Systematic reviews and meta-analyses in Homeopathy: Recommendations for summarising evidence from homeopathic intervention studies (Sum-HomIS recommendations).

Background: Mainly due to the use of different inclusion criteria and quality assessments, systematic reviews (SRs) and meta-analyses (MAs) with homeopathic intervention studies (HOMIS) have shown inconsistent results. We aimed to build recommendations for "Summarizing evidence from Homeopathic Intervention Studies" (Sum-HomIS recommendations) in order to approach standardization.

Methods: Against the background of a framework-project to update the evidence from homeopathic intervention studies, we launched an expert panel on how to assess the quality of HOMIS and how to summarize evidence from HOMIS. The results of a literature review and the expert communications in advance of the panel as well as the consensus from the discussions are presented here. We added specific considerations for homeopathic veterinary research.

Results: On top of the general guidelines when planning a review we report five basic Sum-HomIS recommendations. These are: 1) A broad literature search including special archives and consideration of so-called grey-literature; 2) The inclusion of controlled observational studies alongside randomized controlled trials; 3) The choice of a clear clinical research question in the terms that, if possible, the review project includes studies with predominantly homogeneous populations, interventions, comparators and outcomes (PICOs); 4) The use of a global quality assessment including the assessment of external, model and internal validity; 5) A summary of evidence using the GRADE-approach if the body of evidence is sufficiently large and homogenous or a descriptive summary if it is not so.

Conclusions: We present recommendations for designing, conducting, and reporting SRs and MAs with HOMIS.