Predictors of pneumonia on routine chest radiographs in patients with COPD: a post hoc analysis of two 1-year randomized controlled trials
Received 24 May 2017
Accepted for publication 25 August 2017
Published 8 January 2018 Volume 2018:13 Pages 189—201
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Charles Downs
Peer reviewer comments 3
Editor who approved publication: Dr Richard Russell
David B Rubin,1 Harris A Ahmad,2 Michael O’Neal,2 Sophie Bennett,3 Sally Lettis,3 Dmitry V Galkin,1 Courtney Crim1
1Respiratory R&D, GSK, Research Triangle Park, NC, 2Medical Affairs, Medical Imaging and Biomarkers, BioClinica Inc., Princeton, NJ, USA; 3Statistics and Programming, GSK, Stockley Park, Uxbridge, UK
Background: Patients with COPD are at risk for life-threatening pneumonia. Although anatomical abnormalities in the thorax may predispose to pneumonia, those abnormalities identified on routine chest X-rays (CXRs) in patients with COPD have not been studied to better understand pneumonia risk.
Methods: We conducted a post hoc exploratory analysis of data from two replicate year-long clinical trials assessing the impact of fluticasone furoate–vilanterol versus vilanterol alone on COPD exacerbations (GSK studies: HZC102871/NCT01009463 and HZC102970/NCT01017952). Abnormalities on baseline CXRs from 179 patients who developed pneumonia and 50 randomly selected patients who did not were identified by blinded consensus readings conducted by two radiologists. Positive and negative likelihood ratios and diagnostic odds ratios (ORs) were calculated to evaluate the markers for subsequent pneumonia development during the 1-year study period.
Results: Baseline characteristics distinguishing the pneumonia and non-pneumonia groups included a lower body mass index (24.9 vs 27.5 kg/m2, P=0.008), more severe airflow obstruction (mean post-bronchodilator forced expiratory volume in 1 second [FEV1]/forced vital capacity ratio: 42.3% vs 47.6%, P=0.003), and prior pneumonia (36% vs 20%, P=0.030). Baseline CXR findings with the highest diagnostic ORs were: elevated hemi-diaphragm (OR: 6.87; 95% CI: 0.90, 52.26), thick tracheal-esophageal stripe (OR: 4.39 [0.25, 78.22]), narrow cardiac silhouette (OR: 2.91 [0.85, 9.99]), calcified pleural plaque/mid-chest pleural thickening (OR: 2.82 [0.15, 53.76]), and large/prominent pulmonary artery shadow (OR: 1.94 [0.95, 3.97]). The presence of a narrow cardiac silhouette at baseline was associated with a statistically significant lower mean pre-bronchodilator FEV1 (P=0.040). There was also a trend for a lower mean pre-bronchodilator FEV1 in patients with a large/prominent pulmonary artery shadow at baseline (P=0.095).
Conclusion: Findings on routine CXR that relate to pathophysiological mechanisms of pneumonia could help determine pneumonia risk in patients with COPD.
Keywords: COPD, pneumonia, chest X-rays, predictors of risk
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