[Methodological issues and suggestions for improvement in randomized controlled trials of Chinese herbal medicine for...

Recurrent miscarriage is a common disease in clinical obstetrics and gynecology. There is no curative treatment for recurrent miscarriage in conventional medicine. Traditional Chinese medicine (TCM) has been widely used in the treatment of recurrent miscarriage in China for thousands of years. However, randomized controlled trials (RCTs) with high quality evaluating the effectiveness and safety of Chinese herbal medicine (CHM) still lack. This study was conducted in order to identify methodological problems in published or unpublished RCTs of CHM in the treatment of recurrent miscarriage, and provide suggestions for TCM researchers to conduct high-quality clinical research.

Literature searching was conducted to collect published and unpublished RCTs from six electronic literature databases, including China National Knowledge Infrastructure, Chongqing VIP Chinese Scientific Journals Database, Chinese Biomedical Literature Database, Wanfang Data, PubMed, and Cochrane Library, till December 15, 2011. The Cochrane Handbook, the CONSORT Statement and the CONSORT for TCM statement were used to assess the methodological quality in the designing and reporting of included trials.

A total of 49 RCTs were included in this critical appraisal. Most of the trials were of high risk of bias with flawed study design and poor methodological quality. The main problems included: no report on random methods or sequence concealment; no calculation of sample size; no flow chart of enrollment and outcomes; no report on blinding methods; no or incomplete report on baseline data such as diagnosis criteria and causes of miscarriage recurrent, age, times of spontaneous abortion, TCM syndrome differentiation; complex CHM treatments and inappropriate control interventions; no report on follow-up and withdrawals; inappropriate outcome measurements such as middle-outcome or laboratory test results; no report on final outcome (live-birth rate).

There are many methodological problems in RCTs of CHM for recurrent miscarriage. It is suggested that four issues should be taken into consideration for TCM research: basic principles of clinical research are needed in design and reporting of RCTs; definite diagnosis criteria and baseline data should be reported in detail; appropriate treatment and control interventions should be selected according to the assumption and objective of research; final outcome (live-birth rate) should be reported in outcome evaluation.