Validation of the European SCORE2 models in a Canadian primary care cohort

Introduction — SCORE2 was recently developed to predict atherosclerotic cardiovascular disease (ASCVD) in Europe. Whether these models could be used outside of Europe is not known. The objective of this study was to test the validity of SCORE2 in a large Canadian cohort.

Methods — A primary care cohort of persons with routinely collected electronic medical record data from January 1, 2010, to December 31, 2014, in Ontario, Canada was used for validation. The SCORE2 models for younger persons (YP) were applied to 57,409 individuals aged 40 to 69 while the models for older persons (OP) were applied to 9,885 individuals 70 to 89 years of age. Five-year ASCVD predictions from both the uncalibrated and low-risk region recalibrated SCORE2 models were evaluated.

Results — The C-statistic for SCORE2-YP was 0.74 in women and 0.69 in men. The uncalibrated SCORE2-YP overestimated risk by 17% in women and underestimated by 2% in men. In contrast, the low-risk region recalibrated model demonstrated worse calibration, overestimating risk by 100% in women and 36% in men. The C-statistic for SCORE2-OP was 0.64 and 0.62 in older women and men, respectively. The uncalibrated SCORE2-OP overestimated risk by more than 100% in both sexes. The low-risk region recalibrated model demonstrated improved calibration, but still overestimated risk by 60% in women and 13% in men.

Conclusions — The performance of SCORE2 to predict ASCVD risk in Canada varied by age group and depended on whether regional calibration was applied. This underscores the necessity for validation assessment of SCORE2 prior to implementation in new jurisdictions.