Abstract 15903: “Out-Of Hospital Cardiac Arrest Clinical Trials, Relationship Between Clinical Trial Sample Size and the Odds Ratio of Treatment Effect 1978 to the Present"
Introduction: Randomized clinical trials (RCT) have been conducted in out of hospital cardiac arrest (OOHCA) since at least 1970's. Despite significant effort toward development of clinical trial expertise in resuscitation research, positive trials have been rare. It is well recognized that large treatment effects in early, relatively small clinical trials are often not replicated in later large Phase III trials.
Hypothesis: There is a negative relationship between sample size (SS) and the odds ration (OR) of treatment effect in OOHCA randomized clinical trials (RCT’s).
Methods: Comprehensive online search for RCTs in OOHCA with n > 100 (control group n>50), 1960 to present with extraction of demographic, clinical and outcome variable and regression analysis of SS and OR of treatment effect.
Results: n=72 usable RCTS were identified, all since 1978. There was a significant negative relationship between OR and SS (p < .022) (Figure). No study with a control group larger than than 300 had an OR greater than 1.5.
Limitations: Retrospective methodology and background regional differences limits significance and applicability, hypothesis generating only.
Conclusion: Similar to other clinical entities, OOHCA RCT’s may have a relationship between the OR of treatment effect and the study SS. This effect should be considered in the evaluation and development of new therapies.
- Cardiac arrest
- Cardiopulmonary resuscitation
- Emergency care
- Emergency medical services (EMS)
Author Disclosures: K.M. Engerer: None. J.V. Coleman: None. L.F. Valle: None. M. Roginski: None. N.A. Paradis: None.
- © 2014 by American Heart Association, Inc.