Purpose: To better communicate the impact of poor persistence when preventive therapies are initiated, we propose a new measure that is intuitively understandable for clinicians. This measure is the percent wasted patients (PWP).
Methods: The PWP is the percentage of patients, out of the new users of a given preventive treatment, who have discontinued therapy before the time point at which clinical benefits become apparent on the cumulative incidence curves in randomized controlled trials (RCTs) comparing active treatment to placebo. To calculate the PWP, the RCTs that demonstrated the efficacy of the therapy under study must be identified from a MEDLINE search. The point at which the cumulative incidence curves for the main outcome in the experimental and placebo group start diverging is identified and is called the point of visual divergence (PVD). Then, using pharmaceutical claims databases, the percent persistence at the PVD in new users of the therapy is determined. The PWP is then calculated as 100% persistence at PVD.
Results: For primary prevention with statins, in the province of Quebec, the PWP is 44%. Of 100 patients starting statins for the primary prevention of coronary events, 44 will represent a waste in health resources because they will have discontinued therapy before any clinical benefit can be expected.
Conclusions: The PWP is a simple measure that can be used by clinicians to select the therapies that need the most reinforcement concerning the importance of persistence.
(c) 2005 John Wiley & Sons, Ltd.