Trends in Heart Failure Clinical Trials From 2001–2012

•Trends were examined across 154 HF clinical trials conducted from 2001 to 2012.•HF clinical trials display slow enrollment rates.•Trials meeting their primary end points decreased over time.•Positive trials tended to be smaller in size with a higher proportion of surrogate end points.•Trials conducted exclusively outside North America and Western Europe had the highest enrollment rates.

BackgroundA systematic assessment of the temporal trends in heart failure (HF) clinical trials is lacking.Methods and ResultsA total of 154 phase II–IV HF trials including 162,725 patients published from 2001 to 2012 in 8 high-impact-factor journals were reviewed. The median number of participants and sites per trial were 367 (interquartile range [IQR] 133-1450) and 38 (5–101), respectively. Median enrollment duration was 2.2 (1.5–3.3) years. The majority of studies investigated treatment for chronic HF (82.5%) and investigated HF with reduced ejection fraction (EF) (71.4%), whereas 27 trials (17.5%) enrolled patients with mixed EF and 9 (5.8%) enrolled HF with preserved EF patients alone. Enrollment rates did not significantly change over time (median 0.49 patients site−1 month−1, IQR 0.34–0.98; P = .53). Trials meeting their primary end point decreased over time from 73.5% in 2001–2003 to 52.5% in 2010–2012 (P = .08) and were more often smaller and used nonmortality end points. Industry trials were larger with shorter enrollment duration, more concentrated in North America, and more likely to be positive. Trials conducted exclusively outside North America and Western Europe had the highest enrollment rates (median 1.95 patients site−1 month−1, IQR 1.34–4.11).ConclusionsContemporary HF clinical trials display slow enrollment rates and decreased rates of positive outcomes over time. Positive trials tended to be smaller size with a higher proportion of surrogate end points.