Evaluation of physiological variables determining time to mortality after stroke-associated pneumonia.

Abstract

Introduction Stroke-associated pneumonia (SAP) frequently complicates stroke and is associated with significant mortality. Clinicians often use physiological variables within the National Early Warning Score (NEWS) when diagnosing and prescribing antibiotics for SAP, but little is known of its association with mortality. We investigated the relationship of the NEWS 2 score and its components (respiratory rate, heart rate, temperature, oxygen requirement, oxygen saturation and alertness level) prior to antibiotic initiation, with time-to-mortality in SAP. Methods We included patients with SAP (n=389) from a single hyperacute stroke unit. Diagnosis of SAP was made if pneumonia occurred within 7 days of hospital admission. Kaplan-Meier survival curves were generated to assess NEWS 2 parameters influencing survival at pre-defined time periods (1 year and 5 years). The association of these parameters on time-to-mortality were analysed using multivariable Cox regression models to account for a set of pre-specified potential confounders. Results The median age was 80y (71y-87y) and median NIHSS was 7 (IQR 4-17). Mortality within 1 year was 52.4% and 65.8% within 5 years. In the multivariable analyses, time-to-mortality was independently associated with respiratory rate (HR 1.04, 95% CI 1.01 to1.08, p=0.009) and total NEWS 2 score (HR 1.13, 95% CI 1.06 to 1.21, p=<0.001). Conclusions In patients with SAP, higher respiratory rate and total NEWS 2 score prior to antibiotic initiation were independently associated with time-to-mortality. Further studies are warranted to identify potential opportunities for intervention and ultimately guide treatment to improve outcomes in SAP patients.