Using Standardized Interpretation of Chest Radiographs to Identify Adults with Bacterial Pneumonia--Guatemala, 2007-2012.

Bacterial pneumonia is a leading cause of illness and death worldwide, but quantifying its burden is difficult due to insensitive diagnostics. Although World Health Organization (WHO) protocol standardizes pediatric chest radiograph (CXR) interpretation for epidemiologic studies of bacterial pneumonia, its validity in adults is unknown.Patients (age ≥ 15 years) admitted with respiratory infections to two Guatemalan hospitals between November 2007 and March 2012 had urine and nasopharyngeal/oropharyngeal (NP/OP) swabs collected; blood cultures and CXR were also performed at physician clinical discretion. 'Any bacterial infection' was defined as a positive urine pneumococcal antigen test, isolation of a bacterial pneumonia pathogen from blood culture, or detection of an atypical bacterial pathogen by polymerase chain reaction (PCR) of nasopharyngeal/oropharyngeal (NP/OP) specimens. 'Viral infection' was defined as detection of viral pathogens by PCR of NP/OP specimens. CXRs were interpreted according to the WHO protocol as having 'endpoint consolidation', 'other infiltrate', or 'normal' findings. We examined associations between bacterial and viral infections and endpoint consolidation.Urine antigen and/or blood culture results were available for 721 patients with CXR interpretations; of these, 385 (53%) had endpoint consolidation and 253 (35%) had other infiltrate. Any bacterial infection was detected in 119 (17%) patients, including 106 (89%) pneumococcal infections. Any bacterial infection (Diagnostic Odds Ratio [DOR] = 2.9; 95% confidence Interval (CI): 1.3-7.9) and pneumococcal infection (DOR = 3.4; 95% CI: 1.5-10.0) were associated with 'endpoint consolidation', but not 'other infiltrate' (DOR = 1.7; 95% CI: 0.7-4.9, and 1.7; 95% CI: 0.7-4.9 respectively). Viral infection was not significantly associated with 'endpoint consolidation', 'other infiltrate,' or 'normal' findings.'Endpoint consolidation' was associated with 'any bacterial infection,' specifically pneumococcal infection. Therefore, endpoint consolidation may be a useful surrogate for studies measuring the impact of interventions, such as conjugate vaccines, against bacterial pneumonia

Acute Respiratory Infection Case Definition^*.

<p>* Hospitalized patients were considered to have acute respiratory disease if they met one or more of the criteria for “evidence of acute infection” AND one or more of the criteria for “signs or symptoms of respiratory disease.”</p><p>Acute Respiratory Infection Case Definition^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133257#t001fn001" target="_blank">*</a>}.</p

Acute Respiratory Infection Case Definition^*.

<p>* Hospitalized patients were considered to have acute respiratory disease if they met one or more of the criteria for “evidence of acute infection” AND one or more of the criteria for “signs or symptoms of respiratory disease.”</p><p>Acute Respiratory Infection Case Definition^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133257#t001fn001" target="_blank">*</a>}.</p

Patient Demographic and Clinical Characteristics by WHO CXR Category.

<p>* Fisher’s exact test, except for median age which was performed using Mann-Whitney U test.</p><p>** Chronic conditions include asthma, diabetes, cancer, heart disease, chronic lung disease, chronic liver disease, and HIV/AIDS.</p><p>*** Oxygen saturation <90% or <88% in Quezaltenango.</p><p>Patient Demographic and Clinical Characteristics by WHO CXR Category.</p

Association between endpoint consolidation and different types of infections.

<p><b>*</b> Adjusted for age, sex, ethnicity, smoking status, presence of diabetes, and presence of asthma/chronic lung disease.</p><p>Association between endpoint consolidation and different types of infections.</p