  In this work, we introduce a personalised and age-specific Net Benefit
function, composed of benefits and costs, to recommend optimal timing of risk
assessments for cardiovascular disease prevention. We extend the 2-stage
landmarking model to estimate patient-specific CVD risk profiles, adjusting for
time-varying covariates. We apply our model to data from the Clinical Practice
Research Datalink, comprising primary care electronic health records from the
UK. We find that people at lower risk could be recommended an optimal
risk-assessment interval of 5 years or more. Time-varying risk-factors are
required to discriminate between more frequent schedules for higher-risk
people.
