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Impact of Study Quality on Outcome in Placebo-Controlled Trials of Homeopathy

Impact of Study Quality on Outcome in Placebo-Controlled Trials of Homeopathy,10.1016/S0895-4356(99)00048-7,Journal of Clinical Epidemiology,Klaus Lin

Impact of Study Quality on Outcome in Placebo-Controlled Trials of Homeopathy   (Citations: 66)
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We investigated the influence of indicators of methodological quality on study outcome in a set of 89 placebo-controlled clinical trials of homoeopathy in three different ways: (1) The results of studies meeting single criteria (explicit statement of random allocation, allocation concealment, double-blinding, completeness of follow-up) of methodological quality were compared with those of studies not meeting the criteria in univariate and multivariate analyses; (2) The results of studies scoring above and below predefined scores in two quality assessment scales were compared; (3) Primary studies were consecutively entered into a cumulative meta-analysis according to the summary scores derived from the quality assessment scales. All analyses were performed using meta-regression methods. Studies that were explicitly randomized and were double-blind as well as studies scoring above the cut-points yielded significantly less positive results than studies not meeting the criteria. In the cumulative meta-analyses, there was a trend for increasing effect sizes when more studies with lower-quality scores were added. However, there was no linear relationship between quality scores and study outcome. We conclude that in the study set investigated, there was clear evidence that studies with better methodological quality tended to yield less positive results. Because summarizing disparate study features into a single score is problematic, meta-regression methods simultaneously investigating the influence of single study features seem the best method for investigating the impact of study quality on outcome.
Journal: Journal of Clinical Epidemiology - J CLIN EPIDEMIOL , vol. 52, no. 7, pp. 631-636, 1999
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    • ...It is not just the quality of the systematic reviews that makes analysis of CAM data complex, the quality of the RCTs included plays an even greater role. Studies assessing the RCTs of homeopathy have suggested that RCTs of better methodological quality tend to yield less positive results than RCTs of high quality....

    Katherine Huntet al. The evidence-base for complementary medicine in children: a critical o...

    • ... As it turns out, systematic reviews of the research show that the more positive results are from methodogically weaker studies, while stronger methodology tends inexorably toward the conclusion of placebo plus experimenter bias...

    G. Chapman. A substantial gap

    • ... This is one of four meta analyses in high impact factor journals to reach the same conclusion, the others being published in The Lancet, British Medical Journal, and European Journal of Clinical Pharmacology...

    G. Chapman. Proto-medicine

    • ...contains perhaps the most positive assessment of homeopathy ever published in mainstream literature. However, less often cited is the subsequent paper from the same authors which reanalysed their original data and came to much less encouraging conclusions (...

    Morag G. Kerret al. Pilot study of the effect of homeopathy on pruritus associated with at...

    • ...Both analyses showed that the trial results depended on a number of external parameters, such as the methodological quality of the trial, the publication language, the type of publication, and the precision of the effect estimator, hereby confirming previous results on randomized clinical trials in homeopathy [2]...

    R. Lüdtkeet al. The conclusions on the effectiveness of homeopathy highly depend on th...

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