Randomised controlled trials of veterinary homeopathy: characterising the peer-reviewed research literature for systematic review.

INTRODUCTION Systematic review of the research evidence in veterinary homeopathy has never previously been carried out. This paper presents the search methods, together with categorised lists of retrieved records, that enable us to identify the literature that is acceptable for future systematic review of randomised controlled trials (RCTs) in veterinary homeopathy. METHODS All randomised and controlled trials of homeopathic intervention (prophylaxis and/or treatment of disease, in any species except man) were appraised according to pre-specified criteria. The following databases were systematically searched from their inception up to and including March 2011: AMED; Carstens-Stiftung Homeopathic Veterinary Clinical Research (HomVetCR) database; CINAHL; Cochrane Central Register of Controlled Trials; Embase; Hom-Inform; LILACS; PubMed; Science Citation Index; Scopus. RESULTS One hundred and fifty records were retrieved; 38 satisfied the acceptance criteria (substantive report of a clinical treatment or prophylaxis trial in veterinary homeopathic medicine randomised and controlled and published in a peer-reviewed journal), and were thus eligible for future planned systematic review. Approximately half of the rejected records were theses. Seven species and 27 different species-specific medical conditions were represented in the 38 papers. Similar numbers of papers reported trials of treatment and prophylaxis (n=21 and n=17 respectively) and were controlled against placebo or other than placebo (n=18, n=20 respectively). Most research focused on non-individualised homeopathy (n=35 papers) compared with individualised homeopathy (n=3). CONCLUSION The results provide a complete and clarified view of the RCT literature in veterinary homeopathy. We will systematically review the 38 substantive peer-reviewed journal articles under the main headings: treatment trials; prophylaxis trials.