BACKGROUND Several systematic reviews (SRs) have investigated the association between ultra -processed foods (UPFs) and the risk of hypertension in various populations. However, the quality of the evidence remains unclear. This umbrella review was thus conducted to fill this gap. METHODS We searched for SRs with and without meta -analyses comparing high UPF versus low UPF consumption on the risk of hypertension in the Cochrane Library, Embase, PubMed, and Web of Science from inception to August 2022. This study was registered in PROSPERO (No. CRD42022352934). The A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR -2) tool and the Preferred Reporting Item for Systematic Review and Meta -analysis 2009 (PRISMA 2009) statement were used to evaluate the methodological and reporting quality of the included SRs. Stata 15/SE was used to reanalyse the data using the random -effects model, and the risk of bias of observational studies from included SRs was reassessed using the Newcastle -Ottawa Scale (NOS) tool. The certainty of the evidence body was assessed using the GRADE recommendation. RESULTS Seven SRs were included in the umbrella review. Among them, nine observational studies (5 cross-sectional and 4 cohort studies), whose available data were resynthesised using meta -analysis. The methodological and reporting quality of the included SRs were relatively poor. The meta -analysis results revealed suggestive evidence of an association between high UPF consumption and the incidence of hypertension (odds ratio: 1.23, 95% con fidence interval: 1.11 to 1.37, p < 0.001, 95% prediction interval: 0.92 to 1.64, critically low certainty) compared to low UPF consumption. CONCLUSION High UPF consumption is associated with an increased risk of hypertension. However, well-conducted SRs, including high -quality prospective cohort studies, are needed to further verify these findings.

Consumption of ultra-processed foods (UPFs) is associated with various adverse health outcomes, which significantly influence the global disease burden. This umbrella review aimed to fill the knowledge gap and guide public health practices by summarizing the association between UPFs and multiple health outcomes. A total of four databases were systematically searched from inception to December 2022, and 14 eligible systematic re-views (SRs) with meta-analyses (MAs) were identified. The SRs were published in 10 journals from 2020 to 2023, with 54,147-5,750,133 participants and 5-61 studies. The overall corrected covered area (CCA) was corresponded to a slight overlap. The results showed that an increased UPFs consumption is associated with multiple health outcomes (e.g., obesity, diabetes, hypertension, mortality). Only two SRs were "Moderate" regarding the overall methodological quality, while the other twelve were "Low" or "Critically low". Therefore, well-conducted SRs with high-quality prospective cohorts with a particular focus on special populations are needed to verify these findings further.

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.

Background: The coronavirus disease 2019 (COVID-19) pandemic continues to grow worldwide, and systematic reviews (SRs)/meta-analyses (MAs) on COVID-19 can efficiently guide evidence-based clinical practice. However, SRs/MAs with weaknesses can mislead clinical practice and pose harm to patients, and too many useless SRs/MAs could pose confusion and waste sources. A "living" overview of SRs/MAs aims to provide an open, accessible and frequently updated resource summarizing the highest-level evidence of COVID-19, that can help evidence-users to quickly identify trusted evidence to guide the practice. This study aims to systematically give an overview SRs/MAs of COVID-19, assess their quality, and identify the best synthesis of evidence. Methods: Databases including Medline, EMBASE, Web of Science, China National Knowledge Infrastructure (CNKI), China Biology Medicine (CBM) and WanFang were systematically searched on May 1, 2020 using relevant terms for identify SRs/MAs related to COVID-19. The study selection, data extraction and quality assessment will be performed by independent reviewers, and results will be crosschecked. The authoritative tools (AMSTAR-2, PRISMA and its extensions) will be used to assess the methodological quality and reporting quality of included SRs/MAs, and potential influence factors will be explored. The consistency of conclusions will be compared among reviews and the best evidence will be summarized. In addition, we will conduct exploratory meta-analyses (MAs) of individual studies when applicable. Data will be reported as number with (or) percentage, risk ratio (RR) or odds ratio (OR), mean difference (MD) or standardized mean difference (SMD) with 95% confidence interval (CI) according to the specific results. R3.6.1 and Microsoft Excel 2016 will be used to analyze and manage data. Results: The results of this overview will be submitted to a peer-reviewed journal for publication. Conclusions: In this study, we will present for the first time, an overview of SRs/MAs, which provides a comprehensive, dynamic evidence landscape on prevalence, prevention, diagnosis, treatment, and prognosis of COVID-19.

Background: Systematic reviews (SRs) with or without meta-analyses (MAs) are widely used in resolving questions in various healthcare areas (such as, traditional Chinese medicine, public health and surgery), and they are the cornerstone of evidence-based healthcare. However, the reliability of SRs is typically influenced by their methodological quality. AMSTAR (A Measurement Tool to Assess Systematic Reviews) and AMSTAR-2 tools can assess the methodological quality of SRs, and the use of AMSTAR has been investigated. However, AMSTAR-2 is now widely used to evaluate the methodological quality of SRs, but the use of AMSTAR-2 for determining the methodological quality of SRs has not yet been investigated and assessed thoroughly. Thus, we designed the present study to investigate the use of AMSTAR-2 in studies that assessed the methodological quality of a sample of SRs with the AMSTAR-2 and provide references to potential users of AMSTAR-2 tool. Methods: Four commonly used electronic databases including PubMed, EmBase, the Cochrane Library, and Web of Science will be searched following a comprehensive search strategy to identify and retrieve studies that have used AMSTAR-2 tool for evaluating the methodological quality of SRs. Two independent authors will retrieve bibliometric information and methodological data, including all author names, time of publication, and journal names, whether a specific score value was given for each item, and whether overall quality assessment was performed. Descriptive statistical analyses will be used to present the study results, e.g., frequencies and percentages, mean and standard deviation (SD) or median and interquartile range (IQR). In addition, subgroup analyses will be performed to identify the methodological differences (e.g., the reporting of study designs included in SRs) between overviews and methodological studies. The risk ratio (RR) with 95% confidence interval (95% CI) will be calculated to measure the methodological differences. Cytoscape 3.7.1 software tool will be used to construct collaboration network maps. Further, Microsoft Office Excel 2016 and Stata 12.0 will be used to manage and analyze data. Discussion: The results of this study will identify any gaps in the use of AMSTAR-2 and important bibliometric features, such as active researchers and journals, provide guidance to researchers in various healthcare areas (such as, traditional Chinese medicine and public health) for using AMSTAR-2 tool and help them in developing cooperation and submitting their manuscripts.