Background
Cardiovascular disease (CVD) risk models are primarily used in clinical settings to inform individual risk management decisions. We sought to develop and validate alternative equations derived solely from linked routinely-collected national health data, that could be applied country-wide to inform population health planning.
Methods
Individual-level linkage of eight administrative health datasets identified all New Zealand residents aged 30-74 years in contact with publicly-funded health services during 2006 with no previous CVD or heart failure hospitalisations, and with complete data on eight pre-specified predictors. Sex-specific Cox models were developed to estimate risk of CVD death or hospitalisation within five years and included sex, age, ethnicity, level of deprivation, diabetes, previous hospitalisation for atrial fibrillation, and baseline preventive pharmacotherapy as predictors. Calibration and discrimination were assessed in the whole cohort and in 15-year age bands, different ethnic groups, quintiles of deprivation, regional sub-populations and according to baseline dispensing of pharmacotherapy.
Results
First CVD events occurred in 62,031 of the 1,746,695 people during 8,526,024 person-years of follow-up (mean=4.8 years). Median five-year CVD risk was 1.1% in women and 2.6% in men. In both sexes, the risk equations were well calibrated throughout the risk range and had good risk discrimination in the national, regional and ethnic populations, within 15-year age bands, in deprivation quintiles and according to baseline medication dispensing.
Conclusions
Robust policy-focussed CVD risk equations can be developed solely from administrative health data to inform population health planning, and will complement CVD primary prevention at the individual level using clinical risk tools.