OBJECTIVE: To systematically review current evidence regarding the minimum acceptable risk reduction of a cardiovascular event that patients feel would justify daily intake of a preventive medication.
METHODS: We used the Web of Science to track the forward and backward citations of a set of five key articles until 15 November 2016. Studies were eligible if they quantitatively assessed the minimum acceptable benefit-in absolute values-of a cardiovascular disease preventive medication among a sample of the general population and required participants to choose if they would consider taking the medication.
RESULTS: Of 341 studies screened, we included 22, involving a total of 17 751 participants: 6 studied prolongation of life (POL), 12 studied absolute risk reduction (ARR) and 14 studied number needed to treat (NNT) as measures of risk reduction communicated to the patients. In studies framed using POL, 39%-54% (average: 48%) of participants would consider taking a medication if it prolonged life by <8 months and 56%-73% (average: 64%) if it prolonged life by ≥8 months. In studies framed using ARR, 42%-72% (average: 54%) of participants would consider taking a medication that reduces their 5-year cardiovascular disease (CVD) risk by <3% and 50%-89% (average: 77%) would consider taking a medication that reduces their 5-year CVD risk by ≥3%. In studies framed using 5-year NNT, 31%-81% (average: 60%) of participants would consider taking a medication with an NNT of >30 and 46%-87% (average: 71%) with an NNT of ≤30.
CONCLUSIONS: Many patients require a substantial risk reduction before they consider taking a daily medication worthwhile, even when the medication is described as being side effect free and costless.