[Analysis of characteristics of elderly patients admitted to an intensive care unit during six waves of the SARS-CoV-2 pandemic: Implications for medical care]. / Análisis de las características de los pacientes mayores que ingresaron en una unidad de cuidados intensivos durante las 6 olas de la pandemia por SARS-CoV-2: implicaciones para la atención médica.

ABSTRACT

OBJECTIVE: To analyze the characteristics of seriously ill elderly patients during the six waves of the COVID-19 pandemic. METHOD: Retrospective, observational and analytical study of patients over 70 years of age admitted to the ICU (March-2020 to March-2022). Patients were categorized into three groups based on age 70-74 years; 75-79 years; and >80 years. A descriptive and comparative analysis of the sample was initially performed; and a 28-, 60- and 90-day survival analysis using the Kaplan-Meier method. Multivariate survival analysis was performed by fitting a Cox model. RESULTS: Of 301 patients, the lowest number of admissions occurred during the first wave (20 (6%)), compared to the wave with the highest number of admissions the sixth wave (76 (25%)). The survival curves at 28 days, 60 days and 90 days showed a higher probability of survival in the younger age groups (P<.01 and P=.01, respectively). Troponin at admission (per unit, ng/l) showed a significant association with 28- and 60-day mortality (HR 1.00; 95% CI 1.00-1.01; P<.05). Taking the 1st wave of the pandemic as a reference, admission in the 3rd wave behaved as a protective factor against mortality at 28 and 60 days of follow-up (HR 0.18; 95% CI 0.02-0.64; P<.05; HR 0.13; 95% CI 0.02-0.64; P<.05, respectively). CONCLUSIONS: The time of admission and biomarkers, such as troponin, constitute prognostic markers independent of age in the elderly population.