Quality of randomized controlled trials of new generation antidepressants and antipsychotics identified in the China National Knowledge Infrastructure (CNKI): a literature and telephone interview study

BACKGROUND: We are witnessing an exponential increase in the number of randomized controlled trials (RCTs) reported from mainland China. The increase is particularly notable in the field of new generation antidepressants and antipsychotics. Several previous studies have raised doubts regarding their quality. However, the quality of most recent RCTs published in China may have improved. METHODS: We searched RCTs that examined new generation antidepressants and antipsychotics published between 2013 and 2016 in the China National Knowledge Infrastructure (CNKI), the largest database of scientific publications in China. We interviewed the authors of a random subset of the identified references. We assessed the methodological rigor of each study based on the published reports and telephone interviews with the authors using six methodological domains adapted from the Cochrane’s risk of bias tool. RESULTS: The final sample consisted of 138 studies, for which we interviewed 58 authors; the authors of 51 studies declined the interview, and the authors of 29 studies could not be contacted. The 51 studies with refused interviews were significantly less likely to be reported from university-affiliated hospitals and were less likely to be published in Chinese core journals. Based on the published reports, most of the 58 studies were assessed to be at unclear risk of bias in most methodological domains. After the interview, only 10 studies were assessed to be at low risk of bias for sequence generation and allocation concealment. Assuming that the studies for which the authors declined interviews had an unclear risk, the proportion of RCTs at low risk of bias in both sequence generation and allocation concealment was 9.2% (10/109, 95% confidence interval [CI]: 5.0 to 16.2). The interviews indicated that the studies were at high risk of bias for most of the other domains. CONCLUSION: In general, RCTs that evaluate new generation antidepressants or antipsychotics and are indexed in the CNKI continue to be of low quality. When conducting systematic reviews and meta-analyses in this field, it would be wise to include a specialist from China as a coresearcher to help assess the risk of bias in the identified studies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12874-018-0554-2) contains supplementary material, which is available to authorized users.