Cough reflex testing for dysphagia severity and pneumonia risk after acute stroke: a prospective observational study

Poststroke dysphagia and impaired cough reflex contribute to aspiration and pneumonia, yet the clinical value of cough reflex testing remains unclear.

In this prospective observational study, 395 patients who had an acute stroke admitted to an intensive care unit underwent fiberoptic endoscopic evaluation of swallowing and citric acid cough reflex testing at 0.4 mol/L. Dysphagia severity was rated using the Fiberoptic Endoscopic Dysphagia Severity Scale, with additional measures of secretion management, airway invasion and oral intake. Accuracy of cough reflex testing was calculated against fiberoptic endoscopic evaluation of swallowing. Ordinal and binary logistic regression assessed associations between cough reflex, dysphagia severity, pneumonia and mortality, including interactions.

Cough reflex testing showed 75% sensitivity and 55% specificity for silent aspiration and 78% sensitivity and 43% specificity for any aspiration. Absent or weakened cough reflex predicted severe dysphagia, impaired secretion management, increased aspiration risk, restricted oral intake and reduced spontaneous swallowing (p<0.001). Older age, stroke severity, impaired cough reflex and dysphagia severity predicted mortality. Preserved cough reduced pneumonia risk only in mild dysphagia.

Impaired cough reflex independently predicted poststroke dysphagia severity, impaired secretion management, aspiration risk, restricted oral intake and poorer functional outcome. Preserved cough conferred protection against pneumonia only in mild dysphagia, whereas in moderate to severe dysphagia aspiration burden and systemic vulnerability likely predominate, limiting clinical relevance of cough testing.

Cough reflex testing provides meaningful information on poststroke dysphagia severity and airway protection and may support risk stratification when instrumental swallowing assessment is unavailable.