(VP127) VALIDATION OF THE EUROPEAN SCORE2 MODELS IN A CANADIAN PRIMARY CARE COHORT

Background: Canadian guidelines recommend using the Framingham equations in primary prevention assessments. Recent studies have suggested these equations may overestimate risk in contemporary populations. Recently, the SCORE2 models were developed to predict atherosclerotic cardiovascular disease (ASCVD) risk in Europe and have been recalibrated for use in European countries with cardiovascular event rates similar to Canada. Hence, the objective of this study was to test the validity of the SCORE2 models in a large Canadian cohort.

METHODS AND RESULTS: A primary care cohort of routinely collected electronic medical record data from January 1, 2010, to December 31, 2014, in Ontario, Canada was assembled for validation. ASCVD outcomes (myocardial infarction, stroke, and cardiovascular death) were ascertained to December 31, 2018. The 5-year SCORE2 models for younger persons (YP) were applied to individuals aged 40 to 69 while the models for older persons (OP) were applied to individuals 70 to 89 years of age. Both uncalibrated and recalibrated (to a low-risk region such as Canada) SCORE2 models were evaluated. Discrimination was assessed using the C-statistic and calibration was assessed using the relative difference in mean predicted and observed risk.

The validation cohort for SCORE2-YP models consisted of 32,282 women (269 ASCVD events, 5-year incidence 0.84%, 95% CI: 0.74-0.94) and 25,127 men (534 ASCVD events, 5-year incidence 2.15%, 95% CI: 1.97-2.33). The C-statistic was 0.74 in women and 0.69 in men. The uncalibrated SCORE2-YP models demonstrated good calibration with overestimation of 17% in women and underestimation of 2% in men (Figure). In contrast, the low-risk region recalibrated model demonstrated worse calibration and overestimated risk by 100% in women and 36% in men. For individuals aged 70 to 89 years, we validated the SCORE2-OP models in 5,880 women (205 ASCVD events, 5-year incidence 3.51%, 95% CI: 3.06-4.00) and 4,005 men (223 ASCVD events, 5-year incidence 5.59%, 95% CI: 4.91-6.34). The C-statistic was 0.64 and 0.62 in older women and men, respectively. The uncalibrated models overestimated risk by more than 100% in older women and men. The low-risk region recalibrated model demonstrated improved calibration, but still overestimated risk by 60% in older women and 13% in older men (Figure).

Conclusion: We found a diverging ability of the SCORE2 models to predict ASCVD risk in Canada that differs by age group and whether regional calibration was applied. This supports explicit validation of the SCORE2 models before implementation in new jurisdictions.