How to interpret a meta-analysis?

There is an enormous and ever-growing quantity of healthcare information available and practitioners must transform it into knowledge to be able to use it in their clinical practice. Even readers who do not conduct scientific studies themselves need to understand the scientific method in detail to be able to critically evaluate scientific articles. Evidence-based healthcare (EBH) can be defined as the link between good scientific research and clinical practice and systematic reviews constitute one of the forms of research excellence proposed within EBH. Systematic reviews employ rigorous methods that reduce the occurrence of bias. Systematic reviews with meta-analyses generally optimize the results found, because quantitative analysis of the studies included in the review yields additional information. In this paper, we will discuss how to interpret a meta-analysis and how to apply subset and sensitivity analysis strategies and we will also describe possible sources of heterogeneity and common errors that can affect a meta-analysis.

Rectal Biopsy Technique for the Diagnosis of Hirschsprung Disease in Children: A Systematic Review and Meta-Analysis.

ABSTRACT: The diagnosis of Hirschsprung disease (HD) depends on the histopathological analysis of rectal biopsies. This review aims to define the best rectal biopsy technique. A systematic literature review and proportional meta-analysis of the available case series studies of rectal biopsies were performed in this study. All case series with more than five rectal biopsies in children younger than 18 years of age suspected of HD that described at least one type of rectal biopsy were included. The studies that did not specify the rate of conclusive results and the rate of complications of the biopsy procedures were excluded. According to the literature review, there were four different techniques of rectal biopsy: open, suction, punch, and endoscopic. In the title and abstract screening process, we assessed 496 articles, 159 fulfilled the eligibility criteria, and 71 studies reported our outcomes of interest and were included in the meta-analysis. The pooled proportion of conclusive results was 94% in open biopsies (95% CI 0.89-0.98), 95% in punch (95% CI 0.90-0.98), and 88% in suction group (95% CI 0.85-0.92). The pooled proportion of complication rates was 2% in open biopsies (95% CI 0.00031-0.04), 0.039% in suction (95% CI 0.00023-0.0006), and 2% in punch biopsies (95% CI 0.00075-0.04). Suction, punch, and open techniques presented comparable rates of conclusive results. In the suction group, the association between different methods of histopathological analysis increased conclusive results rates; however, the punch biopsy was associated with significantly higher complication rates than the suction technique.

Risk of mortality and suicide associated with substance use disorder among healthcare professionals: A systematic review and meta-analysis of observational studies.

BACKGROUND: Previous studies have suggested that healthcare professionals may be susceptible to substance use disorders, and among the medical specialties, anaesthesia providers appear to be overrepresented. OBJECTIVE: We aimed to compare the prevalence of substance use-related mortality and suicides between anaesthesia and nonanaesthesia professionals. DESIGN: Systematic review of observational studies with meta-analyses. We defined anaesthesia providers as any healthcare professionals belonging to the specialty, regardless of age and duration of employment. Other healthcare professionals served as the control group. DATA SOURCES: Ovid Medline, EMBASE, Web of Science, Scopus, Scielo, LILACS and ProQuest databases up to March 2020. RESULTS: Thirty-nine studies were included, 31 cross-sectional studies involving 13 819 participants and eight cohorts with a total 129 811 participants proved eligible. Results suggested a higher rate of drug-related mortality with odds ratio (OR) 2.69 [95% confidence interval (CI), 1.80 to 4.00; P < 0.001; I2 = 0%, P = 0.55; high-certainty evidence] and suicide (OR 2.18, 95% CI, 1.33 to 3.58; P = 0.002; I2 = 0%, P = 0.68; moderate-certainty evidence) for anaesthesia providers compared with other healthcare professionals. CONCLUSION: High-to-moderate-certainty evidence shows that there is more than a two-fold increased rate of substance use-related mortality and suicide among anaesthesia providers compared with other healthcare professionals. Investigations examining substance abuse between healthcare professionals, with particular attention to working conditions and exposure are essential to further develop preventive strategies.

Red and Processed Meat Consumption and Risk for All-Cause Mortality and Cardiometabolic Outcomes: A Systematic Review and Meta-analysis of Cohort Studies.

This article has been corrected. The original version (PDF) is appended to this article as a Supplement. Background: Dietary guidelines generally recommend limiting intake of red and processed meat. However, the quality of evidence implicating red and processed meat in adverse health outcomes remains unclear. Purpose: To evaluate the association between red and processed meat consumption and all-cause mortality, cardiometabolic outcomes, quality of life, and satisfaction with diet among adults. Data Sources: EMBASE (Elsevier), Cochrane Central Register of Controlled Trials (Wiley), Web of Science (Clarivate Analytics), CINAHL (EBSCO), and ProQuest from inception until July 2018 and MEDLINE from inception until April 2019, without language restrictions, as well as bibliographies of relevant articles. Study Selection: Cohort studies with at least 1000 participants that reported an association between unprocessed red or processed meat intake and outcomes of interest. Data Extraction: Teams of 2 reviewers independently extracted data and assessed risk of bias. One investigator assessed certainty of evidence, and the senior investigator confirmed the assessments. Data Synthesis: Of 61 articles reporting on 55 cohorts with more than 4 million participants, none addressed quality of life or satisfaction with diet. Low-certainty evidence was found that a reduction in unprocessed red meat intake of 3 servings per week is associated with a very small reduction in risk for cardiovascular mortality, stroke, myocardial infarction (MI), and type 2 diabetes. Likewise, low-certainty evidence was found that a reduction in processed meat intake of 3 servings per week is associated with a very small decrease in risk for all-cause mortality, cardiovascular mortality, stroke, MI, and type 2 diabetes. Limitation: Inadequate adjustment for known confounders, residual confounding due to observational design, and recall bias associated with dietary measurement. Conclusion: The magnitude of association between red and processed meat consumption and all-cause mortality and adverse cardiometabolic outcomes is very small, and the evidence is of low certainty. Primary Funding Source: None. (PROSPERO: CRD42017074074).

