Age-, sex-, and race-based differences among patients enrolled versus not enrolled in acute lung injury clinical trials

Objective: Little is known about the participation of racial/ethnic minorities, women, and the elderly into critical care clinical trials. We sought to characterize the representation of racial and ethnic minorities, women, and older patients in clinical trials of patients with acute lung injury and to determine the reasons for nonenrollment. Design, Setting, and Patients: We performed a cross-sectional analysis of pooled screening logs from 44 academic hospitals participating in three multicentered, randomized, controlled trials conducted by the Acute Respiratory Distress Syndrome Network from 1996 to 2005. Interventions: None. Measurements and Main Results: We calculated odds ratios of enrollment for age, sex, racial groups, and the odds ratio for the presence of each exclusion criterion by age, sex, and race adjusted for demographics, acute lung injury risk factor, study, and study center. A total of 10.4% of 17,459 screened patients with acute lung injury were enrolled. The median (range) enrollment by center was 15% (2% to 88%). Older patients of both sexes were less likely to be enrolled, but older women were more likely to be enrolled than older men. The adjusted odds ratio (95% confidence interval) for enrollment among men >= 75 yrs of age was 0.59 (0.45 to 0.77) and for women >= 75 yrs of age was 0.45 (0.32 to 0.62) compared with men < 35 yrs of age. There were no differences in the likelihood of enrollment among all racial/ethnic groups. Older patients and men were less likely to be enrolled because of medical comorbidity. Among all patients who were not enrolled, black patients and their families refused participation more often than white patients. Conclusions: Older patients are less likely to be enrolled in acute lung injury clinical trials. There is no evidence that women or racial/ethnic minorities are underrepresented in acute lung injury clinical trials. (Crit Care Med 2010; 38: 1450-1457)