Risk Factors for Aspiration Pneumonia After Receiving Liquid-Thickening Recommendations

Otolaryngol Head Neck Surg. 2022 Jul;167(1):125-132. doi: 10.1177/01945998211049114. Epub 2021 Sep 28.


Objective: We examined the influence of liquid thickness levels on the frequency of liquid penetration-aspiration in patients with dysphagia and evaluated the clinical risk factors for penetration-aspiration and aspiration pneumonia development.

Study design: A case series.

Setting: Single-institution academic center.

Methods: We reviewed medical charts from 2018 to 2019. First, we evaluated whether liquid thickness levels influence the frequency of liquid penetration-aspiration in patients with dysphagia. Penetration-aspiration occurrence in a videofluoroscopic swallowing study was defined as Penetration-Aspiration Scale (PAS) scores ≥3. Second, the association between liquid thickness level and penetration-aspiration was analyzed, and clinical risk factors were identified. Moreover, clinical risk factors for aspiration pneumonia development within 6 months were investigated.

Results: Of 483 patients, 159 showed penetration-aspiration. The thickening of liquids significantly decreased the incidence of penetration-aspiration (P < .001). Clinical risk factors for penetration-aspiration were vocal fold paralysis (odds ratio [OR], 1.99), impaired laryngeal sensation (OR, 5.01), and a history of pneumonia (OR, 2.90). Twenty-three patients developed aspiration pneumonia while undertaking advised dietary changes, including liquid thickening. Significant risk factors for aspiration pneumonia development were poor performance status (OR, 1.85), PAS score ≥3 (OR, 4.03), and a history of aspiration pneumonia (OR, 7.00).

Conclusion: Thickening of liquids can reduce the incidence of penetration-aspiration. Vocal fold paralysis, impaired laryngeal sensation, and history of aspiration pneumonia are significant risk factors of penetration-aspiration. Poor performance status, PAS score ≥3, and history of aspiration pneumonia are significantly associated with aspiration pneumonia development following recommendations on thickening liquids.

Level of evidence: 3.

Keywords: dysphagia; penetration-aspiration; pneumonia; risk factors; thickened liquids.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Deglutition
  • Deglutition Disorders* / complications
  • Deglutition Disorders* / etiology
  • Fluoroscopy
  • Humans
  • Pneumonia, Aspiration* / epidemiology
  • Pneumonia, Aspiration* / etiology
  • Risk Factors
  • Video Recording
  • Vocal Cord Paralysis* / complications