Effect of Lower Versus Higher Red Meat Intake on Cardiometabolic and Cancer Outcomes: A Systematic Review of Randomized Trials.

This article has been corrected. The original version (PDF) is appended to this article as a Supplement. Background: Few randomized trials have evaluated the effect of reducing red meat intake on clinically important outcomes. Purpose: To summarize the effect of lower versus higher red meat intake on the incidence of cardiometabolic and cancer outcomes in adults. Data Sources: EMBASE, CENTRAL, CINAHL, Web of Science, and ProQuest from inception to July 2018 and MEDLINE from inception to April 2019, without language restrictions. Study Selection: Randomized trials (published in any language) comparing diets lower in red meat with diets higher in red meat that differed by a gradient of at least 1 serving per week for 6 months or more. Data Extraction: Teams of 2 reviewers independently extracted data and assessed the risk of bias and the certainty of the evidence. Data Synthesis: Of 12 eligible trials, a single trial enrolling 48 835 women provided the most credible, though still low-certainty, evidence that diets lower in red meat may have little or no effect on all-cause mortality (hazard ratio [HR], 0.99 [95% CI, 0.95 to 1.03]), cardiovascular mortality (HR, 0.98 [CI, 0.91 to 1.06]), and cardiovascular disease (HR, 0.99 [CI, 0.94 to 1.05]). That trial also provided low- to very-low-certainty evidence that diets lower in red meat may have little or no effect on total cancer mortality (HR, 0.95 [CI, 0.89 to 1.01]) and the incidence of cancer, including colorectal cancer (HR, 1.04 [CI, 0.90 to 1.20]) and breast cancer (HR, 0.97 [0.90 to 1.04]). Limitations: There were few trials, most addressing only surrogate outcomes, with heterogeneous comparators and small gradients in red meat consumption between lower versus higher intake groups. Conclusion: Low- to very-low-certainty evidence suggests that diets restricted in red meat may have little or no effect on major cardiometabolic outcomes and cancer mortality and incidence. Primary Funding Source: None (PROSPERO: CRD42017074074).

Reduction of Red and Processed Meat Intake and Cancer Mortality and Incidence: A Systematic Review and Meta-analysis of Cohort Studies.

This article has been corrected. The original version (PDF) is appended to this article as a Supplement. Background: Cancer incidence has continuously increased over the past few centuries and represents a major health burden worldwide. Purpose: To evaluate the possible causal relationship between intake of red and processed meat and cancer mortality and incidence. Data Sources: Embase, Cochrane Central Register of Controlled Trials, Web of Science, CINAHL, and ProQuest from inception until July 2018 and MEDLINE from inception until April 2019 without language restrictions. Study Selection: Cohort studies that included more than 1000 adults and reported the association between consumption of unprocessed red and processed meat and cancer mortality and incidence. Data Extraction: Teams of 2 reviewers independently extracted data and assessed risk of bias; 1 reviewer evaluated the certainty of evidence, which was confirmed or revised by the senior reviewer. Data Synthesis: Of 118 articles (56 cohorts) with more than 6 million participants, 73 articles were eligible for the dose-response meta-analyses, 30 addressed cancer mortality, and 80 reported cancer incidence. Low-certainty evidence suggested that an intake reduction of 3 servings of unprocessed meat per week was associated with a very small reduction in overall cancer mortality over a lifetime. Evidence of low to very low certainty suggested that each intake reduction of 3 servings of processed meat per week was associated with very small decreases in overall cancer mortality over a lifetime; prostate cancer mortality; and incidence of esophageal, colorectal, and breast cancer. Limitation: Limited causal inferences due to residual confounding in observational studies, risk of bias due to limitations in diet assessment and adjustment for confounders, recall bias in dietary assessment, and insufficient data for planned subgroup analyses. Conclusion: The possible absolute effects of red and processed meat consumption on cancer mortality and incidence are very small, and the certainty of evidence is low to very low. Primary Funding Source: None. (PROSPERO: CRD42017074074).

Patterns of Red and Processed Meat Consumption and Risk for Cardiometabolic and Cancer Outcomes: A Systematic Review and Meta-analysis of Cohort Studies.

