Extension of the Composite Quality Score (CQS) as an appraisal tool for prospective, controlled clinical therapy trials (Preprint.v.2)

Aim: to conduct a survey of current meta-epidemiological studies to identify additional trial designcharacteristics that may be associated with significant over/under estimation of the treatment effectand to use such identified characteristics as basis for the formulation of new CQS appraisal criteria.Materials and methods: We retrieved eligible studies from two systematic reviews on this topic(latest search May 2015) and searched the databases PubMed and Embase for further studies fromJune 2015 – March 2022). All data were extracted by one author and verified by another. Sufficientlyhomogeneous estimates from single studies were pooled using random-effects meta-analysis. Trialdesign characteristics associated with statistically significant estimates from single datasets (whichcould not be pooled) and meta-analyses were used as basis to formulate new or to amend existingCQS criteria.Results: A total of 38 meta-epidemiological studies were identified. From these, seven trial designcharacteristics associated with statistically significant over- or under estimation of the truetherapeutic effect were found.Conclusion: One new criterion concerning double blinding was added to the CQS and the originalcriteria for concealing the random allocation sequence and for minimum sample size amended.