Association Between Admission Diastolic Blood Pressure and Clinical Outcomes in Elderly Patients with Severe/Critical COVID-19: A Retrospective Cohort Study.

Background: Elderly patients aged ≥65 years remain disproportionately vulnerable to severe COVID-19, with 30-day mortality rates ranging from 32% to 59% during the Omicron wave despite the variant's reduced overall virulence. While blood pressure abnormalities are common in critically ill COVID-19 patients, the prognostic significance of admission diastolic blood pressure (DBP) as an independent predictor of short-term mortality in this population has not been systematically evaluated. Objective: To investigate the association between DBP and clinical outcomes in this vulnerable population. Methods: This retrospective cohort study included 240 consecutive elderly patients (aged ≥65 years) with severe/critical COVID-19 admitted to the Hospital from December 24, 2022 to January 24, 2023. Patients were categorized by admission DBP into three groups: hypotension (<70 mmHg), optimal range (70-89 mmHg), and poor control (≥90 mmHg). The primary outcome was 30-day mortality. Multivariable logistic regression analysis was performed to identify independent predictors of mortality. Results: The full predictive model incorporating admission DBP category, age, chronic kidney disease, secondary infection, and oxygen saturation demonstrated good discrimination (AUC 0.880, 95% CI: 0.832-0.926). The Hosmer-Lemeshow goodness-of-fit test yielded χ Conclusion: In elderly patients with severe/critical COVID-19, admission hypotension was a strong independent predictor of 30-day mortality. These findings suggest that careful blood pressure monitoring and avoidance of excessive DBP reduction may improve outcomes in this vulnerable population.