Aim: There is no consensus on the optimal time horizon for predicting cardiovascular disease (CVD) risk to inform treatment decisions. New Zealand and Australia recommend 5 years, whereas most countries recommend 10 years. We compared predicted risk and treatment-eligible groups using 5-year and 10-year equations.
Methods: Individual-level linked administrative datasets identified 1,746,665 New Zealanders without CVD, aged 30-74 years in 2006, with follow-up to 2018. Participants were randomly allocated to derivation and validation cohorts. Sex-specific 5-year and 10-year risk prediction models were developed in the derivation cohort and applied in the validation cohort.
Results: 28,116 (3.2%) and 62,027 (7.1%) first CVD events occurred during 5-years and 10-years follow-up respectively (cumulative risk, derivation cohort). Median predicted 10-year CVD risk (3.8%) was approximately 2.5 times 5-year risk (1.6%) and 95% of individuals in the top quintile of 5-year risk were also in the top quintile of 10-year risk, across age/gender groups (validation cohort). Using common guideline-recommended treatment thresholds (5% 5-year, 10% 10-year risk), approximately 14% and 28% of women and men respectively were identified as treatment-eligible applying 5-year equations compared to 17% and 32% of women and men applying 10-year equations. Older age was the major contributor to treatment eligibility in both sexes.
Conclusions: Predicted 10-year CVD risk was approximately 2.5 times 5-year risk. Both equations identified mostly the same individuals in the highest risk quintile. Conversely, commonly used treatment thresholds identified more treatment-eligible individuals using 10-year equations and both equations identified approximately twice as many treatment-eligible men as women. The treatment threshold, rather than the risk horizon, is the main determinant of treatment eligibility.
Keywords: Cardiovascular disease; primary prevention; risk prediction horizon; routine data.
Given the lack of consensus on the optimal time horizon for predicting cardiovascular disease (CVD) risk to inform preventive treatment decisions, our study compared predicted 5-year and 10-year CVD risk in a national cohort of people without prior CVD. 5-year and 10-year CVD risk prediction equations selected largely the same people in the top risk quintile (rank-based comparison), however the overall median 10-year CVD risk was approximately 2.5 times the median 5-year risk. Consequently, common 5-year and 10-year guideline-recommended treatment thresholds (5% 5-year and 10% 10-year risk) identified different proportions of treatment-eligible individuals. Approximately twice as many men as women were identified as treatment-eligible regardless of the risk prediction horizon.These findings indicate that recommended treatment thresholds, not how 5-year and 10-year equations rank individuals by risk, are the main determinant of treatment eligibility.
© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.