Stroke-Associated Pneumonia: A Retrospective Study of Risk Factors and Outcomes

Pneumonia is the most common complication after stroke, but our knowledge on risk factors and predictors of stroke-associated pneumonia (SAP) is limited. We sought to evaluate the predictors and outcomes of SAP among acute ischemic stroke (AIS) hospitalizations.

This is a cross-sectional study of the Nationwide Inpatient Sample database from the year 2003 to 2014. We identified adult hospitalizations with AIS using International Classification of Diseases, ninth revision, clinical modification (ICD-9-CM) codes. The SAP was identified by the presence of a secondary diagnosis of hospital-acquired pneumonia and ventilator-associated pneumonia. Multivariable survey logistic regression models were utilized to evaluate the predictors of SAP.

Overall, 4,224,924 AIS hospitalizations were identified, of which 149,169 (3.53%) had SAP. The prevalence of SAP decreased from 3.72% in 2003 to 3.17% in 2014 (P<0.0001). Mortality [17.12% vs. 4.77%; adjusted odds ratio (aOR): 1.71; P<0.0001] and morbidity (22.53% vs. 3.28%; aOR: 1.86; P<0.0001) were markedly elevated in SAP group compare to non-SAP group. The significant risk factors of pneumonia among AIS hospitalization were nasogastric tube (aOR: 1.21; P=0.0179), noninvasive mechanical ventilation (aOR: 1.65; P<0.0001), invasive mechanical ventilation (aOR: 4.09; P<0.0001), length of stay between 1 to 2 weeks (aOR: 1.99; P<0.0001), >2 weeks (aOR: 3.90; P<0.0001), hemorrhagic conversion (aOR: 1.17; P=0.0002), and epilepsy (aOR: 1.09; P=0.0009). Other concurrent comorbidities which increased the risk of SAP among AIS patients were acquired immune deficiency syndrome (aOR: 1.88; P<0.0001), alcohol abuse (aOR: 1.60; P=0.0006), deficiency anemia (aOR: 1.26; P<0.0001), heart failure (aOR: 1.62; P<0.0001), pulmonary disease (aOR: 1.73; P<0.0001), diabetes (aOR: 1.29; P=0.0288), electrolyte disorders (aOR: 1.50; P<0.0001), paralysis (aOR: 1.22; P<0.0001), pulmonary circulation disorders (aOR: 1.22; P<0.0001), renal failure (aOR: 1.12; P<0.0001), coagulopathy (aOR: 1.13; P=0.0006), and weight loss (aOR: 1.39; P<0.0001).

Our data underline the considerable epidemiological and prognostic impact of SAP in patients with AIS leading to higher mortality, morbidity, length of stay, and hospital cost despite advancements in care.