This article has been corrected. The original version (PDF) is appended to this article as a Supplement. Background: Studying dietary patterns may provide insights into the potential effects of red and processed meat on health outcomes. Purpose: To evaluate the effect of dietary patterns, including different amounts of red or processed meat, on all-cause mortality, cardiometabolic outcomes, and cancer incidence and mortality. Data Sources: Systematic search of MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, CINAHL, Web of Science, and ProQuest Dissertations & Theses Global from inception to April 2019 with no restrictions on year or language. Study Selection: Teams of 2 reviewers independently screened search results and included prospective cohort studies with 1000 or more participants that reported on the association between dietary patterns and health outcomes. Data Extraction: Two reviewers independently extracted data, assessed risk of bias, and evaluated the certainty of evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. Data Synthesis: Eligible studies that followed patients for 2 to 34 years revealed low- to very-low-certainty evidence that dietary patterns lower in red and processed meat intake result in very small or possibly small decreases in all-cause mortality, cancer mortality and incidence, cardiovascular mortality, nonfatal coronary heart disease, fatal and nonfatal myocardial infarction, and type 2 diabetes. For all-cause, cancer, and cardiovascular mortality and incidence of some types of cancer, the total sample included more than 400 000 patients; for other outcomes, total samples included 4000 to more than 300 000 patients. Limitation: Observational studies are prone to residual confounding, and these studies provide low- or very-low-certainty evidence according to the GRADE criteria. Conclusion: Low- or very-low-certainty evidence suggests that dietary patterns with less red and processed meat intake may result in very small reductions in adverse cardiometabolic and cancer outcomes. Primary Funding Source: None. (PROSPERO: CRD42017074074).

Unprocessed Red Meat and Processed Meat Consumption: Dietary Guideline Recommendations From the Nutritional Recommendations (NutriRECS) Consortium.

This article has been corrected. The original version (PDF) is appended to this article as a Supplement. Description: Dietary guideline recommendations require consideration of the certainty in the evidence, the magnitude of potential benefits and harms, and explicit consideration of people's values and preferences. A set of recommendations on red meat and processed meat consumption was developed on the basis of 5 de novo systematic reviews that considered all of these issues. Methods: The recommendations were developed by using the Nutritional Recommendations (NutriRECS) guideline development process, which includes rigorous systematic review methodology, and GRADE methods to rate the certainty of evidence for each outcome and to move from evidence to recommendations. A panel of 14 members, including 3 community members, from 7 countries voted on the final recommendations. Strict criteria limited the conflicts of interest among panel members. Considerations of environmental impact or animal welfare did not bear on the recommendations. Four systematic reviews addressed the health effects associated with red meat and processed meat consumption, and 1 systematic review addressed people's health-related values and preferences regarding meat consumption. Recommendations: The panel suggests that adults continue current unprocessed red meat consumption (weak recommendation, low-certainty evidence). Similarly, the panel suggests adults continue current processed meat consumption (weak recommendation, low-certainty evidence). Primary Funding Source: None. (PROSPERO 2017: CRD42017074074; PROSPERO 2018: CRD42018088854).

Correction to: Methods for trustworthy nutritional recommendations NutriRECS (Nutritional Recommendations and accessible Evidence summaries Composed of Systematic reviews): a protocol.

Following publication of the original article [1], the authors reported a change in the 'Competing interests' section as described below.

Paraquat and Parkinson's disease: a systematic review and meta-analysis of observational studies.

This investigation aimed to conduct a systematic review of the literature and meta-analysis to determine whether exposure to the herbicide paraquat was associated with the development of Parkinson's disease (PD). Observational studies that enrolled adults exposed to paraquat with PD as the outcome of interest were searched in the PubMed, Embase, LILACS, TOXNET, and Web of Science databases up to May 2019. Two authors independently selected relevant studies, extracted data, and assessed methodological quality. The evidence certainty was assessed by the GRADE approach, which served as basis for a tentative causality assessment, supplemented by the Bradford Hill criteria when necessary. Results from nine case-control studies indicated that PD occurrence was 25% higher in participants exposed to paraquat. The only cohort investigation included demonstrated a non-significant OR of 1.08. Results from subgroup analyses also indicated higher PD frequency in participants that were exposed to paraquat for longer periods or individuals co-exposed with paraquat and any other dithiocarbamate. Data indicate apositive association between exposure to paraquat and PD occurrence, but the weight-of-evidence does not enable one to assume an indisputable cause-effect relationship between these two conditions. Better designed studies are needed to increase confidence in results. Systematic Review Registration: PROSPERO CRD42017069994.

Probiotics for the prevention of pediatric antibiotic-associated diarrhea.

