Martín, María CJurado, AuroraAbad-Molina, CristinaOrduña, AntonioYarce, OscarNavas, Ana MCunill, VanesaEscobar, DaniloBoix, FranciscoBurillo-Sanz, SergioVegas-Sánchez, María CJiménez-de Las Pozas, YeseniaMelero, JosefaAguilar, MartaSobieschi, Oana IrinaLópez-Hoyos, MarcosOcejo-Vinyals, GonzaloSan Segundo, DavidAlmeida, DeliaMedina, SilviaFernández, LuisVergara, EstherQuirant, BibianaMartínez-Cáceres, EvaBoiges, MarcAlonso, MartaEsparcia-Pinedo, LauraLópez-Sanz, CeliaMuñoz-Vico, JavierLópez-Palmero, SerafínTrujillo, AntonioÁlvarez, PaulaPrada, ÁlvaroMonzón, DavidOntañón, JesúsMarco, Francisco MMora, SergioRojo, RicardoGonzález-Martínez, GemaMartínez-Saavedra, María TGil-Herrera, JuanaCantenys-Molina, SergiHernández, ManuelPerurena-Prieto, JanireRodríguez-Bayona, BeatrizMartínez, AlbaOcaña, EstherMolina, Juan2025-01-072025-01-072021-05-201742-4933https://hdl.handle.net/10668/28339One 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. 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. 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.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Area under the curveCOVID-19Cut-off pointsImmunityImmunosenescenceLockdownLymphocytesRenin-angiotensin-aldosterone system inhibitorsSevere acute respiratory syndrome coronavirus 2research article34016150open access10.1186/s12979-021-00237-wPMC8134808https://immunityageing.biomedcentral.com/counter/pdf/10.1186/s12979-021-00237-whttps://pmc.ncbi.nlm.nih.gov/articles/PMC8134808/pdf