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

Neurologist. 2020 May;25(3):39-48. doi: 10.1097/NRL.0000000000000269.


Introduction: 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.

Methods: 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.

Results: 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).

Conclusion: 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.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Brain Ischemia / complications
  • Brain Ischemia / epidemiology*
  • Cross-Sectional Studies
  • Female
  • Hospitalization / statistics & numerical data
  • Humans
  • Male
  • Middle Aged
  • Pneumonia / complications
  • Pneumonia / epidemiology*
  • Retrospective Studies
  • Risk Factors
  • Stroke / complications
  • Stroke / epidemiology*
  • Treatment Outcome
  • Young Adult