Distribution of cardiovascular disease risk based on the updated 2023 guideline-recommended Australian cardiovascular disease risk algorithm and comparison with the 2012 algorithm

Objective: Australian guidelines on cardiovascular disease (CVD) risk assessment and management, including risk prediction algorithms, were updated in 2023. We quantified CVD risk using the 2023 algorithm, compared this to the previous 2012 algorithm, and considered implications for preventive pharmacotherapy. Design: Comparative analysis. Setting, participants: Data from 115,873 people aged 45-74 years without existing CVD from MedicineInsight, a longitudinal primary-care database covering 8% of Australian general practices. Main outcomes: We applied 2023 and 2012 risk algorithms to estimate and categorise individual-level CVD risk into low, intermediate, and high. Risk re-classification in accordance with the 2023 algorithm was not possible. Cohen's kappa and Bland-Altman plots assessed agreement and concordance. Results: Using the 2023 CVD risk algorithm and revised thresholds, 9.7% of participants were high (≥10% 5-year risk or clinically-determined high risk); 26.4% were intermediate (5-<10% 5-year risk), and 63.9% were low CVD risk (<5% 5-year risk). Corresponding 2012 figures were: 17.6% high (>15% 5-year risk or clinically-determined high risk); 11.6% intermediate (10-15% 5-year risk); and 70.8% low risk (<10% 5-year risk). Differences in proportions at high risk were largely driven by changes to clinically-determined high risk criteria. Overall, there was moderate-to-substantial agreement (kappa=0.62) and concordance (Kendall's tau-b=0.74) between the algorithms. Conclusion: Proportions estimated at low risk and not routinely recommended pharmacotherapy align with international standards and were similar between guidelines. Although fewer people would be recommended pharmacotherapy on the basis of high risk under the updated versus previous guidelines, this reflects better estimates of contemporary risk using the 2023 equation and does not account for re-classification. Pharmacotherapy is considered for those at intermediate risk depending on clinical context under the 2023 guidelines. To ensure continued reduction of the CVD burden across the population, we emphasise the application of re-classification factors and benefits of pharmacotherapy for those at intermediate risk.