Journal Club Summary
Methodology Score: 4/5
Usefulness Score: 3/5
Kudenchuk PJ, et al.
N Engl J Med. 2016 May 5;374(18):1711-22.
This double blind RCT conducted by the ROC enrolled >3000 patients with out of hospital shock refractory cardiac arrest. There was no statistical difference between amiodarone, lidocaine, and placebo in the primary outcome of survival to hospital discharge or secondary outcome of favorable neurological outcome (mRS = or <3). In a pre-specified subgroup analysis, there was an observed difference in treatment effect with respect to whether the out of hospital arrest was witnessed or not, with ARR for amiodarone and lidocaine of 5.0 and 5.2 vs placebo.
By: Dr. Bradley Eason
A meta-analysis may attempt to address a compelling clinical dilemma. But one of the key questions to ask when appraising meta-analyses is whether the pooling of the included studies is appropriate. Clinical diversity (or clinical heterogeneity) reflects differences between study populations, the intervention, co-interventions and/or outcomes when pooling studies in meta-analysis. Methodological diversity (or methodological heterogeneity) is variability in the study designs used and/or risks of biases present. These are distinct from statistical heterogeneity which assesses the variability in the intervention effects being assessed in the included studies. This is a consequence of clinical and/or methodological diversity. Statistical heterogeneity can be determined by: visually assessing the forest plot, measuring the I2 statistic or the Cochran’s Q. A meta-analysis should be done only when the studies are relatively homogeneous for participants, interventions and outcomes to provide a meaningful summary. Always ask yourself if the meta-analysis is combining apples with apples (good) or creating a fruit salad (bad).
By: Dr. Jeff Perry