Objectives To analyse the characteristics and predictors of death in hospitalized patients with coronavirus disease 2019 (COVID-19) in Spain. Methods A retrospective observational study was performed of the first consecutive patients hospitalized with COVID-19 confirmed by real-time PCR assay in 127 Spanish centres until 17 March 2020. The follow-up censoring date was 17 April 2020. We collected demographic, clinical, laboratory, treatment and complications data. The primary endpoint was all-cause mortality. Univariable and multivariable Cox regression analyses were performed to identify factors associated with death. Results Of the 4035 patients, male subjects accounted for 2433 (61.0%) of 3987, the median age was 70 years and 2539 (73.8%) of 3439 had one or more comorbidity. The most common symptoms were a history of fever, cough, malaise and dyspnoea. During hospitalization, 1255 (31.5%) of 3979 patients developed acute respiratory distress syndrome, 736 (18.5%) of 3988 were admitted to intensive care units and 619 (15.5%) of 3992 underwent mechanical ventilation. Virus- or host-targeted medications included lopinavir/ritonavir (2820/4005, 70.4%), hydroxychloroquine (2618/3995, 65.5%), interferon beta (1153/3950, 29.2%), corticosteroids (1109/3965, 28.0%) and tocilizumab (373/3951, 9.4%). Overall, 1131 (28%) of 4035 patients died. Mortality increased with age (85.6% occurring in older than 65 years). Seventeen factors were independently associated with an increased hazard of death, the strongest among them including advanced age, liver cirrhosis, low age-adjusted oxygen saturation, higher concentrations of C-reactive protein and lower estimated glomerular filtration rate. Conclusions Our findings provide comprehensive information about characteristics and complications of severe COVID-19, and may help clinicians identify patients at a higher risk of death.

Background The clinical presentation of COVID-19 in patients admitted to hospital is heterogeneous. We aimed to determine whether clinical phenotypes of patients with COVID-19 can be derived from clinical data, to assess the reproducibility of these phenotypes and correlation with prognosis, and to derive and validate a simplified probabilistic model for phenotype assignment. Phenotype identification was not primarily intended as a predictive tool for mortality. MethodsIn this study, we used data from two cohorts: the COVID-19@Spain cohort, a retrospective cohort including 4035 consecutive adult patients admitted to 127 hospitals in Spain with COVID-19 between Feb 2 and March 17, 2020, and the COVID-19@HULP cohort, including 2226 consecutive adult patients admitted to a teaching hospital in Madrid between Feb 25 and April 19, 2020. The COVID-19@Spain cohort was divided into a derivation cohort, comprising 2667 randomly selected patients, and an internal validation cohort, comprising the remaining 1368 patients. The COVID-19@HULP cohort was used as an external validation cohort. A probabilistic model for phenotype assignment was derived in the derivation cohort using multinomial logistic regression and validated in the internal validation cohort. The model was also applied to the external validation cohort. 30-day mortality and other prognostic variables were assessed in the derived phenotypes and in the phenotypes assigned by the probabilistic model. Findings Three distinct phenotypes were derived in the derivation cohort (n=2667)-phenotype A (516 [19%] patients), phenotype B (1955 [73%]) and phenotype C (196 [7%])-and reproduced in the internal validation cohort (n=1368)phenotype A (233 [17%] patients), phenotype B (1019 [74%]), and phenotype C (116 [8%]). Patients with phenotype A were younger, were less frequently male, had mild viral symptoms, and had normal inflammatory parameters. Patients with phenotype B included more patients with obesity, lymphocytopenia, and moderately elevated inflammatory parameters. Patients with phenotype C included older patients with more comorbidities and even higher inflammatory parameters than phenotype B. We developed a simplified probabilistic model (validated in the internal validation cohort) for phenotype assignment, including 16 variables. In the derivation cohort, 30-day mortality rates were 2•5% (95% CI 1•4-4•3) for patients with phenotype A, 30•5% (28•5-32•6) for patients with phenotype B, and 60•7% (53•7-67•2) for patients with phenotype C (log-rank test p<0•0001). The predicted phenotypes in the internal validation cohort and external validation cohort showed similar mortality rates to the assigned phenotypes (internal validation cohort: 5•3% [95% CI 3•4-8•1] for phenotype A, 31•3% [28•5-34•2] for phenotype B, and 59•5% [48•8-69•3] for phenotype C; external validation cohort: 3•7% [2•0-6•4] for phenotype A, 23•7% [21•8-25•7] for phenotype B, and 51•4% [41•9-60•7] for phenotype C).Interpretation Patients admitted to hospital with COVID-19 can be classified into three...

