Risk stratification and treatment effect of statins in secondary cardiovascular prevention in old age: Additive value of N-terminal pro-B-type natriuretic peptide.

Background To date, no validated risk scores exist for prediction of recurrence risk or potential treatment effect for older people with a history of a cardiovascular event. Therefore, we assessed predictive values for recurrent cardiovascular disease of models with age and sex, traditional cardiovascular risk markers, and SMART risk score', all with and without addition of N-terminal pro-B-type natriuretic peptide (NT-proBNP). Treatment effect of pravastatin was assessed across low and high risk groups identified by the best performing models. Design and methods Post-hoc analysis in 2348 participants (age 70-82 years) with a history of cardiovascular disease within the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) study. Composite endpoint was a recurrent cardiovascular event/cardiovascular mortality. Results The models with age and sex, traditional risk markers and SMART risk score had comparable predictive values (area under the curve (AUC) 0.58, 0.61 and 0.59, respectively). Addition of NT-proBNP to these models improved AUCs with 0.07 (p for difference ((p(diff)))=0.003), 0.05 (p(diff)=0.009) and 0.06 (p(diff)<0.001), respectively. For the model with age, sex and NT-proBNP, the hazard ratio for the composite endpoint in pravastatin users compared with placebo was 0.67 (95% confidence interval 0.49-0.90) for those in the highest third of predicted risk and 0.91 (0.57-1.46) in the lowest third, number needed to treat 12 and 115 (p(diff)=0.038) respectively. Conclusion In secondary cardiovascular prevention in old age addition of NT-proBNP improves prediction of recurrent cardiovascular disease, cardiovascular mortality and treatment effect of pravastatin. A minimal model including age, sex and NT-proBNP predicts as accurately as complex risk models including NT-proBNP.