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 χ2=19.077 (P=0.015), and the optimal discrimination threshold determined by Youden's index yielded a sensitivity of 85.7% and a specificity of 84.6%.

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.