Model validity of randomised placebo-controlled trials of individualised homeopathic treatment

Purpose : A new programme of systematic reviews of randomised controlled trials (RCTs) of homeopathy distinguishes several key attributes of study design and quality: placebo controlled cf. other-than-placebo controlled; individualised cf. non-individualised homeopathy; treatment cf. prophylaxis; internal validity cf. model validity. The present phase of the review programme focuses on assessing the model validity (MV) of peer-reviewed, placebo-controlled, RCTs of individualised homeopathic treatment.

Methods : A systematic literature search and subsequent reappraisal of retrieved records identified 31 RCTs that satisfied the inclusion criteria for the present study. MV of the eligible RCTs was appraised using a novel criterion-based method. Assessment domains address: (i) the rationale for the choice of the particular homeopathic intervention; (ii) the homeopathic principles reflected in the intervention; (iii) the extent of homeopathic practitioner input; (iv) the relevance of the main outcome measure; (v) the capability of the main outcome measure to detect change; (vi) the length of follow-up to the endpoint of the study. These six MV domains per RCT were categorised by each of three independent assessors as ‘acceptable’, ‘unclear’ or ‘unacceptable’, disparities of opinion being resolved by consensus discussion.

Results : Domain-specific and overall ratings of MV per RCT await the outcome of ongoing consensus discussions. A full set of findings will be presented at conference.

Conclusions : MV data contribute importantly to the appraisal of RCT quality in systematic reviews of homeopathy.