The age again in the eye of the COVID-19 storm: evidence-based decision making
Authors: Martín María C. , Jurado Aurora , Abad-Molina Cristina , Orduña Antonio , Yarce Oscar , Navas Ana M. , Cunill Vanesa , Escobar Danilo , Boix Francisco , Burillo-Sanz Sergio , Vegas-Sánchez María C. , Jiménez-de las Pozas Yesenia , Melero Josefa , Aguilar Marta , Sobieschi Oana Irina , López-Hoyos Marcos , Ocejo-Vinyals Gonzalo , San Segundo David , Almeida Delia , Medina Silvia , Fernández Luis , Vergara Esther , Quirant Bibiana , Martínez-Cáceres Eva , Boiges Marc , Alonso Marta , Esparcia-Pinedo Laura , López-Sanz Celia , Muñoz-Vico Javier , López-Palmero Serafín , Trujillo Antonio , Álvarez Paula , Prada Álvaro , Monzón David , Ontañón Jesús , Marco Francisco M. , Mora Sergio , Rojo Ricardo , González-Martínez Gema , Martínez-Saavedra María T. , Gil-Herrera Juana , Cantenys-Molina Sergi , Hernández Manuel , Perurena-Prieto Janire , Rodríguez-Bayona Beatriz , Martínez Alba , Ocaña Esther , Molina Juan 
Published: May 2021

Abstract
Background
One hundred fifty million contagions, more than 3 million deaths and little more than 1 year of COVID-19 have changed our lives and our health management systems forever. Ageing is known to be one of the significant determinants for COVID-19 severity. Two main reasons underlie this: immunosenescence and age correlation with main COVID-19 comorbidities such as hypertension or dyslipidaemia. This study has two aims. The first is to obtain cut-off points for laboratory parameters that can help us in clinical decision-making. The second one is to analyse the effect of pandemic lockdown on epidemiological, clinical, and laboratory parameters concerning the severity of the COVID-19. For these purposes, 257 of SARSCoV2 inpatients during pandemic confinement were included in this study. Moreover, 584 case records from a previously analysed series, were compared with the present study data.

Results
Concerning the characteristics of lockdown series, mild cases accounted for 14.4, 54.1% were moderate and 31.5%, severe. There were 32.5% of home contagions, 26.3% community transmissions, 22.5% nursing home contagions, and 8.8% corresponding to frontline worker contagions regarding epidemiological features. Age > 60 and male sex are hereby confirmed as severity determinants. Equally, higher severity was significantly associated with higher IL6, CRP, ferritin, LDH, and leukocyte counts, and a lower percentage of lymphocyte, CD4 and CD8 count. Comparing this cohort with a previous 584-cases series, mild cases were less than those analysed in the first moment of the pandemic and dyslipidaemia became more frequent than before. IL-6, CRP and LDH values above 69 pg/mL, 97 mg/L and 328 U/L respectively, as well as a CD4 T-cell count below 535 cells/μL, were the best cut-offs predicting severity since these parameters offered reliable areas under the curve.

Conclusion
Age and sex together with selected laboratory parameters on admission can help us predict COVID-19 severity and, therefore, make clinical and resource management decisions. Demographic features associated with lockdown might affect the homogeneity of the data and the robustness of the results.