Clinical Characteristics and Risk Factors for Mortality of 4 865 Hospitalized COVID-19 Patients at Alternate Care Site in Mexico City

Background: The COVID-19 outbreak as an international health emergency has required the transformation of existing healthcare systems. The establishment of Alternate Care Sites (ACS) helped the most severely impacted countries expand their response capability, with varying degrees of success.Methods : A monocentric cohort study was conducted at Mexico City's Temporary Unit COVID-19 (UTC-19). Including patients older than 16 years, admitted between April 29, 2020, and May 18, 2021, with confirmatory testing using real-time reverse transcription-polymerase chain reaction (RT-PCR). The data collection process was facilitated using Research Electronic Data Capture (REDCap). Sociodemographic, clinical, and biochemical variables, as well as prognostic, treatment, and outcome scales, were included in the analysis. Chi-square tests were used for counts, analysis of variance, Welch's T-test for numerical parameters, and Wilcoxon test for position values. Probability ratios (odds ratio) were used on the variables in which there were differences in the proportion by death groups, and univariate and multivariate data were reviewed with the proposition of two models according to the nature of the data. Statistical analysis was performed using R software (version 3·6·3), and the epiR package.Findings: 4865 patients were included, with a mean age of 49·33 years ± SD 15·28 years (IQR 38 to 60 years); 50·53% women. The main comorbidities were obesity (39·94%), arterial hypertension (25·14%), and diabetes (21·52%). The most frequent clinical manifestations were headache (62·87%), myalgia (62·69%), and cough (61·97%). The mean time elapsed between the onset of symptoms and admission was 6·9 days. 19·58% of the patients required supplemental oxygen through high-flow nasal cannulas (HFNC), and 8·32% required invasive mechanical ventilation (IMV); 4·37% of the patients died. Factors that were independently and significantly associated with death included male gender (odds ratio [OR], 1·60; 95% CI: 1·21-2·13; p = 0·001), age ≥ 50 years (OR 14·75; 95 % CI: 9·01-26·11; p < 0·001), null or low schooling (OR 3·47, 95% CI: 1·30, 7·73; p = 0·005), have at least one comorbidity (OR 3·26; 95% CI: 2·27-4·83; p = 0·001), present atrial fibrillation (OR 22·14; 95% CI: 4·08-120·23; p < 0·001), and symptoms such as cough (OR 1·51; 95% CI: 1·13-2·07; p = 0·006) and arthralgias (OR 1·44; 95% CI: 1·09-1·91; p = 0·012). In the evaluations at the time of admission, having a high risk of progression with a CALL score ≥ 7 (OR 2·89; 95% CI: 1·78-4·50; p < 0·001), a PaO2 / FiO2 ratio ≤ 300 (OR 2·18; 95% CI: 1·62-2·96; p 10 × 103/ μL (OR 2·90; 95% CI: 2·04-4·05; p < 0·001), lymphocyte count ≤ 1 × 103/ μL ( OR, 4·24; 95% CI: 3·16-5·77; p 5 (OR 4·40; 95% CI: 3·32-5·87; p < 0·001), they also had a higher risk of death. In the multivariate analysis of biochemical and therapeutic characteristics, the lymphopenia ≤ 1 × 103/ μL (OR 1·91; 95% CI: 1·15-3·18; p = 0·012), and having required steroid treatment (OR 2·85; 95% CI: 1·57-5·47; p = 0·001), supplemental oxygen with high-flow nasal cannulas (OR 3·12; 95% CI: 1·99-4·97; p < 0·001) or merited invasive mechanical ventilation (OR 42·52; 95% CI: 27·39-67·93; p < 0·001), was significantly associated with an increased risk of death.Interpretation: UTC-19 was one of the ACS with the greatest infrastructure and operating time in the world, enabling the response capacity to be expanded during the pandemic's most critical phase in Mexico City. This study identified the clinical characteristics and risk factors for mortality associated with COVID-19, which enables the development of continuous preparedness actions and the improvement of the operational model while taking into consideration the social determinants of health emergencies.Funding Information: This work was supported by the National Institutes of Health (R21ES027087 Prada) and the Consejo Nacional de Ciencia y Tecnología (FOSISS 2017-289503 Prada).Declaration of Interests: The authors declare that no conflicting interests exist.Ethics Approval Statement: The study was performed following the guidelines of the General Health Law on Research for Health - Mexico, the Declaration of Helsinki, and the ICH-Good Clinical Practices. The study was approved by the Research Ethics Committee (FM / DI / 098/2020), of the Research Division of the National Autonomous University of Mexico.