OBJECTIVE To review and critically appraise published and preprint reports of prediction models for diagnosing coronavirus disease 2019 (covid-19) in patients with suspected infection, for prognosis of patients with covid-19, and for detecting people in the general population at increased risk of becoming infected with covid-19 or being admitted to hospital with the disease. DESIGNLiving systematic review and critical appraisal. DATA SOURCESPubMed and Embase through Ovid, Arxiv, medRxiv, and bioRxiv up to 7 April 2020.Cite this as: BMJ 2020;369:m1328 http://dx.

BackgroundIndications for the use of negative pressure wound therapy (NPWT) are broad and include prophylaxis for surgical site infections (SSIs). While existing evidence for the effectiveness of NPWT remains uncertain, new trials necessitated an updated review of the evidence for the effects of NPWT on postoperative wounds healing by primary closure. ObjectivesTo assess the effects of negative pressure wound therapy for preventing surgical site infection in wounds healing through primary closure. Search methodsWe searched the Cochrane Wounds Specialised Register, CENTRAL, Ovid MEDLINE (including In-Process & Other Non-Indexed Citations), Ovid Embase, and EBSCO CINAHL Plus in February 2018. We also searched clinical trials registries for ongoing and unpublished studies, and checked reference lists of relevant included studies as well as reviews, meta-analyses, and health technology reports to identify additional studies. There were no restrictions on language, publication date, or setting. Selection criteriaWe included trials if they allocated participants to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with another type of NPWT. Data collection and analysisFour review authors independently assessed trials using predetermined inclusion criteria. We carried out data extraction, 'Risk of bias' assessment using the Cochrane 'Risk of bias' tool, and quality assessment according to GRADE methodology.

Objective to provide guidance for guideline developers on how to consider health equity at key stages of the guideline development process. Study Design and Setting literature review followed by group discussions and consensus building. Results The key stages at which guideline developers could consider equity include setting priorities, guideline group membership, identifying the target audience(s), generating the guideline questions, considering the importance of outcomes and interventions, deciding what evidence to include and searching for evidence, summarizing the evidence and considering additional information, wording of recommendations, and evaluation and use. We provide examples of how guidelines have actually considered equity at each of these stages. Conclusion Guideline projects should consider the above suggestions for recommendations that are equity-sensitive.

BackgroundPressure ulcers are a prevalent and global issue and support surfaces are widely used for preventing ulceration. However, the diversity of available support surfaces and the lack of direct comparisons in RCTs make decision-making difficult.ObjectivesTo determine, using network meta-analysis, the relative effects of different support surfaces in reducing pressure ulcer incidence and comfort and to rank these support surfaces in order of their effectiveness.MethodsWe conducted a systematic review, using a literature search up to November 2016, to identify randomised trials comparing support surfaces for pressure ulcer prevention. Two reviewers independently performed study selection, risk of bias assessment and data extraction. We grouped the support surfaces according to their characteristics and formed evidence networks using these groups. We used network meta-analysis to estimate the relative effects and effectiveness ranking of the groups for the outcomes of pressure ulcer incidence and participant comfort. GRADE was used to assess the certainty of evidence.Main resultsWe included 65 studies in the review. The network for assessing pressure ulcer incidence comprised evidence of low or very low certainty for most network contrasts. There was moderate-certainty evidence that powered active air surfaces and powered hybrid air surfaces probably reduce pressure ulcer incidence compared with standard hospital surfaces (risk ratios (RR) 0.42, 95% confidence intervals (CI) 0.29 to 0.63; 0.22, 0.07 to 0.66, respectively). The network for comfort suggested that powered active air-surfaces are probably slightly less comfortable than standard hospital mattresses (RR 0.80, 95% CI 0.69 to 0.94; moderate-certainty evidence).ConclusionsThis is the first network meta-analysis of the effects of support surfaces for pressure ulcer prevention. Powered active air-surfaces probably reduce pressure ulcer incidence, but are probably less comfortable than standard hospital surfaces. Most prevention evidence was of low or very low certainty, and more research is required to reduce these uncertainties.

