Predicting pneumococcal community-acquired pneumonia in the emergency department

Abstract

The aim of this study was to quantify the value of clinical predictors available in the emergency department (ED) in predicting Streptococcus pneumoniae as the cause of community-acquired pneumonia (CAP). A prospective, observational, cohort study of patients with CAP presenting in the ED was performed. Pneumococcal aetiology of CAP was based on either bacteraemia, or S. pneumoniae being cultured from sputum, or urinary immunochromatographic assay positivity, or positivity of a novel serotype-specific urinary antigen detection test. Multivariate logistic regression was used to identify independent predictors and various cut-off values of probability scores were used to evaluate the usefulness of the model. Three hundred and twenty-eight (31.0%) of 1057 patients with CAP had pneumococcal CAP. Nine independent predictors for pneumococcal pneumonia were identified, but the clinical utility of this prediction model was disappointing, because of low positive predictive values or a small yield. Clinical criteria have insufficient diagnostic capacity to predict pneumococcal CAP. Rapid antigen detection tests are needed to diagnose S. pneumoniae at the time of hospital admission.

Pneumococcal and Legionella Urinary Antigen Tests in Community-acquired Pneumonia: Prospective Evaluation of Indications for Testing

“…The prevalence of pneumococcal urinary antigen detection in our study (4.2%) was lower than reported in some prior CAP studies [13][14][15]21]. Reasons for lower pneumococcal prevalence in the current study may be multifactorial, including patient enrollment after the introduction of widespread pneumococcal conjugate vaccine use; inclusion of patients with all-cause CAP, including those with no pathogen detected; and systematic urinary antigen testing in the study population that did not rely on a clinician's decision to obtain the test.…”

“…Most prior work suggests pneumococcal pneumonia cannot be accurately identified based on clinical features, because its presentation overlaps substantially with pneumonia of other etiologies [13]. Our study supports the notion that pneumococcal pneumonia cannot be prospectively identified based on clinical features alone.…”

“…In addition to recommendations in the IDSA/ATS CAP guidelines for UAT indications, we also evaluated other clinical characteristics that were identified in prior studies as potentially predictive of pneumococcal and Legionella CAP ( Supplementary Table 3) [7,[11][12][13][14][15][16][18][19][20][21]. These variables included age ≥65 years, fever, nausea, diarrhea, confusion, headache, hyponatremia (serum sodium < 130 mmol/L), severe CAP, and empiric use of broad-spectrum antibiotics.…”

“…These recommendations were based on expert opinions and have not been extensively evaluated since publication. Prior studies examining risk factors for positive SP and LP UATs have been retrospective and limited by indication biases, with UATs being ordered at the discretion of the treating clinician or local practice [5][6][7][8][9][10][11][12][13][14][15][16].…”

Community-acquired pneumonia

“…As a consequence misdiagnosis is common, and as clinical criteria alone are not predictive in identifying the causative organism [44] most patients are treated with broad-spectrum antibiotics that may encourage the spread of antibiotic resistance. The BinaxNOW urine antigen test (Alere, Waltham, Massachusetts, USA) is a rapid diagnostic test for S. pneumoniae infections that is routinely available in many hospitals.…”