ObjectivesThis study sought to determine the degree to which U.S. patients enrolled in a heart failure (HF) trial represent patients in routine U.S. clinical practice according to race and sex.BackgroundBlack patients and women are frequently under-represented in HF clinical trials. However, the degree to which black patients and women enrolled in trials represent such patients in routine practice is unclear.MethodsThe ASCEND-HF (Acute Study of Clinical Effectiveness of Nesiritide in Decompensated HeartFailure) trial randomized patients hospitalized for HF to receive nesiritide or placebo from May 2007 to August 2010 and was neutral for clinical endpoints. This analysis compared non-Hispanic white (n=1,494) and black (n=1,012) patients enrolled in ASCEND-HF from the U.S. versus non-Hispanic white and black patients included in a U.S. hospitalized HF registry (i.e.,Get With The Guidelines-Heart Failure [GWTG-HF]) during the ASCEND-HF enrollment period and meeting trial eligibility criteria.ResultsAmong 79,291 white and black registry patients, 49,063 (62%) met trial eligibility criteria (white, n=37,883 [77.2%]; black, n=11,180 [22.8%]). Women represented 35% and 49% of the ASCEND-HF and trial-eligible GWTG-HF cohorts, respectively. Compared with trial-enrolled patients, trial-eligible GWTG-HF patients tended to be older with higher blood pressure and higher ejection fraction. Trial-eligible patients had higher in-hospital mortality (2.3% vs. 1.3%), 30-day readmission (20.2% vs. 16.8%), and 180-day mortality (21.2% vs. 18.6%) than those enrolled in the trial (all p