BACKGROUND: Antibiotics alter the microbial balance commonly resulting in antibiotic-associated diarrhea (AAD). Probiotics may prevent AAD via providing gut barrier, restoration of the gut microflora, and other potential mechanisms of action. OBJECTIVES: The primary objectives were to assess the efficacy and safety of probiotics (any specified strain or dose) used for the prevention of AAD in children. SEARCH METHODS: MEDLINE, Embase, CENTRAL, CINAHL, and the Web of Science (inception to 28 May 2018) were searched along with registers including the ISRCTN and Clinicaltrials.gov. We also searched the NICE Evidence Services database as well as reference lists from relevant articles. SELECTION CRITERIA: Randomized, parallel, controlled trials in children (0 to 18 years) receiving antibiotics, that compare probiotics to placebo, active alternative prophylaxis, or no treatment and measure the incidence of diarrhea secondary to antibiotic use were considered for inclusion. DATA COLLECTION AND ANALYSIS: Study selection, data extraction, and risk of bias assessment were conducted independently by two authors. Dichotomous data (incidence of AAD, adverse events) were combined using a pooled risk ratio (RR) or risk difference (RD), and continuous data (mean duration of diarrhea) as mean difference (MD), along with corresponding 95% confidence interval (95% CI). We calculated the number needed to treat for an additional beneficial outcome (NNTB) where appropriate. For studies reporting on microbiome characteristics using heterogeneous outcomes, we describe the results narratively. The certainty of the evidence was evaluated using GRADE. MAIN RESULTS: Thirty-three studies (6352 participants) were included. Probiotics assessed included Bacillus spp., Bifidobacterium spp., Clostridium butyricum, Lactobacilli spp., Lactococcus spp., Leuconostoc cremoris, Saccharomyces spp., orStreptococcus spp., alone or in combination. The risk of bias was determined to be high in 20 studies and low in 13 studies. Complete case (patients who did not complete the studies were not included in the analysis) results from 33 trials reporting on the incidence of diarrhea show a precise benefit from probiotics compared to active, placebo or no treatment control.After 5 days to 12 weeks of follow-up, the incidence of AAD in the probiotic group was 8% (259/3232) compared to 19% (598/3120) in the control group (RR 0.45, 95% CI 0.36 to 0.56; I² = 57%, 6352 participants; NNTB 9, 95% CI 7 to 13; moderate certainty evidence). Nineteen studies had loss to follow-up ranging from 1% to 46%. After making assumptions for those lost, the observed benefit was still statistically significant using an extreme plausible intention-to-treat (ITT) analysis, wherein the incidence of AAD in the probiotic group was 12% (436/3551) compared to 19% (664/3468) in the control group (7019 participants; RR 0.61; 95% CI 0.49 to 0.77; P <0.00001; I² = 70%). An a priori available case subgroup analysis exploring heterogeneity indicated that high dose (≥ 5 billion CFUs per day) is more effective than low probiotic dose (< 5 billion CFUs per day), interaction P value = 0.01. For the high dose studies the incidence of AAD in the probiotic group was 8% (162/2029) compared to 23% (462/2009) in the control group (4038 participants; RR 0.37; 95% CI 0.30 to 0.46; P = 0.06; moderate certainty evidence). For the low dose studies the incidence of AAD in the probiotic group was 8% (97/1155) compared to 13% (133/1059) in the control group (2214 participants; RR 0.68; 95% CI 0.46 to 1.01; P = 0.02). Again, assumptions for loss to follow-up using an extreme plausible ITT analysis was statistically significant. For high dose studies the incidence of AAD in the probiotic group was 13% (278/2218) compared to 23% (503/2207) in control group (4425 participants; RR 0.54; 95% CI 0.42 to 0.70; P <0.00001; I² = 68%; moderate certainty evidence).None of the 24 trials (4415 participants) that reported on adverse events reported any serious adverse events attributable to probiotics. Adverse event rates were low. After 5 days to 4 weeks follow-up, 4% (86/2229) of probiotics participants had an adverse event compared to 6% (121/2186) of control participants (RD 0.00; 95% CI -0.01 to 0.01; P < 0.00001; I² = 75%; low certainty evidence). Common adverse events included rash, nausea, gas, flatulence, abdominal bloating, and constipation.After 10 days to 12 weeks of follow-up, eight studies recorded data on our secondary outcome, the mean duration of diarrhea; with probiotics reducing diarrhea duration by almost one day (MD -0.91; 95% CI -1.38 to -0.44; P <0.00001; low certainty evidence). One study reported on microbiome characteristics, reporting no difference in changes with concurrent antibiotic and probiotic use. AUTHORS' CONCLUSIONS: The overall evidence suggests a moderate protective effect of probiotics for preventing AAD (NNTB 9, 95% CI 7 to 13). Using five criteria to evaluate the credibility of the subgroup analysis on probiotic dose, the results indicate the subgroup effect based on high dose probiotics (≥ 5 billion CFUs per day) was credible. Based on high-dose probiotics, the NNTB to prevent one case of diarrhea is 6 (95% CI 5 to 9). The overall certainty of the evidence for the primary endpoint, incidence of AAD based on high dose probiotics was moderate due to the minor issues with risk of bias and inconsistency related to a diversity of probiotic agents used. Evidence also suggests that probiotics may moderately reduce the duration of diarrhea, a reduction by almost one day. The benefit of high dose probiotics (e.g. Lactobacillus rhamnosus orSaccharomyces boulardii) needs to be confirmed by a large well-designed multi-centered randomized trial. It is premature to draw firm conclusions about the efficacy and safety of 'other' probiotic agents as an adjunct to antibiotics in children. Adverse event rates were low and no serious adverse events were attributable to probiotics. Although no serious adverse events were observed among inpatient and outpatient children, including small studies conducted in the intensive care unit and in the neonatal unit, observational studies not included in this review have reported serious adverse events in severely debilitated or immuno-compromised children with underlying risk factors including central venous catheter use and disorders associated with bacterial/fungal translocation.

Methods for trustworthy nutritional recommendations NutriRECS (Nutritional Recommendations and accessible Evidence summaries Composed of Systematic reviews): a protocol.

