Predictive Model Identifies Risk Factors for Bacteremia in Pneumococcal Pneumonia

Age younger than 65 years, hypoalbuminemia, a need for intensive respiratory or vasopressor support (IRVS), and high serum C-reactive protein (CRP) levels are independent risk factors for the development of bacteremia in patients with pneumococcal community-acquired pneumonia (CAP), according to an article published in BMC Pulmonary Medicine.

Using logistic regression models, Yasuyoshi Washio of the department of respiratory medicine at Saiseikai Fukuoka General Hospital, Fukuoka, Japan, and colleagues retrospectively analyzed data from 389 patients hospitalized with pneumococcal CAP between April 2007 and August 2015 at Kurashiki Central Hospital, Okayama, Japan, to determine risk factors for pneumococcal bacteremia. A receiver operating characteristic curve was used to devise a prediction model.

Forty-six patients (12%) developed bacteremia. Multivariate analysis identified age <65 years, serum albumin level <3.0 g/dL, need for IRVS, and C-reactive protein level >20 mg/dL as independent risk factors for the development of pneumococcal bacteremia. The bacteremia predictor score based on receiver operating characteristic curve analysis had a sensitivity of 0.74 and a specificity of 0.78 in patients with 2 risk factors. The area under the receiver operating characteristic curve was 0.77.

Younger age has previously been reported to be an independent risk factor for bacteremia in patients with CAP. The authors suggest that this may be because of poorer pneumococcal vaccination rates among younger patients in Japan. Increased frequency of mechanical ventilation and treatment for septic shock with vasopressor drugs were noted among those who developed bacteremia, as was an increase in intensive care unit admissions.

The study is limited by the inability to determine pneumococcal serotype or vaccination status and by its small size and retrospective design.

Antibiotic combination therapy has been reported to improve outcomes for patients with bacteremic pneumococcal CAP. The authors argued that as clinicians need to choose antibiotic therapy days before blood culture results are available, these results may help to identify at-risk patients who might benefit from antibiotic combination therapy. 

Reference

Washio Y, Ito A, Kumagai S, Ishida T, Yamazaki A. A model for predicting bacteremia in patients with community-acquired pneumococcal pneumonia: a retrospective observational study. BMC Pulmon Med. 2018:18:24.

This article originally appeared on Pulmonology Advisor