Aims
Clinical guidelines often recommend treating individuals based on their cardiovascular risk. We revisit this paradigm and quantify the efficacy of three treatment strategies: (i) overall prescription, i.e. treatment to all individuals sharing the eligibility criteria of a trial; (ii) risk-stratified prescription, i.e. treatment only to those at an elevated outcome risk; and (iii) prescription based on predicted treatment responsiveness.

Methods and results
We reanalysed the PROSPER randomized controlled trial, which included individuals aged 70–82 years with a history of, or risk factors for, vascular diseases. We conducted the derivation and internal–external validation of a model predicting treatment responsiveness. We compared with placebo (n = 2913): (i) pravastatin (n = 2891); (ii) pravastatin in the presence of previous vascular diseases and placebo in the absence thereof (n = 2925); and (iii) pravastatin in the presence of a favourable prediction of treatment response and placebo in the absence thereof (n = 2890). We found an absolute difference in primary outcome events composed of coronary death, non-fatal myocardial infarction, and fatal or non-fatal stroke, per 10 000 person-years equal to: −78 events (95% CI, −144 to −12) when prescribing pravastatin to all participants; −66 events (95% CI, −114 to −18) when treating only individuals with an elevated vascular risk; and −103 events (95% CI, −162 to −44) when restricting pravastatin to individuals with a favourable prediction of treatment response.

Conclusion
Pravastatin prescription based on predicted responsiveness may have an encouraging potential for cardiovascular prevention. Further external validation of our results and clinical experiments are needed.