65: Mixing the medians and means in meta-analyses

Music City Center 

The definition of " Evidence-based medicine (EBM) is the conscientious, explicit, judicious and reasonable use of modern, best evidence in making decisions about the care of individual patients. (Sackett et al 1996)" Meta-analysis is an important tool of EBM and a method for obtaining the best evidence. Typically, meta-analysis methods rely on the assumption of normal distribution. Therefore, the mean, standard deviation (sd), and sample size are extracted from each study. However, some studies only provide the median, interquartile range (IQR), maximum, and minimum. In these cases, formulae can be used to convert this information into mean and sd, and the meta-analysis can then proceed. To evaluate the feasibility and robustness of this approach, we use a simulation method to obtain mean and sd for different proportions of studies reporting the medians and IQR and for different numbers of studies in a meta-analysis. This knowledge is essential for meta-analysts, providing them with a rule to follow when conducting these types of analyses and enabling them to provide the best evidence for EBM.

Evidence-based medicine

meta-analyses

median

mean 

Health Policy Statistics Section