External Validation of a Risk Prediction Model for Atherosclerotic Cardiovascular Diseases in a Large National...

The Hisayama risk prediction model for atherosclerotic cardiovascular diseases (ASCVDs) has been featured in the latest Japanese preventive guidelines, yet it lacks external validation.

A retrospective cohort study of 420 552 ASCVD-free individuals aged 40-74 years was performed using data from the national health checkup and administrative claim database recorded between April 2015 and November 2020. Incident cases of ASCVD were ascertained from International Classification of Diseases, Tenth Revision (ICD-10) codes and accompanying medical practice codes.

During a median follow-up of 4.4 years, 3998 individuals developed ASCVD. The Hisayama ASCVD model had good predictive performance in the setting of the Japanese national health checkup. The original model performed well for estimating relative risks (hazard ratio, 32.73 [95% CI, 24.59-43.55] in the highest versus lowest decile) with a satisfactory discriminative ability (Uno's C-statistic, 0.759 [95% CI, 0.751-0.766]), while it tended to overestimate the predicted probability of ASCVD for the study population (calibration-in-the-large, 0.42 [95% CI, 0.41-0.44]). Improved performance was observed after recalibration by substituting the baseline survival rate (calibration-in-the-large, 1.00 [95% CI, 0.97-1.04]) and by refitting the model (calibration-in-the-large, 1.00 [95% CI, 0.97-1.03]; Uno's C-statistic, 0.766 [95% CI, 0.759-0.774]). The predictive performance was good across subgroups of age, sex, and type of insurance.

This external validation study demonstrated that the Hisayama ASCVD model had good predictive performance in the national health checkup setting in Japan, suggesting the use of the Hisayama ASCVD model for efficient risk stratification and risk communication in the nationwide health checkups.