Objective      As a severe public health problem

male infertility has always been the point at issue on how to diagnose and treat effectively. Traditional Chinese medicines have been used to treat male infertility with a long history and rich experiences

however

their effects have not yet been evaluated rigorously up to now. This paper aims to systematically evaluate the risks of bias of non-randomized studies(NRS) of traditional Chinese medicines in the management of male infertility

so as to provide invaluable information for further clinical and scientific references.       Methods      We searched the data about male infertility and traditional Chinese medicines from the Cochrane central register of controlled trials (CCRCT)

PubMed

Embase and Chinese biomedical literature database (Sinomed)until February 30

2013. Literature search strategies took the form of combination of subject headings and freewords such as “traditional Chinese medicine”

“Chinese medicine”

“complementary therapies” and “male infertility” as search words. Only NRS of traditional Chinese medicine therapies for male infertility were included. Two reviewers (Xiong

Li) independently screened the studies for eligibility and evaluated the risks of bias of the included studies based on Cochrane risk of bias assessment tool for non-randomized studies of interventions (ACROBAT-NRSI)

and meanwhile

the discussion on related problems were conducted.       Results       Fifty-three NRS (8 studies from CCRCT

4 studies from PubMed

and 41 studies from Sinomed)

which were published in Chinese and English and involved 7 159 men (average 135 patients per study) with infertility

were included in the research. The diagnosis of the included studies mainly included oligospermia

asthenozoospermia and immunological infertility. The control interventions included Western medicine therapies in 29 studies (54.72%)

surgery in 3 studies (5.66%)

blank control in 1 study and traditional Chinese medicine therapies in 20 studies (37.74%). The risks of bias for all the 53 studies were serious

and especially

the risks of bias of 20 studies were critical (37.74%).The bias risk domains of single study showed higher proportions

and the serious and critical risks of bias due to confounding were 73.58% and 16.98%

respectively. The moderate risk of bias in selection of participants into the study was 86.8%

and the low and moderate risks of bias in measurement of interventions were 67.92% and 30.19%

respectively. The low and serious risks of bias due to departures from intended interventions were 88.68% and 11.32%

respectively. The low risk of bias due to missing data was 86.79%

and serious risk of bias in measurement of outcomes was 100%. The serious and moderate risks of bias in selection of the reported result were 83.02% and 11.32%

respectively.The serious and critical risks of bias in the overall judgment about risk of bias were 63.26% and 37.74%

respectively. The low

moderate

serious and critical risks of bias for all 512 studies were 35.58%

19.41%

12.94% and 4.85%

respectively.  ……       Conclusion       ACROBAT-NRSI is suitable for evaluating the bias risks of NRS of traditional Chinese medicines for male infertility

but there are some limitations of inherent characteristics of traditional Chinese medicines

and the bias risks are serious. It is advised to improve and optimize the ACROBAT-NRSI in the bias domains of selection of participants into the study

measurement of interventions and measurement of outcomes. Moreover

the experts with subject-matter knowledge of traditional Chinese medicines should be included into the appraisal process.