Background The massive abundance of studies relating to tropical medicine and health has increased strikingly over the last few decades. In the field of tropical medicine and health, a well-conducted systematic review and meta-analysis (SR/MA) is considered a feasible solution for keeping clinicians abreast of current evidence-based medicine. Understanding of SR/MA steps is of paramount importance for its conduction. It is not easy to be done as there are obstacles that could face the researcher. To solve those hindrances, this methodology study aimed to provide a step-by-step approach mainly for beginners and junior researchers, in the field of tropical medicine and other health care fields, on how to properly conduct a SR/MA, in which all the steps here depicts our experience and expertise combined with the already well-known and accepted international guidance. We suggest that all steps of SR/MA should be done independently by 2–3 reviewers’ discussion, to ensure data quality and accuracy. Conclusion SR/MA steps include the development of research question, forming criteria, search strategy, searching databases, protocol registration, title, abstract, full-text screening, manual searching, extracting data, quality assessment, data checking, statistical analysis, double data checking, and manuscript writing. Electronic supplementary material The online version of this article (10.1186/s41182-019-0165-6) contains supplementary material, which is available to authorized users.

Leukemia is the most commonly diagnosed childhood cancer, although its etiology is still largely unknown. Growing evidence supports a role for infection in the etiology of acute lymphocytic leukemia (ALL), and the involvement of the immune system suggests that vaccination may also play a role. However, the findings presented in the published literature are inconsistent. Therefore, we conducted a PRISMA systematic review and meta-analysis. 14 studies were identified and meta-analyzed. Vaccinations studied comprised Bacillus Calmette-Guérin (BCG) vaccine, Triple vaccine, Hepatitis B vaccine (HBV), Polio, Measles, Rubella, Mumps, trivalent MMR vaccine and Haemophilus influenza type B (HiB) vaccine. We observed a protective association between any vaccination in the first year of life and risk of childhood leukemia (summary odds ratio (OR) 0.58 [95% confidence interval (CI) 0.36–0.91]). When individual vaccines were analysed, some evidence of an association was seen only for BCG (summary OR 0.73 [95% CI 0.50–1.08]). In conclusion, early vaccination appears to be associated with a reduced risk of childhood leukemia. This finding may be underpinned by the association observed for BCG. Given the relatively imprecise nature of the results of this meta-analysis, our findings should be interpreted cautiously and replicated in future studies.

Systematic reviews and/or meta-analyses generally provide the best evidence for medical research. Authors are recommended to use flow diagrams to present the review process, allowing for better understanding among readers. However, no studies as of yet have assessed the quality of flow diagrams in systematic review/meta-analyses. Our study aims to evaluate the quality of systematic review/meta-analyses over a period of ten years, by assessing the quality of the flow diagrams, and the correlation to the methodological quality. Two hundred articles of “systematic review” and/or “meta-analysis” from January 2004 to August 2015 were randomly retrieved in Pubmed to be assessed for the flow diagram and methodological qualities. The flow diagrams were evaluated using a 16-grade scale corresponding to the four stages of PRISMA flow diagram. It composes four parts: Identification, Screening, Eligibility and Inclusion. Of the 200 articles screened, 154 articles were included and were assessed with AMSTAR checklist. Among them, 78 articles (50.6%) had the flow diagram. Over ten years, the proportion of papers with flow diagram available had been increasing significantly with regression coefficient beta = 5.649 (p = 0.002). However, the improvement in quality of the flow diagram increased slightly but not significantly (regression coefficient beta = 0.177, p = 0.133). Our analysis showed high variation in the proportion of articles that reported flow diagram components. The lowest proportions were 1% for reporting methods of duplicates removal in screening phase, followed by 6% for manual search in identification phase, 22% for number of studies for each specific/subgroup analysis, 27% for number of articles retrieved from each database, and 31% for number of studies included in qualitative analysis. The flow diagram quality was correlated with the methodological quality with the Pearson’s coefficient r = 0.32 (p = 0.0039). Therefore, this review suggests that the reporting quality of flow diagram is less satisfactory, hence not maximizing the potential benefit of the flow diagrams. A guideline with standardized flow diagram is recommended to improve the quality of systematic reviews, and to enable better reader comprehension of the review process.

Summary SARS Coronavirus‐2 is one of the most widespread viruses globally during the 21st century, whose severity and ability to cause severe pneumonia and death vary. We performed a comprehensive systematic review of all studies that met our standardised criteria and then extracted data on the age, symptoms, and different treatments of Covid‐19 patients and the prognosis of this disease during follow‐up. Cases in this study were divided according to severity and death status and meta‐analysed separately using raw mean and single proportion methods. We included 171 complete studies including 62,909 confirmed cases of Covid‐19, of which 148 studies were meta‐analysed. Symptoms clearly emerged in an escalating manner from mild‐moderate symptoms, pneumonia, severe‐critical to the group of non‐survivors. Hypertension (Pooled proportion (PP): 0.48 [95% Confident interval (CI): 0.35–0.61]), diabetes (PP: 0.23 [95% CI: 0.16–0.33]) and smoking (PP: 0.12 [95% CI: 0.03–0.38]) were highest regarding pre‐infection comorbidities in the non‐survivor group. While acute respiratory distress syndrome (PP: 0.49 [95% CI: 0.29–0.78]), (PP: 0.63 [95% CI: 0.34–0.97]) remained one of the most common complications in the severe and death group respectively. Bilateral ground‐glass opacification (PP: 0.68 [95% CI: 0.59–0.75]) was the most visible radiological image. The mortality rates estimated (PP: 0.11 [95% CI: 0.06–0.19]), (PP: 0.03 [95% CI: 0.01–0.05]), and (PP: 0.01 [95% CI: 0–0.3]) in severe‐critical, pneumonia and mild‐moderate groups respectively. This study can serve as a high evidence guideline for different clinical presentations of Covid‐19, graded from mild to severe, and for special forms like pneumonia and death groups.

Aim: Diuretics are a cornerstone in treatment of heart failure (HF). Torasemide is a loop diuretic with a potential advantage over other diuretics. We aim to meta-analyse and compare the effect of torasemide with furosemide in HF patients.Methods: A comprehensive literature search using 12 databases including PubMed, Scopus, and Web of Science was performed. All randomized controlled trials (RCTs) comparing furosemide and torasemide in HF patients were included and metaanalysed. We assessed the risk of bias using Cochrane Collaboration's tool. The protocol was registered in PROSPERO (CRD42016046112).