Background: Cases with negative reverse transcription-polymerase chain reaction (RT-PCR) results at initial testing for suspicion of SARS-CoV-2 infection, and found to be positive in a subsequent test, are considered as RT-PCR false-negative cases. False-negative cases have important implications for COVID-19 management, isolation, and risk of transmission. We aimed to review and critically appraise evidence about the proportion of RT-PCR false-negatives at initial testing for COVID-19. Methods: We performed a systematic review and critical appraisal of literature with high involvement of stakeholders in the review process. We searched on MEDLINE, EMBASE, LILACS, the WHO database of COVID-19 publications, the EPPI-Centre living systematic map of evidence about COVID-19, and the living systematic review developed by the University of Bern (ISPM). Two authors screened and selected studies according to the eligibility criteria and collected data of included studies (no-independent verification). Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We calculated the false-negative proportion with the corresponding 95% CI using a multilevel mixed-effect logistic regression model using STATA 16. Certainty of the evidence about false-negative cases was rated using the GRADE approach for tests and strategies. The information is current up to 6 April 2020. Findings: Five studies enrolling 957 patients were included. All studies were affected by several biases and applicability concerns. Pooled estimation of false-negative proportion was 0.085 (95% CI= 0.034 to 0.196; tau-squared = 1.08; 95% CI= 0.27 to 8.28; p<0.001); however, this estimation is highly affected by unexplained heterogeneity, and its interpretation should be avoided. The certainty of the evidence was judged as very low, due to the risk of bias, indirectness, and inconsistency issues. Conclusions: The collected evidence has several limitations, including risk of bias issues, high heterogeneity, and concerns about its applicability. Nonetheless, our findings reinforce the need for repeated testing in patients with suspicion of SARS-Cov-2 infection given that up to 29% of patients could have an initial RT-PCR false-negative result. Systematic review registration: Protocol available on OSF website: https://osf.io/gp38w/

Background A false-negative case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is defined as a person with suspected infection and an initial negative result by reverse transcription-polymerase chain reaction (RT-PCR) test, with a positive result on a subsequent test. False-negative cases have important implications for isolation and risk of transmission of infected people and for the management of coronavirus disease 2019 (COVID-19). We aimed to review and critically appraise evidence about the rate of RT-PCR false-negatives at initial testing for COVID-19. Methods We searched MEDLINE, EMBASE, LILACS, as well as COVID-19 repositories, including the EPPI-Centre living systematic map of evidence about COVID-19 and the Coronavirus Open Access Project living evidence database. Two authors independently screened and selected studies according to the eligibility criteria and collected data from the included studies. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We calculated the proportion of false-negative test results using a multilevel mixed-effect logistic regression model. The certainty of the evidence about false-negative cases was rated using the GRADE approach for tests and strategies. All information in this article is current up to July 17, 2020. Results We included 34 studies enrolling 12,057 COVID-19 confirmed cases. All studies were affected by several risks of bias and applicability concerns. The pooled estimate of false-negative proportion was highly affected by unexplained heterogeneity (tau-squared = 1.39; 90% prediction interval from 0.02 to 0.54). The certainty of the evidence was judged as very low due to the risk of bias, indirectness, and inconsistency issues. Conclusions There is substantial and largely unexplained heterogeneity in the proportion of false-negative RT-PCR results. The collected evidence has several limitations, including risk of bias issues, high heterogeneity, and concerns about its applicability. Nonetheless, our findings reinforce the need for repeated testing in patients with suspicion of SARS-Cov-2 infection given that up to 54% of COVID-19 patients may have an initial false-negative RT-PCR (very low certainty of evidence). Systematic review registration Protocol available on the OSF website: https://tinyurl.com/vvbgqya.

This updated Cochrane review found no evidence to suggest that homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination should be used for preventing cardiovascular events. Furthermore, there is no evidence suggesting that homocysteine-lowering interventions are associated with an increased risk of cancer.

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Analysis 2.1. Comparison 2: Sensitivity analysis excluding studies that allowed the use of elastic stockings, Outcome 1: Oedema in the lower legs (dichotomous variable