BACKGROUND: Recent systematic reviews and editorials suggest that many organizations that produce nutritional guideline recommendations do not adhere to internationally recognized standards set forth by the Institute of Medicine (IoM), Guidelines International Network (GIN), Appraisal of Guidelines Research and Evaluation (AGREE), and Grading Recommendations, Assessment, Development and Evaluation (GRADE). METHODS: The potential solution is an independent group with content expertise and skilled in the methodology of systematic reviews and practice guidelines to produce trustworthy guideline recommendations, recommendations that are supported by publication in a top tier journal. The BMJ Rapid Recommendations project has recently demonstrated the feasibility and utility of this approach. Here, we are proposing trustworthy nutritional guideline recommendations based on internationally accepted guideline development standards, recommendations that will be informed by rigorous and novel systematic reviews of the benefits and harms associated with nutritional exposures, as well as studies on the values and preferences related to dietary behaviors among members of the international community. DISCUSSION: Adhering to international guideline standards, conducting high quality systematic reviews, and actively assessing the values and preferences of key stakeholders is expected to improve the quality of nutritional guidelines and their relevance to end-users, particularly patients and community members. We will send our work for peer review, and if found acceptable, we will publish our nutritional recommendations in top-tier general medicine journals.

Improving adherence to Standard Precautions for the control of health care-associated infections.

BACKGROUND: 'Standard Precautions' refers to a system of actions, such as using personal protective equipment or adhering to safe handling of needles, that healthcare workers take to reduce the spread of germs in healthcare settings such as hospitals and nursing homes. OBJECTIVES: To assess the effectiveness of interventions that target healthcare workers to improve adherence to Standard Precautions in patient care. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, two other databases, and two trials registers. We applied no language restrictions. The date of the most recent search was 14 February 2017. SELECTION CRITERIA: We included randomised trials of individuals, cluster-randomised trials, non-randomised trials, controlled before-after studies, and interrupted time-series studies that evaluated any intervention to improve adherence to Standard Precautions by any healthcare worker with responsibility for patient care in any hospital, long-term care or community setting, or artificial setting, such as a classroom or a learning laboratory. DATA COLLECTION AND ANALYSIS: Two review authors independently screened search results, extracted data from eligible trials, and assessed risk of bias for each included study, using standard methodological procedures expected by Cochrane. Because of substantial heterogeneity among interventions and outcome measures, meta-analysis was not warranted. We used the GRADE approach to assess certainty of evidence and have presented results narratively in 'Summary of findings' tables. MAIN RESULTS: We included eight studies with a total of 673 participants; three studies were conducted in Asia, two in Europe, two in North America, and one in Australia. Five studies were randomised trials, two were cluster-randomised trials, and one was a non-randomised trial. Three studies compared different educational approaches versus no education, one study compared education with visualisation of respiratory particle dispersion versus education alone, two studies compared education with additional infection control support versus no intervention, one study compared peer evaluation versus no intervention, and one study evaluated use of a checklist and coloured cues. We considered all studies to be at high risk of bias with different risks. All eight studies used different measures to assess healthcare workers' adherence to Standard Precautions. Three studies also assessed healthcare workers' knowledge, and one measured rates of colonisation with methicillin-resistant Staphylococcus aureus (MRSA) among residents and staff of long-term care facilities. Because of heterogeneity in interventions and outcome measures, we did not conduct a meta-analysis.Education may slightly improve both healthcare workers' adherence to Standard Precautions (three studies; four centres) and their level of knowledge (two studies; three centres; low certainty of evidence for both outcomes).Education with visualisation of respiratory particle dispersion probably improves healthcare workers' use of facial protection but probably leads to little or no difference in knowledge (one study; 20 nurses; moderate certainty of evidence for both outcomes).Education with additional infection control support may slightly improve healthcare workers' adherence to Standard Precautions (two studies; 44 long-term care facilities; low certainty of evidence) but probably leads to little or no difference in rates of health care-associated colonisation with MRSA (one study; 32 long-term care facilities; moderate certainty of evidence).Peer evaluation probably improves healthcare workers' adherence to Standard Precautions (one study; one hospital; moderate certainty of evidence).Checklists and coloured cues probably improve healthcare workers' adherence to Standard Precautions (one study; one hospital; moderate certainty of evidence). AUTHORS' CONCLUSIONS: Considerable variation in interventions and in outcome measures used, along with high risk of bias and variability in the certainty of evidence, makes it difficult to draw conclusions about effectiveness of the interventions. This review underlines the need to conduct more robust studies evaluating similar types of interventions and using similar outcome measures.

Monotherapy laser photocoagulation for diabetic macular oedema.

