Outcomes and statistical power in adult critical care randomized trials.

Intensive care unit (ICU)-based randomized clinical trials (RCTs) among adult critically ill patients commonly fail to detect treatment benefits.
Appraise the rates of success, outcomes used, statistical power, and design characteristics of published trials.
One hundred forty-six ICU-based RCTs of diagnostic, therapeutic, or process/systems interventions published from January 2007 to May 2013 in 16 high-impact general or critical care journals were studied.
Of 146 RCTs, 54 (37%) were positive (i.e., the a priori hypothesis was found to be statistically significant). The most common primary outcomes were mortality (n = 40 trials), infection-related outcomes (n = 33), and ventilation-related outcomes (n = 30), with positive results found in 10, 58, and 43%, respectively. Statistical power was discussed in 135 RCTs (92%); 92 cited a rationale for their power parameters. Twenty trials failed to achieve at least 95% of their reported target sample size, including 11 that were stopped early due to insufficient accrual/logistical issues. Of 34 superiority RCTs comparing mortality between treatment arms, 13 (38%) accrued a sample size large enough to find an absolute mortality reduction of 10% or less. In 22 of these trials the observed control-arm mortality rate differed from the predicted rate by at least 7.5%.
ICU-based RCTs are commonly negative and powered to identify what appear to be unrealistic treatment effects, particularly when using mortality as the primary outcome. Additional concerns include a lack of standardized methods for assessing common outcomes, unclear justifications for statistical power calculations, insufficient patient accrual, and incorrect predictions of baseline event rates.
AuthorsMichael O Harhay, Jason Wagner, Sarah J Ratcliffe, Rachel S Bronheim, Anand Gopal, Sydney Green, Elizabeth Cooney, Mark E Mikkelsen, Meeta Prasad Kerlin, Dylan S Small, Scott D Halpern
JournalAmerican journal of respiratory and critical care medicine (Am J Respir Crit Care Med) Vol. 189 Issue 12 Pg. 1469-78 (Jun 15 2014) ISSN: 1535-4970 [Electronic] United States
PMID24786714 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, N.I.H., Intramural)
  • Adult
  • Critical Care
  • Data Interpretation, Statistical
  • Humans
  • Intensive Care Units
  • Logistic Models
  • Odds Ratio
  • Outcome Assessment (Health Care) (methods, statistics & numerical data)
  • Poisson Distribution
  • Randomized Controlled Trials as Topic (methods, statistics & numerical data)
  • Research Design (statistics & numerical data)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research network!

Choose Username:
Verify Password: