Recalibration of the Framingham risk score for predicting 10-year risk of cardiovascular events: A non-concurrent rural cohort study from Tamil Nadu

Abstract

Objective: To recalibrate the Framingham Risk Score-cardiovascular diseases (FRS-CVD) using 10-year mortality data and baseline risk factor data for a rural cohort and assess the effect of recalibration on proportion categorised as high risk.

Methods: Participants of a cardiovascular risk factor survey aged 30-64 years in 2011-12, from 9 villages of a rural block in Vellore, Tamil Nadu, were followed up for mortality till 2021, as part of an established demographic surveillance system. We calculated both lipid-based and Body Mass Index-based FRS-CVD risk scores, as well as recalibrated scores using risk factor data from the baseline survey and CVD mortality observed over 10 years.

Results: Based on original lipid-based FRS-CVD scores, 8.48% (109) of 1285 males had a 10-year CVD risk ≥30%, compared to 11.60% (149) with recalibrated scores. Among 1737 females, 1.50% (26) had a 10-year CVD risk of ≥30%, using original FRS-CVD scores, and 3.22% (56) using recalibrated scores. Similarly, for BMI based FRS-CVD scores, overall, 3.63% (110/3028) had a 10-year risk of ≥30%, compared to 6.64% (201) using recalibrated scores. The median 10-year FRS-CVD original score in males was 7.57 (IQR: 3.67-15.83), and 2.53 (IQR: 1.28-5.32) in females, compared to 8.95 (IQR: 4.35-18.52) and 3.79 (IQR: 1.92-7.93) respectively, for the recalibrated FRS-CVD risk scores.

Conclusion: The recalibrated Framingham models showed a greater proportion of the population at risk of CVDs compared to the original FRS scores, with males having 2-3 times greater CVD risk scores compared to females.

Keywords: CVD risk Score; Cardiovascular diseases; Framingham risk score; Recalibration.