs were recalibrated using a cohort of Ontario residents alive January 1, 2011, who were 30 to 79 years of age without cardiovascular disease. Scores were externally validated in a primary care cohort of routinely collected electronic medical record data from January 1, 2010, to December 31, 2014. The relative difference in mean predicted and observed risk, number of statins avoided, and number needed to treat with statins to reduce a cardiovascular event at 5 years were reported.
Results: The FRS was recalibrated in 6,938,971 Ontario residents (51.6% women, mean age 48 years) and validated in 71,450 individuals (56.1% women, mean age 52 years). Recalibration reduced overestimation from 109% to 49% for women and 131% to 32% for men. The recalibrated FRS was estimated to reduce statin prescriptions in up to 26 per 1,000 low-risk women and 80 per 1,000 low-risk men, as well as reduce the number needed to treat from 61 to 47 in women and from 53 to 41 in men. In contrast, after recalibration of the PCEs, risk remained overestimated by 217% in women and 128% in men.
Conclusions: Recalibration is a feasible solution to improve risk prediction but is dependent on the model being used. Recalibration of the FRS but not the PCEs reduced overestimation and may improve utilization of statins.
Competing Interests: Funding Support and Author Disclosures This work was supported by funding from a Foundation Grant (FDN 143313 [to Jack V. Tu]) by the Canadian Institutes of Health Research. Additional funding was provided by another Canadian Institutes of Health Research Foundation Grant (FDN 154333). The funding source had no role in the study's design, conduct, or reporting. Dr Sud is funded by the Eliot Phillipson Clinician-Scientist Program at the University of Toronto, a Canadian Institute of Health Research Post-Doctoral Fellowship, and the SANSAR-Burgundy Young Investigator Award. Dr Austin is supported by a Mid-Career Investigator Award from the Heart and Stroke Foundation. Dr Lee is the Ted Rogers Chair in Heart Function Outcomes, University Health Network, University of Toronto. Dr Roifman is funded by the National New Investigator and Ontario Clinician Scientist Awards by the Heart and Stroke Foundation. Dr Tu receives a research scholar award from the Department of Family and Community Medicine at the University of Toronto. Dr Wijeysundera is supported by a Canada Research Chair in Structural Heart Disease Policy and Outcomes. Dr Ko is supported by the Jack Tu Chair in Cardiovascular Outcomes, Sunnybrook Hospital and University of Toronto. Dr Farkouh has received research grants support from Amgen, Novartis, and Novo Nordisk. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)