Issues of design and statistical analysis in controlled clinical acupuncture trials: an analysis of English-language reports from Western journals.

OBJECTIVE: To investigate major methods of design and statistical analysis in controlled clinical acupuncture trials published in the West during the past six years (2003-2009) and, based on this analysis, to provide recommendations that address methodological issues and challenges in clinical acupuncture research.
METHOD: PubMed was searched for acupuncture RCTs published in Western journals in English between 2003 and 2009. The keyword used was acupuncture.
RESULTS: One hundred and eight qualified reports of acupuncture trials that included more than 30 symptoms/conditions were identified, analyzed, and grouped into efficacy (explanatory), effectiveness (pragmatically beneficial), and other (unspecified) studies. All were randomized controlled clinical trials (RCTs). In spite of significant improvement in the quality of acupuncture RCTs in the last 30 years, these reports show that some methodological issues and shortcomings in design and analysis remain. Moreover, the quality of the efficacy studies was not superior to that of the other types of studies. Research design and reporting problems include unclear patient criteria and inadequate practitioner eligibility, inadequate randomization, and blinding, deficiencies in the selection of controls, and improper outcome measurements. The problems in statistical analysis included insufficient sample sizes and power calculations, inadequate handling of missing data and multiple comparisons, and inefficient methods for dealing with repeated measure and cluster data, baseline value adjustment, and confounding issues.
CONCLUSION: Despite recent advancements in acupuncture research, acupuncture RCTs can be improved, and more rigorous research methods should be carefully considered.