BACKGROUND: Diabetic macular oedema (DMO) is a complication of diabetic retinopathy and one of the most common causes of visual impairment in people with diabetes. Clinically significant macular oedema (CSMO) is the most severe form of DMO. Intravitreal antiangiogenic therapy is now the standard treatment for DMO involving the centre of the macula, but laser photocoagulation is still used in milder or non-central DMO. OBJECTIVES: To access the efficacy and safety of laser photocoagulation as monotherapy in the treatment of diabetic macular oedema. SEARCH METHODS: We searched CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; MEDLINE; Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 24 July 2018. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing any type of focal/grid macular laser photocoagulation versus another type or technique of laser treatment and no intervention. We did not compare laser versus other interventions as these are covered by other Cochrane Reviews. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Our primary outcomes were gain or loss of 3 lines (0.3 logMAR or 15 ETDRS letters) of best-corrected visual acuity (BCVA) at one year of follow-up (plus or minus six months) after treatment initiation. Secondary outcomes included final or mean change in BCVA, resolution of macular oedema, central retinal thickness, quality of life and adverse events, all at one year. We graded the certainty of the evidence for each outcome using the GRADE approach. MAIN RESULTS: We identified 24 studies (4422 eyes). The trials were conducted in Europe (nine studies), USA (seven), Asia (four) and, Africa (one), Latin America (one), Europe-Asian (one) and Oceania (one). The methodological quality of the studies was difficult to assess as they were poorly reported, so the predominant classification of bias was unclear.At one year, people with DMO receiving laser were less likely to lose BCVA compared with no intervention (risk ratio (RR) 0.42, 95% confidence interval (CI) 0.20 to 0.90; 3703 eyes; 4 studies; I2 = 71%; moderate-certainty evidence). There were also favourable effects observed at two and three years. One study (350 eyes) reported on partial or complete resolution of clinically significant DMO and found moderate-certainty evidence of a benefit at three years with photocoagulation (RR 1.55, 95% CI 1.30 to 1.86). Data on visual improvement, final BCVA, central macular thickness and quality of life were not available. One study related minor adverse effects on the central visual field and another reported one case of iatrogenic premacular fibrosis.Nine studies compared subthreshold versus standard macular photocoagulation (517 eyes). Subthreshold treatment was achieved with different methods of photocoagulation: non-visible conventional (two studies), micropulse (four) or nanopulse (one).Only one small study (29 eyes) reported on improvement or worsening of BCVA and estimates were very imprecise (improvement: RR 0.31, 95% CI 0.01 to 7.09; worsening: RR 0.93, 95% CI 0.15 to 5.76; very low-certainty evidence). All studies reported on continuous BCVA at one year; there was low-certainty evidence of no important difference between subthreshold and standard photocoagulation (mean difference (MD) in logMAR BCVA -0.02, 95% CI -0.07 to 0.03; 385 eyes; 7 studies; I2 = 42%), and were possibly different for different techniques (P = 0.07 and I2 = 61.5% for subgroup heterogeneity), with better results achieved with micropulse photocoagulation (MD -0.08 logMAR, 95% CI -0.16 to 0.0) as compared to the results achieved with nanopulse (MD 0.0 logMAR, 95% CI -0.06 to 0.06) and non-visible conventional (MD 0.04 logMAR, 95% CI -0.03 to 0.11), all of them compared to the standard lasers. One study reported partial to complete resolution of macular oedema at one year. There was low-certainty evidence of some benefit with standard photocoagulation, but estimates of effect were imprecise (RR 0.47, 95% CI 0.21 to 1.03; 29 eyes; 1 study). Studies also reported on the change in central macular thickness at one year and found moderate-certainty evidence of no important difference between subthreshold and standard photocoagulation (MD -9.1 µm, 95% CI -26.2 to 8.0; 385 eyes; 7 studies; I2 = 0%). There were no important adverse effects recorded in the studies.Nine studies compared argon laser versus another type of laser (997 eyes). There was moderate-certainty evidence of a small reduction or no difference between the interventions, with respect to improvement (RR 0.87, 95% CI 0.62 to 1.22; 773 eyes; 6 studies) and worsening of BCVA (RR 0.83, 95% CI 0.57 to 1.21; 773 eyes; 6 studies). Three studies reported few cases of subretinal fibrosis and neovascularization with argon laser and one study found subretinal fibrosis in the krypton group.One study (323 eyes) compared the modified ETDRS (mETDRS) grid technique with the mild macular grid (MMG), which uses mild, widely spaced burns throughout the macula. There was low-certainty evidence of an increased chance of visual improvement with MMG, but the estimate was imprecisely measured and the CIs include an increased risk or decreased risk of visual improvement at one year (RR 1.43, 95% CI 0.56 to 3.65; visual worsening: RR 1.40, 95% CI 0.64 to 3.05; change of logMAR visual acuity: MD -0.04 logMAR, 95% CI -0.01 to 0.09). There was a more significant reduction of central macular thickness with the mETDRS compared to the MMG technique (MD -34.0 µm, -59.8 to -8.3) in the MMG group. The study did not record important adverse effects. AUTHORS' CONCLUSIONS: Laser photocoagulation reduces the chances of visual loss and increases those of partial to complete resolution of DMO compared to no intervention at one to three years. Subthreshold photocoagulation, particularly the micropulse technique, may be as effective as standard photocoagulation and RCTs are ongoing to assess whether this minimally invasive technique is preferable to treat milder or non-central cases of DMO.

Noninvasive Brain Stimulations for Unilateral Spatial Neglect after Stroke: A Systematic Review and Meta-Analysis of Randomized and Nonrandomized Controlled Trials.