Background Indications for the use of negative pressure wound therapy (NPWT) are broad and include prophylaxis for surgical site infections (SSIs). While existing evidence for the effectiveness of NPWT remains uncertain, new trials necessitated an updated review of the evidence for the effects of NPWT on postoperative wounds healing by primary closure. Objectives To assess the effects of negative pressure wound therapy for preventing surgical site infection in wounds healing through primary closure. Search methods We searched the Cochrane Wounds Specialised Register, CENTRAL, Ovid MEDLINE (including In-Process & Other Non-Indexed Citations), Ovid Embase, and EBSCO CINAHL Plus in February 2018. We also searched clinical trials registries for ongoing and unpublished studies, and checked reference lists of relevant included studies as well as reviews, meta-analyses, and health technology reports to identify additional studies. There were no restrictions on language, publication date, or setting. Selection criteria We included trials if they allocated participants to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with another type of NPWT. Data collection and analysis Four review authors independently assessed trials using predetermined inclusion criteria. We carried out data extraction, 'Risk of bias' assessment using the Cochrane 'Risk of bias' tool, and quality assessment according to GRADE methodology.

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To assess the comparative safety and efficacy of a new parenteral lipid emulsion containing soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOFlipid20%) for postoperative patients, a meta-analysis of randomized controlled trials (RCTs) was conducted. Six RCTs with a total of 306 patients were included in the analysis. The overall quality of evidence for each outcome was evaluated using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) software. Compared with a soybean-based (Lipoven20%) and a soybean- and olive oil-based (ClinOleic20%) lipid emulsion, SMOFlipid20% was associated with lower levels of hepatic enzymes, suggesting less toxicity. Changes in low-density lipoprotein triglyceride and C-reactive protein levels were also lower with SMOFlipid20% compared with Lipoven20%. Differences between SMOFlipid20% and a lipid emulsion containing medium- and long-chain triglycerides (MCT/LCT20%) were not statistically significant. For all trials, there were no significant differences in adverse events and length of hospital stay. The quality of evidence from the RCTs evaluating SMOF20% versus Lipoven20% was moderate, while most of the evidence from RCTs of SMOF20% versus ClinOleic20% and MCT/LCT20% lipid emulsions was low.

Background: Researchers advocate developing empirically-derived prognostic models to predict pressure ulcer risk. However, there remains a scarcity of evidence about the performance and clinical value of these models. Objectives: To identify and describe empirically-derived models for predicting pressure ulcer risk; to assess the predictive performance of these models; and to evaluate their clinical impact in reducing pressure ulcer incidence. Methods: We performed a comprehensive database search up to February 2017 and searched other resources to identify longitudinal studies that developed and/or validated prognostic models for predicting pressure ulcer risk and studies evaluating the clinical effects of such models. There were no language or publication date restrictions. Two reviewers independently conducted study selection. Using a pre-prepared data extraction form, one reviewer collected data on the characteristics and performance of the included models and assessed study risk of bias. A second reviewer checked all the data. Using narrative synthesis, we summarised the characteristics of the included studies and models. Using meta-analysis, we combined performance (discrimination and calibration) measurement statistics for relevant models. Results: We included 24 studies with 28 data sources in the review and identified 22 models that were developed using these data. Of the 22 models, only seven had further external validations (one model was validated twice). In development, a third of models used univariate analysis alone to identify statistically significant predictors for subsequent multivariable analysis; and nine of the 16 developed models were formed using stepwise selection processes in multivariable analysis. Missing data were often incompletely reported, and continuous predictors were correctly handled in only two models (e.g., using restricted cubic spline). Sample sizes of the model development studies were small with 13 models involving fewer than 10 events per variable. The risk of bias associated with the development of all 22 models and eight validations was judged as high or unclear. The predictive performance was reported as: c-statistic point estimates ranging from 0.65 to 0.89, and total Observed:Expected risk ratios between 0.94 and 1.00. Compared with heuristic tools, relevant included models had better discrimination and calibration. No eligible study was identified that evaluated the clinical impact of any included model. Conclusions: Whilst many prognostic models for predicting ulcer risk have been developed few have been validated. The methods used for model development are generally flawed which reduces the potential for using these models in practice. Future research should address these weaknesses.