Patient Eligibility for Randomized Controlled Trials in Critical Care Medicine: An International Two-Center Observational Study

Objective: We conducted this study to determine the generalizability of information gained from randomized controlled trials in critically ill patients by assessing the incidence of eligibility for each trial.

Design: Prospective, observational cohort study. We identified the 15 most highly cited randomized controlled trials in critical care medicine published between 1998 and 2008. We examined the inclusion and exclusion criteria for each randomized controlled trial and then assessed the eligibility of each patient admitted to a study ICU for each randomized controlled trial and calculated rates of potential trial eligibility in the cohort.

Setting: Three ICUs in two academic medical centers in Canada and the United States.

Patients: Adults admitted to participating medical or surgical ICU in November 2010 or July 2011.

Measurements And Main Results: Among the 15 trials, the most common trial inclusion criteria were clinical criteria for sepsis (six trials) or acute respiratory distress syndrome (four trials), use of invasive mechanical ventilation (five trials) or related to ICU type or duration of ICU stay (five trials). Of the 93 patients admitted to a study ICU, 52% of patients (n = 48) did not meet enrollment criteria for any studied randomized controlled trial and 30% (n = 28) were eligible for only one of the 15. Trial ineligibility was mostly due to failure to meet inclusion criteria (87% of screening assessments) rather than meeting specific exclusion criteria (52% of screening assessments). Of the positive screening assessments, 85% occurred on the first day of ICU admission.

Conclusions: Slightly more than half of the patients assessed were not eligible for enrollment in any of 15 major randomized controlled trials in critical care, most often due to the absence of the specific clinical condition of study. The majority of patients who met criteria for a randomized controlled trial did so on the first day of ICU admission.