Inflammation and infections in unreported chronic obstructive pulmonary disease exacerbations

Abstract

Purpose: COPD patients often do not report acute exacerbations to healthcare providers – unreported exacerbations. It is not known whether variances in symptoms, airway obstruction, aetiology and inflammatory responses account for differences in reporting of COPD exacerbations. The aims of the study were to compare symptoms, lung function changes, aetiology and inflammatory markers between exacerbations that were reported to healthcare providers or treated, with those that were unreported and untreated.

Patients and methods: We recruited a cohort of COPD patients and collected clinical data and blood and airway samples when stable and during acute exacerbations. Virological and bacterial analyses were carried out and inflammatory markers measured.

Results: We found no differences in symptoms, lung function, incidence of infection and inflammatory markers between reported and unreported exacerbations. Subjects who reported all exacerbations had higher BODE scores, lower FEV₁ and more exacerbations compared with those who did not.

Conclusion: The failure to report exacerbations is not related to the severity, aetiology or inflammatory profile of the exacerbation. Patients with less severe COPD and less frequent exacerbations are less likely to report exacerbations. The decision to report an exacerbation is not an objective marker of exacerbation severity and therefore studies that do not count unreported exacerbations will underestimate the frequency of clinically significant exacerbations. A better understanding of the factors that determine non-reporting of exacerbations is required to improve exacerbation reporting.

Trial registration: ClinicalTrials.gov Identifier: NCT1376830. Registered June 17, 2011

Keywords:

• chronic obstructive pulmonary disease
• acute exacerbations, unreported exacerbations

Acknowledgments

This work was supported by an Imperial College Healthcare Trust Biomedical Research Centre grant (P33132), the Imperial College and National Institute of Health Research Biomedical Research Centre funding scheme, the National Institute of Health Research Senior Investigator Award, and the National Institute of Health Research Clinical Lecturer funding scheme.

Availability of data and materials

The data sets from this study are available from the corresponding author on reasonable request. They will be available for 5 years from publication.

Author contributions

PM and SLJ conceived and designed the study. PM, MAC, MBTT, LF, AS, VP, SLE, EB, TK and JA acquired and analyzed the data. PM and SLJ drafted the manuscript. All authors contributed toward data analysis, drafting and critically revising the paper, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

MAC was an employee of Chiesi when the manuscript was submitted. She was not an employee when the work was carried out and is no longer an employee of Chiesi. VP reports speaker fees from Chiesi and Pifzer, outside the submitted work. SLJ reports personal fees from Therapeutic Frontiers, Myelo Therapeutics Gbbh, Concert Pharmaceuticals, Bayer, Synairgen, Novartis, Boehringer Ingelheim, Chiesi, GSK, Sanofi Pasteur, Centocor, Aviragen, and resTORbio, outside the submitted work. In addition, SLJ has the following patents issued: GB 0405634.7; PCT/EP2003/007939; PCT/GB05/50031; 6779645.9; and 13305152. PM reports speakers fees from Astra Zeneca and Boehringer Ingelheim, outside the submitted work. The authors report no other conflicts of interest in this work.