RESUMEN
BACKGROUND: Pandemic inter-wave hospital admissions and COVID-19-related mortality rates vary greatly. Some of the factors that may be playing part in this are the profile of the patients, viral variants, pharmacological treatments, or preventive measures. This work aimed to analyze the factors associated with mortality in COVID-19 patients admitted to hospital during 2020-2021. METHODS: Retrospective cohort study with COVID-19 patients admitted to Hospital de Barbastro (Spain) during 2020-2021. Data were collected from the Spanish Conjunto Mínimo Básico de Datos and microbiology and electronic prescription records. RESULTS: During the study period, 908 patients were consecutively admitted for COVID-19 (median age 70 years, 57.2% males); 162 (17.8%) patients died. We identified seven successive epidemiological waves. The following variables significantly associated to higher mortality: age, arterial hypertension, chronic renal failure, dementia, chronic obstructive pulmonary disease, heart failure, prior stroke, Charlson index, and wave 2; wave 4 was associated to greater survival. The multivariate analysis showed that age (OR=1.11; 95% CI: 1.09-1.14), chronic obstructive pulmonary disease (OR=2.33; 95% CI: 1.18-4.57), wave 2 (OR=2.57; 95% CI: 1.10-6.00), and wave 3 (OR=2.94; 95% CI: 1.17-7.38) associated with higher mortality. Glucocorticoid treatment was the only protective factor (OR=0.29; 95%CI: 0.14-0.62). CONCLUSIONS: This study confirms the therapeutic utility of glucocorticoids to reduce in-hospital mortality due to COVID-19. Heterogeneous mortality rates between the different COVID-19 waves suggest a direct role of viral variants as determinants of lethality, regardless of the patient's history.