Background: Unilateral spatial neglect (USN) is the most frequent perceptual disorder after stroke. Noninvasive brain stimulation (NIBS) is a tool that has been used in the rehabilitation process to modify cortical excitability and improve perception and functional capacity. Objective: To assess the impact of NIBS on USN after stroke. Methods: An extensive search was conducted up to July 2016. Studies were selected if they were controlled and noncontrolled trials examining transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and theta burst stimulation (TBS) in USN after stroke, with outcomes measured by standardized USN and functional tests. Results: Twelve RCTs (273 participants) and 4 non-RCTs (94 participants) proved eligible. We observed a benefit in overall USN measured by the line bisection test with NIBS in comparison to sham (SMD -2.35, 95% CI -3.72, -0.98; p = 0.0001); the rTMS yielded results that were consistent with the overall meta-analysis (SMD -2.82, 95% CI -3.66, -1.98; p = 0.09). The rTMS compared with sham also suggested a benefit in overall USN measured by Motor-Free Visual Perception Test at both 1 Hz (SMD 1.46, 95% CI 0.73, 2.20; p < 0.0001) and 10 Hz (SMD 1.19, 95% CI 0.48, 1.89; p = 0.54). There was also a benefit in overall USN measured by Albert's test and the line crossing test with 1 Hz rTMS compared to sham (SMD 2.04, 95% CI 1.14, 2.95; p < 0.0001). Conclusions: The results suggest a benefit of NIBS on overall USN, and we conclude that rTMS is more efficacious compared to sham for USN after stroke.

Effects of different fresh gas flows with or without a heat and moisture exchanger on inhaled gas humidity in adults undergoing general anaesthesia: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: The minimum inhaled gas absolute humidity level is 20 mgH2O l for short-duration use in general anaesthesia and 30 mgH2O l for long-duration use in intensive care to avoid respiratory tract dehydration. OBJECTIVE: The aim is to compare the effects of different fresh gas flows (FGFs) through a circle rebreathing system with or without a heat and moisture exchanger (HME) on inhaled gas absolute humidity in adults undergoing general anaesthesia. DESIGN: Systematic review and meta-analyses of randomised controlled trials. We defined FGF (l min) as minimal (0.25 to 0.5), low (0.6 to 1.0) or high (≥2). We extracted the inhaled gas absolute humidity data at 60 and 120 min after connection of the patient to the breathing circuit. The effect size is expressed as the mean differences and corresponding 95% confidence intervals (CI). DATA SOURCES: PubMed, EMBASE, SciELO, LILACS and CENTRAL until January 2017. RESULTS: We included 10 studies. The inhaled gas absolute humidity was higher with minimal flow compared with low flow at 120 min [mean differences 2.51 (95%CI: 0.32 to 4.70); P = 0.02] but not at 60 min [mean differences 2.95 (95%CI: -0.95 to 6.84); P = 0.14], and higher with low flow compared with high flow at 120 min [mean differences 7.19 (95%CI: 4.53 to 9.86); P < 0.001]. An inhaled gas absolute humidity minimum of 20 mgH2O l was attained with minimal flow at all times but not with low or high flows. An HME increased the inhaled gas absolute humidity: with minimal flow at 120 min [mean differences 8.49 (95%CI: 1.15 to 15.84); P = 0.02]; with low flow at 60 min [mean differences 9.87 (95%CI: 3.18 to 16.57); P = 0.04] and 120 min [mean differences 7.19 (95%CI: 3.29 to 11.10); P = 0.003]; and with high flow of 2 l min at 60 min [mean differences 6.46 (95%CI: 4.05 to 8.86); P < 0.001] and of 3 l min at 120 min [mean differences 12.18 (95%CI: 6.89 to 17.47); P < 0.001]. The inhaled gas absolute humidity data attained or were near 30 mgH2O l when an HME was used at all FGFs and times. CONCLUSION: All intubated patients should receive a HME with low or high flows. With minimal flow, a HME adds cost and is not needed to achieve an appropriate inhaled gas absolute humidity.

Description of Malignancy Rates in Childhood- and Adult-Onset Systemic Lupus Erythematous by Proportional Meta-analysis.

OBJECTIVE: Describe malignancy rates in childhood onset and adult onset systemic lupus erythematous (SLE) by proportional meta-analysis. METHODS: Two reviewers screened data from PubMed (1966-2015), EMBASE (1980-2015), and LILACS (1982-2015) for SLE-associated malignancy. Proportional meta-analysis with a random-effects model and 95% confidence intervals (CIs) were calculated according to SLE onset age and mean follow-up time. Statistical difference was defined by 95% CI overlap. RESULTS: Overall the malignancy rate reported in 30 case series with 96,578 subjects was 3.4% (95% CI, 0.0260-0.0442; I = 97.6%; P < 0.0001). The malignancy rate was 4.2% (95% CI, 0.0318-0.0531; I = 98%; P < 0.0001) in 25 adult-onset SLE series, compared with 0.5% (95% CI, 0.0003-0.0154; I = 62.6%; P = 0.03) in 5 childhood-onset SLE series. Overall, in those with less than 5 years' follow-up, the malignancy rate was 2.8% (95% CI, 0.013-0.047; I = 91%; P < 0.0001) compared with 3.6% (95% CI, 0.0226-0.0531; I = 98.3%; P < 0.0001) in those with more than 5 years' follow-up, which was not significant, with 95% CI overlap. CONCLUSIONS: The meta-analysis indicated lower malignancy rates in pediatric-onset SLE compared with adult-onset SLE, but accrued data from childhood-onset SLE are still needed.

Efficacy and safety of blood transfusion in obstetric patients: systematic review of the literature.

