Wednesday, November 13, 2013

Risk Factors for Aspiration Pneumonia- A Patient Phenotype

As a clinician I am always looking for clinical pearls. Here is a study that sought to characterize a patient 'phenotype' for aspiration pneumonia.

This was an observational study of 1348 patients hospitalized with community-acquired pneumonia in the United Kingdom. Patients "at risk" for aspiration pneumonia  chronic neurologic disorders, esophageal disorders and dysphagia, impaired conscious level, vomiting, or witnessed aspiration. 

Nearly 14% of the cohort were classified as "at risk of aspiration." These patients were older (median age, 74 years [interquartile range, 60-84] vs 66 years [interquartile range, 49-77]; P < .0001) and more likely to have comorbidities (chronic liver disease 11.3% vs 3.7%, P < .0001; congestive heart failure 28% vs 17.1%, P = .0004; and stroke 26.9% vs 9.5%, P < .0001). Patients at risk of aspiration pneumonia had a poorer short-term outcome (30-day mortality 17.2% vs 7.7%, P < .0001), but after adjusting for their greater severity of illness and comorbidities this difference was not significant (odds ratio 1.05; 95% confidence interval [CI], 0.63-1.76; P = .8). However, patients with aspiration risk factors were at greater risk of poor long-term outcomes with increased 1-year mortality (hazard ratio [HR], 1.73; 95% CI, 1.15-2.58), increased risk of rehospitalization (HR, 1.52; 95% CI, 1.21-1.91), and a strong association with recurrent admissions with pneumonia (HR, 3.13; 95% CI, 2.05-4.78) after multivariable adjustment

Using risk factors to identify patients at risk of aspiration pneumonia may give us a clinical 'phenotype' of patients with greater severity of disease and poorer long-term outcomes.

What value is this? Proving conclusively that an aspiration event caused pneumonia in clinical practice is generally not feasible. The study was also low yield with respect to microbiologic data. These data will likely not alter antibiotic management. However, a better understanding of aspiration risk and prognosis may guide discussions about realistic outcomes and limitation of treatments and may result in meaningful discussion on end of life care.