Aging is associated to disrupted contractility and rhythmicity, among other cardiovascular alterations. Drosophila melanogaster shows a pattern of aging similar to human beings and recapitulates the arrhythmogenic conditions found in the human heart. Moreover, the kinase CaMKII has been characterized as an important regulator of heart function and an arrhythmogenic molecule that participate in Ca2+ handling. Using a genetically engineered expressed Ca2+ indicator, we report changes in cardiac Ca2+ handling at two different ages. Aging prolonged relaxation, reduced spontaneous heart rate (HR) and increased the occurrence of arrhythmias, ectopic beats and asystoles. Alignment between Drosophila melanogaster and human CaMKII showed a high degree of conservation and indicates that relevant phosphorylation sites in humans are also present in the fruit fly. Inhibition of CaMKII by KN-93 (CaMKII-specific inhibitor), reduced HR without significant changes in other parameters. By contrast, overexpression of CaMKII increased HR and reduced arrhythmias. Moreover, it increased fluorescence amplitude, maximal rate of rise of fluorescence and reduced time to peak fluorescence. These results suggest that CaMKII in Drosophila melanogaster acts directly on heart function and that increasing CaMKII expression levels could be beneficial to improve contractility.

The Bowditch effect or staircase phenomenon is the increment or reduction of contractile force when heart rate increases, defined as either a positive or negative staircase. The healthy and failing human heart both show positive or negative staircase, respectively, but the causes of these distinct cardiac responses are unclear. Different experimental approaches indicate that while the level of Ca2+ in the sarcoplasmic reticulum is critical, the molecular mechanisms are unclear. Here, we demonstrate that Drosophila melanogaster shows a negative staircase which is associated to a slight but significant frequency-dependent acceleration of relaxation (FDAR) at the highest stimulation frequencies tested. We further showed that the type of staircase is oppositely modified by two distinct SERCA mutations. The dominant conditional mutation SERCAA617T induced positive staircase and arrhythmia, while SERCAE442K accentuated the negative staircase of wild type. At the stimulation frequencies tested, no significant FDAR could be appreciated in mutant flies. The present results provide evidence that two individual mutations directly modify the type of staircase occurring within the heart and suggest an important role of SERCA in regulating the Bowditch effect.

Medical uses of marijuana have been recently approved in many countries, and after a long ban on research, there is despicable scientific evidence regarding its action and side effects. We investigated the effect of inhalation of vaporized marijuana on cardiac function in Drosophila melanogaster, a suitable genetic model for assessing cardiovascular function. Chronic exposure of adult flies to vaporized marijuana reduces heart rate, increments contractility and prolongs relaxation. These changes are manifested in the cardiomyocytes with no effect in calcium handling, and in the absence of the canonical cannabinoids receptors identified in mammals.Our results are the first evidence of the in vivo impact of phytocannabinoids in D. melanogaster and open new paths for genetic screenings using vaporized compounds, providing a simple and affordable platform prior to mammalian models. Main Text:

We investigated the effect of inhalation of vaporized marijuana on cardiac function in Drosophila melanogaster, a suitable genetic model for studying human diseases. Adult flies were exposed to marijuana for variable time periods and the effects on cardiac function were studied. Short treatment protocol incremented heart-rate variability. Contractility was augmented only under prolonged exposure to cannabis and it was associated with incremented calcium transient within cardiomyocytes. Neither the activity of the major proteins responsible for calcium handling nor the calcium load of the sarcoplasmic reticulum were affected by the cannabis treatment. The observed changes manifested in the cardiomyocytes even in the absence of the canonical cannabinoid receptors described in mammals. Our results are the first evidence of the in vivo impact of phytocannabinoids in D. melanogaster. By providing a simple and affordable platform prior to mammalian models, this characterization of cardiac function under marijuana exposure opens new paths for conducting genetic screenings using vaporized compounds.

Studies about the relationship between substances consumed by humans and their impact on health, in animal models have been a challenge due to differences between species in the animal kingdom. However, the homology of certain genes has allowed extrapolating certain knowledge obtained in animals. Drosophila melanogaster, studied for decades, has been widely used as model for human diseases as well as to study responses associated with the consumption of several substances. In the present work we explore the impact of tobacco consumption on a model of "smoking flies". Throughout these experiments we aim to provide information about the effects of tobacco consumption on cardiac physiology. We assessed intracellular calcium handling, a phenomenon underlying cardiac contraction and relaxation. Flies chronically exposed to tobacco smoke exhibited an increased heart rate and alterations in the dynamics of the transient increase of intracellular calcium in myocardial cells. These effects were also evident under acute exposure to nicotine of the heart, in a semi-intact preparation. Moreover, the alpha 1 and 7 subunits of the nicotinic receptors are involved in the heart response to tobacco and nicotine under chronic (in the intact fly) as well as acute exposure (in the semi-intact preparation). The present data would help to understand the implication of the intracellular cardiac pathways affected by nicotine on the heart tissue. Based on the probed genetic and physiological similarity between the fly and human heart, cardiac effects exerted by tobacco smoke in Drosophila would help to know the impact of it in the human heart. Additionally, it may also provide information on how nicotine-like substances, e.g. neonicotinoids used as insecticides, affect cardiac function.

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