HIGH VERSUS STANDARD DOSES OF CORTICOSTEROIDS IN COVID-19 PATIENTS WITH AN ACUTE RESPIRATORY DISTRESS SYNDROME: a controlled observational comparative study.

INTRODUCTIONDespite the increasing evidence of the benefit of corticosteroids for the treatment of moderate-severe Coronavirus disease 2019 (COVID-19) patients, no data are available about the potential role of high doses of steroids for these patients. METHODSAll consecutive confirmed COVID-19 patients admitted to a single center were selected, including those treated with steroids and an acute respiratory distress syndrome (ARDS). Patients were allocated to the high doses (HD, [≥]250mg/day of methylprednisolone) of corticosteroids or the standard doses (SD, [≤]1.5mg/kg/day of methylprednisolone) at discretion of treating physician. The primary endpoint was the mortality between both cohorts and secondary endpoints were the risk of need for mechanical ventilation (MV) or death and the risk of developing a severe ARDS. RESULTS573 patients were included: 428 (74.7%) men, with a median (IQR) age of 64 (54-73) years. In HD cohort, a worse baseline respiratory situation was observed and male sex, older age and comorbidities were significantly more common. After adjusting by baseline characteristics, HD were associated with a higher mortality than SD (adjusted-OR 2.46, 95% CI 1.58 - 3.83, p<0.001) and with an increased risk of needing MV or death (adjusted-OR 2.50, p=0.001). Conversely, the risk of developing a severe ARDS was similar between groups. Interaction analysis showed that HD increased mortality exclusively in elderly patients. CONCLUSIONOur real-world experience advises against exceeding 1-1.5mg/kg/day of corticosteroids for severe COVID-19 with an ARDS, especially in older subjects. This reinforces the rationale of modulating rather than suppressing immune responses in these patients. SUMMARYIn patients with severe COVID-19, high doses of corticosteroids are associated with a higher mortality and risk of need for mechanical ventilation or death compared to standard doses. This deleterious effect is mainly observed in the elderly.

FALSE-NEGATIVE RESULTS OF INITIAL RT-PCR ASSAYS FOR COVID-19: A SYSTEMATIC REVIEW

BackgroundA 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. MethodsWe 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 with the corresponding 95% CI 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. ResultsWe 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. ConclusionsThere is a 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 (certainty of evidence: very low). An update of this review when additional studies become available is warranted. Systematic review registrationProtocol available on the OSF website: https://osf.io/gp38w/

Variations in chemical sexual signals of Psammodromus algirus lizards along an elevation gradient may reflect altitudinal variation in microclimatic conditions.

Chemical signals used in intraspecific communication are expected to evolve or to show phenotipic plasticity to maximize efficacy in the climatic conditions of a given environment. Elevational environmental gradients in mountains provide a good opportunity to test this hypothesis by examining variation in characteristics of signals in species found across different elevations with different climatic conditions. We analyzed by gas chromatography-mass spectrometry (GC-MS) the lipophilic fraction of the femoral gland secretions of male lizards Psammodromus algirus (Fam. Lacertidae) from six localities located along a 2200 m elevational gradient at Sierra Nevada Mountains (SE Spain). There was elevational clinal variation in climatic variables, number of femoral pores and in the relative proportions of some classes of compounds (i.e., ethyl esters of fatty acids, waxy esters, and aldehydes) but not others. We discuss how this variation would result in different physicochemical properties of the entire femoral secretion, which might help optimize the efficacy of chemical signals under the particular microclimatic conditions at each elevation.