[Outcome indicators in randomized controlled trials on traditional Chinese medicine intervention for tension-type...

To evaluate the application of outcome indicators in randomized controlled trials(RCTs) concerning the treatment of tension-type headache(TTH) with traditional Chinese medicine(TCM) in recent five years, so as to provide a basis for the study of core outcome set(COS) for TCM intervention in TTH. The RCTs on TCM treatment of TTH in recent five years were systematically retrieved from CNKI, Wanfang, VIP, CBM, EMbase, PubMed, Cochrane Library, Web of Science, ClinicalTrials.gov and China Clinical Trial Registry. After literature screening, data extraction and evaluation of the risk of bias, the outcome indicators in the included RCTs were subjected to qualitative analysis. The preliminary search yielded 19 042 articles, and 10 983 were left after the elimination of duplication. Finally, 52 RCTs(48 in Chinese and 4 in English) were included for qualitative analysis. The outcome indicators of RCTs included in this study were classified into seven domains: TCM syndrome, symptom and sign, physical and chemical detection, quality of life, long-term prognosis, economic evaluation, and safety event. The findings demonstrated that headache characteristic index in the symptom and sign domain was the index with the highest reporting frequency and reporting rate. Seventeen RCTs used TCM syndrome score as the outcome indicator. Further analysis revealed that there existed such problems in research design as non-distinction between primary and secondary outcome indicators, great difference in the adopted measurement tools for outcome indicators, and the neglect of measurement time of outcome indicators. Moreover, the syndrome indicators reflecting TCM advantages, objective evaluation indicators, safety and health-economic indicators were lacking. These limitations have affected the quality and reliability of RCTs on TTH treatment with TCM. It is suggested that the efficacy and characteristics of TCM should be combined into current clinical research, and the COS in RCTs regarding TCM treatment of TTH should be established according to internationally recognized standard procedures.