Comment on: Efficacy and safety of tigecycline: a systematic review and meta-analysis

published a systematic review andmeta-analysis of 15 randomized clinical trials (RCTs) that com-pared tigecycline with other antibiotics for the treatment ofsevere infections. The overall 30 day mortality was estimatedto be higher with tigecycline compared with other regimens[relative risk (RR) 1.29, 95% condence interval (CI) 1.02–1.64];therefore, the authors recommend that clinicians should avoidtigecycline monotherapy in the treatment of severe infectionsand reserve it as a last-resort drug.The authors performed a test of heterogeneity betweenstudies. Given that the test result was not signicant at 5%, theydecided to pool all the RRs by using a xed-effect meta-analysismodel.Unfortunately,thisisacommonpracticeinmeta-analysis,which usually leads to very misleading results. First of all, thepooled RR as well as its standard error are sensitive to theestimation of the between-studies standard deviation (SD).