Systematic Review of Clinical Trials of Potentized Substances’ Methods and Subgroup Analyses

Background/Aim: Though there exists a considerable amount of randomized controlled trials (RCTs) and several meta-analyses of clinical studies, the effects of homeopathy (HOM) in different indications and application modes remain unclear. The transferability of HOM into experimental conditions of RCTs and vice versa is questioned. We conducted a comprehensive systematic review focusing on both routine practice of potentized substances and applicability of the results for therapeutic use. Therefore, a pathology-based subgroup classification of diseases was developed that addresses the concept of homeopathic interventions interacting with the biophysical regulation systems of the target organism. The study protocol also foresees three meta-analyses: effects of HOM (1) compared with placebo in nine pathology-based subgroups, (2) compared with conventional treatment in nine pathology-based subgroups, and (3) in preventive use.

Method: An extended literature search strategy including “grey literature” was conducted. In contrast to prior reviews, not only RCTs but also controlled observational studies (OS) were eligible. The following indicators were extracted: type of HOM (classical, clinical, complex, isopathy), comparator (conventional treatment, placebo), potency, peer-review, and study design. The classification of studies to pathology-based subgroups was piloted. Risk of bias assessments of internal, external, and homeopathic model validity is ongoing.

Result: Nine pathology-based subgroups have been identified: diseases of traumatic origin, acute inflammatory diseases, chronic inflammatory diseases, chronic degenerative diseases, polygenetic diseases and cancer, functional and multifactorial diseases, psychiatric diseases, pediatric diseases, side-effects of chemotherapy and chronic poisoning. To date, a set of 535 studies have been screened for inclusion and descriptively evaluated. One thousand two hundred and sixteen Masters theses were identified as suitable for further evaluation.

Conclusion: Investigating clinical studies of HOM with meta-analytical means by subgrouping of homeopathic methods, study designs, and pathologies may contribute to a better understanding of the clinical effects of HOM and may open new perspectives for homeopathic research.

Keywords: Systematic review, meta-analysis, research methodology, homeopathic concept