Predictors of Pneumonia in Adults With Lower Respiratory Tract Infections

oximeter on finger
oximeter on finger
Researchers identified 4 specific symptoms that could be the basis for a pneumonia diagnosis.

A pneumonia diagnosis could be made based on 4 specific symptoms alone, according to a study published in the European Respiratory Journal

Researchers identified 28,883 adults from 5222 medical practices in the United Kingdom, forming a prospective cohort to determine whether clinical features could predict radiograph-confirmed pneumonia in adults presenting with lower respiratory tract symptoms in routine primary care. An initial clinical assessment was performed, followed by a 30-day follow-up via chart review.

Study results demonstrated the independent predictors of definite or probable pneumonia confirmed by radiograph to be temperature >37.8oC (relative risk [RR], 2.6 [95% CI, 1.5-4.8]), crackles on auscultation (RR, 1.8 [95% CI, 1.1-3.0]), oxygen saturation <95% (RR, 1.7 [95% CI, 1.0-3.1]), and pulse >100 min-1 (RR, 1.9 [95% CI, 1.1-3.2]).

Further, these symptoms were found to have a predictive value of 20.2% (95% CI, 17.3-23.1) in patients later diagnosed with pneumonia. 

Researchers concluded that a temperature >37.8oC, crackles on auscultation, oxygen saturation <95%, and pulse >100 min-1 were 4 symptoms positively associated with a diagnosis of pneumonia in patients who presented with a lower respiratory tract infection. Therefore, clinicians should consider the use of pulse oximetry as an inexpensive tool that may be used to diagnose pneumonia in adult patients in the outpatient setting.

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The utilization of this tool could prevent severe complications secondary to delayed pneumonia diagnosis and treatment, prevent the unnecessary use of antibiotics, and accurately diagnose and treat patients who truly have pneumonia in a timely manner.


Moore M, Stuart B, Little P, et al. Predictors of pneumonia in lower respiratory tract infections: 3C prospective cough complication cohort study. Eur Respir J. 2017;50(5):1700434.