Background: Many meta-analyses (MAs) on Chinese medicine (CM) as an adjunctive treatment for gastric cancer have been published in recent years. However, the pooled evidence reported in MAs and their methodological quality remain unknown. Therefore, we designed a study to comprehensively evaluate and summarize the current evidence of CMs for gastric cancer in published MAs. Methods: A systematic search on MAs published in English from inception to 1st September 2021 was conducted in PubMed and Embase. The AMSTAR-2 tool was used to evaluate the methodological quality of the included MAs, and the results of the quality assessment were visualized using the evidence mapping method. Stata 17/SE was used for statistical analysis (Registration number: INPLASY202190005). Results: A total of 20 MAs (16 pairwise and 4 network MAs) were included from 118 records. These MAs were published in 14 journals from 2013 to 2021, with the number of patients and trials ranging from 688 to 6,857, and from 10 to 85, respectively. A large number of CMs (e.g., AiDi, FuFangKuShen, and HuaChanSu) in combination with chemotherapy for gastric cancer were identified among the included MAs. According to the pooled results reported in MAs, when compared to chemotherapy alone, CMs in combination with chemotherapy not only improve various outcomes on efficacy (e.g., objective response rate, quality of life) but also reduce various adverse reactions (e.g., leucopenia, nausea and vomiting). Only 2 MAs were low in terms of the overall methodological quality, while the other 18 MAs were all critically low. The methodology was required to be advanced significantly, mainly involving: study protocol and registration, explanation for the inclusion of study design, list of excluded studies with justifications, adequate details of included studies, reporting on funding sources of primary studies, and evaluation of the potential impact of risk of bias. In addition, MAs that received funds support (β = 2.68; 95%CI: 0.40 to 4.96; p = 0.024) or were published in journals with higher impact factor (β = 2.81; 95%CI: 0.69 to 4.92; p = 0.012) had a higher score on the overall methodological quality in the univariate analysis, but the results were not statistically significant according to the multivariate analysis. Conclusion: Combining CMs with chemotherapy can potentially improve clinical outcomes and reduce the relevant adverse effects in patients with gastric cancer. However, the methodological quality of relevant MAs requires significant improvement, and the current evidence needs to be validated through multinational trials that are well-designed and have a large sample size.

Background: Although a number of systematic reviews and meta-analyses of saffron (Crocus sativus L.) have been published, no study has comprehensively summarized the clinical evidence from meta-analyses, or assessed the reporting or methodological quality of these reviews. Purpose: The present meta-research study was designed to fill the gaps in knowledge to inform future studies and allow enhanced clinical decision-making on saffron. Methods: The PubMed, Cochrane Library, Embase, and CNKI databases were systematically searched from inception to April 3 rd, 2021, for meta-analyses of clinical trials that assessed the efficacy and safety of saffron. PRISMA 2009 and AMSTAR-2 were employed to assess the reporting and methodological quality of meta-analyses identified in the search, respectively. The present study was registered on PROSPERO with registration number CRD42020220274. Results: Nineteen eligible systematic reviews with meta-analyses published in English were identified from 235 records. These meta-analyses were published in 12 peer-reviewed journals from 2013 to 2021. The heterogeneous results indicated that saffron significantly reduced fasting blood glucose, waist circumference, diastolic blood pressure, concentrations of total cholesterol and low-density lipoprotein cholesterol, and improved symptoms of depression, cognitive function and sexual dysfunction compared with controls (mainly placebos). Common side effects of saffron consumption included nausea, dry mouth, poor appetite, and headache, but no serious adverse reactions were reported. Primary analysis and sensitivity analysis confirmed that the reporting and methodological quality of reviews included in the study were highly correlated (p < 0.001). The quality of meta-analyses of saffron requires improvement by including a structured abstract, a prospective protocol and registration, explanation of the study designs within each study that is reviewed, the searches, risk of bias assessment, literature selection, and reporting of funding sources. Conclusion: The available evidence indicates that saffron is a safe plant for administration as a medicine and can improve diverse clinical outcomes, but the scientific quality of the published systematic reviews needs to be improved. Moreover, the clinical effects of saffron need to be confirmed through high-quality randomized trials in multiple countries with large sample sizes.