OBJECTIVES: To evaluate the efficacy of blood transfusion compared to no intervention in obstetric patients. MATERIAL AND METHODS: A systematic review was performed with Cochrane Database of Clinical Trials, PubMed, EMBASE and LILACS databases searched as of September, 2016. Two authors independently selected relevant clinical trials, assessed their methodological quality and extracted data, using the GRADE approach. RESULTS: Five studies within a total of 6,297 met the inclusion criteria, with women generally aged 20-40 years. Three included studies allocated women to receive blood transfusion or no intervention. Two other studies allocated women with either restricted or full blood supplies. The major issue regarding risk of bias was the extent of concealment of randomization and blinding. There was no statistically significant difference between blood transfusion versus no transfusion or restricted blood supply on mortality (relative risk 0.82 [95% confidential interval 0.32 to 2.09], p = 0.68; two studies; I2 = not applicable). CONCLUSIONS: Very low-quality evidence suggests no significant difference between blood transfusion and no intervention in obstetric patients, underlining the need for more robust clinical trials evaluating this area.

Aspiration thrombectomy prior to percutaneous coronary intervention in ST-elevation myocardial infarction: a systematic review and meta-analysis.

BACKGROUND: Trials of aspiration thrombectomy (AT) prior to primary percutaneous intervention (PCI) in patients with ST-segment elevation MI (STEMI) have shown apparently inconsistent results and therefore generated uncertainty and controversy. To summarize the effects of AT prior to PCI versus conventional PCI in STEMI patients. METHODS: Searches of MEDLINE, EMBASE and CENTRAL to June 2015 and review of reference lists of previous reviews. We included randomized controlled trials (RCTs) comparing AT prior to PCI with conventional PCI alone. Pairs of reviewers independently screened eligible articles; extracted data; and assessed risk of bias. We used the GRADE approach to rate overall certainty of the evidence. RESULTS: Among 73 potential articles identified, 20 trials including 21,660 patients were eligible; data were complete for 20,866 patients. Moderate-certainty evidence suggested a non statistically significant decrease in overall mortality (risk ratio (RR) 0.89, 95 % confidence interval, 0.78 to 1.01, risk difference (RD) 4/1,000 over 6 months), no impact on recurrent MI (RR 0.94, 95 % CI, 0.79 to 1.12) or major bleeding (RR 1.02, 95 % CI, 0.78 to 1.35), and an increase in stroke (RR 1.56, 95 % CI, 1.09 to 2.24, RD 3/1,000 over 6 months). CONCLUSIONS: Moderate certainty evidence suggests aspiration thrombectomy is associated with a possible small decrease in mortality (4 less deaths/1000 over 6 months) and a small increase in stroke (3 more strokes/1000 over 6 months). Because absolute effects are very small and closely balanced, thrombectomy prior to primary PCI should not be used as a routine strategy.

Anticoagulant treatment for subsegmental pulmonary embolism.

BACKGROUND: Acute pulmonary embolism (PE) is a common cause of death, accounting for 50,000 to 200,000 deaths annually. It is the third most common cause of mortality among the cardiovascular diseases, after coronary artery disease and stroke.The advent of multi-detector computed tomographic pulmonary angiography (CTPA) has allowed better assessment of PE regarding visualisation of the peripheral pulmonary arteries, increasing its rate of diagnosis. More cases of peripheral PEs, such as isolated subsegmental PE (SSPE) and incidental PE, have thereby been identified. These two conditions are usually found in patients with few or none of the classic PE symptoms such as haemoptysis or pleuritic pain, acute dyspnoea or circulatory collapse. However, in patients with reduced cardio-pulmonary (C/P) reserve the classic PE symptoms can be found with isolated SSPEs. Incidental SSPE is found casually in asymptomatic patients, usually by diagnostic imaging performed for other reasons (for example routine CT for cancer staging in oncologic patients).Traditionally, all PEs are anticoagulated in a similar manner independent of the location, number and size of the thrombi. It has been suggested that many patients with SSPE may be treated without benefit, increasing adverse events by possible unnecessary use of anticoagulants.Patients with isolated SSPE or incidental PE may have a more benign clinical presentation compared with those with proximal PEs. However, the clinical significance in patients and their prognosis have to be studied to evaluate whether anticoagulation therapy is required.This review is an update of a Cochrane systematic review first published in 2014. OBJECTIVES: To assess the effectiveness and safety of anticoagulation therapy versus no intervention in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE. SEARCH METHODS: The Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched December 2015) and CENTRAL (2015, Issue 11). MEDLINE, EMBASE, LILACS and clinical trials databases were also searched. SELECTION CRITERIA: Randomised controlled trials of anticoagulation therapy versus no intervention in patients with SSPE or incidental SSPE. DATA COLLECTION AND ANALYSIS: Two review authors inspected all citations to ensure reliable selection. We planned for two review authors to independently extract data and to assess the methodological quality of identified trials using the criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions. MAIN RESULTS: No studies were identified that met the inclusion criteria. AUTHORS' CONCLUSIONS: There is no randomised controlled trial evidence for the effectiveness and safety of anticoagulation therapy versus no intervention in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE, and therefore we can not draw any conclusions. Well-conducted research is required before informed practice decisions can be made.