BackgroundThe current EAACI/GA2LEN/EDF/WAO guideline for urticaria provide specific recommendations for the diagnostic workup and treatment of patients with chronic spontaneous urticaria (CsU). This study explored if physicians in Ecuador know these recommendations and implement them in their actual clinical practice for CsU.MethodsWe investigated physicians who treat CsU patients in a cross-sectional study using a standardized questionnaire. Descriptive statistics were employed, adjusted logistic regression was performed to assess the link of guideline knowledge and use of therapy.ResultsSeven hundred forty surveys were collected and analyzed. The mean age of physicians was 42.3 (±12.5) years. Most of the participants (65.1%) were general physicians (GP), 13.7% were pediatricians, 11.0% internists, 6.8% dermatologists or allergists (D/A). Only 18.8% knew the EAACI/GA2LEN/EDF/WAO guideline. 44.5% of GPs searched for CsU etiology in contrast to 90% of D/A. Most common diagnostic test was total serum IgE (83.5%). Most common first line symptomatic treatment was oral corticoids (46.3%), followed by second generation antihistamines (sgAHs, 36.8%). A/D prescribed more sgAHs (regular doses) (74.1 vs 28.6% of GP) (p < 0.05). Experience with omalizumab was reported only by 3.5%, of physicians, and higher rates among who were familiar with the guideline.ConclusionThis study shows that the knowledge of guideline recommendations in physicians who treat urticaria patients in Ecuador is low. The diagnostic workup and treatment of CsU patients are largely not in line with guideline recommendations in real life practice settings. We were able to compare results between German and Ecuadorian physicians and found that Ecuadorian physicians have lower awareness of the current guideline (33 vs 18%). Only one-third of physicians reported using regular doses of sgAHs as the first line treatment. Also, only 12.9% of physicians use sgAHs in higher doses and physicians still use fgAHs, particularly pediatricians (42.9%). Our results suggest that disparities in knowledge between physicians from different countries could influence the management of CsU. Knowledge of the guidelines is linked to better choices of treatments. Awareness of guidelines needs to be promoted for better management of chronic urticaria.Electronic supplementary materialThe online version of this article (doi:10.1186/s40413-017-0150-7) contains supplementary material, which is available to authorized users.

In recent years, the use of information and communication technologies (ICTs) has increased in various sectors, among which the healthcare service is no exception. However, studies have mostly focused on the use of ICTs among patients with chronic diseases, with few reports on the advantages and barriers of these technologies among physicians, particularly in Latin America. We designed this study to fill in the gap, as an objective assessment of the frequency of use, perceptions, and barriers of ICTs among physicians remains crucial for a successful implementation of these technologies into the mainstream medical practice. Methods: We conducted an anonymous cross-sectional survey-based study in 640 Ecuadorian physicians. The survey used consisted of 13 items and evaluated the frequency of use, perceptions, and barriers of ICTs among physicians. Chi-square tests for goodness of fit and independence were performed, whilst Phi coefficient was interpreted to assess the strength of associations. Fisher exact test was performed when required. Results: Over 90% of physicians reported the use of ICTs to message other colleagues and patients (p=0.000). While 89.5% of physicians used social media to interact with other colleagues, only 58.1% used them to interact with patients (p=0.000). Most participants reported the use of ICTs to search for academic information (p=0.000). Moreover, more than 80.0% agree that ICTs may be used to promote health and medical services, search new job opportunities, get involved in research projects and promote teamwork with colleagues. However, 83.6% of physicians expressed concerns about privacy and patient confidentiality, while 53.8% stated that they lacked the time to use ICTs. Conclusion: High usage of ICTs was found among Ecuadorian physicians. Younger physicians, with less postgraduate years, and non-specialists were more likely to have a positive perception toward ICTs. Privacy and patient confidentiality, followed by time management, were the most reported barriers in our study.

Background: Although cannabis and cannabinoids are widely used with therapeutic purposes, their claimed efficacy is highly controversial. For this reason, medical cannabis use is a broad field of research that is rapidly expanding. Our objectives are to identify, characterize, appraise, and organize the current available evidence surrounding therapeutic use of cannabis and cannabinoids, using evidence maps. Methods: We searched PubMed, EMBASE, The Cochrane Library and CINAHL, to identify systematic reviews (SRs) published from their inception up to December 2017. Two authors assessed eligibility and extracted data independently. We assessed methodological quality of the included SRs using the AMSTAR tool. To illustrate the extent of use of medical cannabis, we organized the results according to identified PICO questions using bubble plots corresponding to different clinical scenarios. Results: A total of 44 SRs published between 2001 and 2017 were included in this evidence mapping with data from 158 individual studies. We extracted 96 PICO questions in the following medical conditions: multiple sclerosis, movement disorders (e.g. Tourette Syndrome, Parkinson Disease), psychiatry conditions, Alzheimer disease, epilepsy, acute and chronic pain, cancer, neuropathic pain, symptoms related to cancer (e.g. emesis and anorexia related with chemotherapy), rheumatic disorders, HIV-related symptoms, glaucoma, and COPD. The evidence about these conditions is heterogeneous regarding the conclusions and the quality of the individual primary studies. The quality of the SRs was moderate to high according to AMSTAR scores. Conclusions: Evidence on medical uses of cannabis is broad. However, due to methodological limitations, conclusions were weak in most of the assessed comparisons. Evidence mapping methodology is useful to perform an overview of available research, since it is possible to systematically describe the extent and distribution of evidence, and to organize scattered data.