Ischemic ECG abnormalities are associated with an increased risk for death among subjects with COPD, also among those without known heart disease
Received 7 March 2017
Accepted for publication 24 June 2017
Published 22 August 2017 Volume 2017:12 Pages 2507—2514
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Richard Russell
Ulf Nilsson,1 Anders Blomberg,1 Bengt Johansson,1 Helena Backman,2 Berne Eriksson,3 Anne Lindberg1
1Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden; 2Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine, the OLIN Unit, Umeå University, Umeå, 3Krefting Research Centre, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
Abstract presentation: An abstract, including parts of the results, has been presented at an oral session at the European Respiratory Society International Conference, London, UK, September 2016.
Background: Cardiovascular comorbidity contributes to increased mortality among subjects with COPD. However, the prognostic value of ECG abnormalities in COPD has rarely been studied in population-based surveys.
Aim: To assess the impact of ischemic ECG abnormalities (I-ECG) on mortality among individuals with COPD, compared to subjects with normal lung function (NLF), in a population-based study.
Methods: During 2002–2004, all subjects with FEV1/VC <0.70 (COPD, n=993) were identified from population-based cohorts, together with age- and sex-matched referents without COPD. Re-examination in 2005 included interview, spirometry, and 12-lead ECG in COPD (n=635) and referents [n=991, whereof 786 had NLF]. All ECGs were Minnesota-coded. Mortality data were collected until December 31, 2010.
Results: I-ECG was equally common in COPD and NLF. The 5-year cumulative mortality was higher among subjects with I-ECG in both groups (29.6% vs 10.6%, P<0.001 and 17.1% vs 6.6%, P<0.001). COPD, but not NLF, with I-ECG had increased risk for death assessed as the mortality risk ratio [95% confidence interval (CI)] when compared with NLF without I-ECG, 2.36 (1.45–3.85) and 1.65 (0.94–2.90) when adjusted for common confounders. When analyzed separately among the COPD cohort, the increased risk for death associated with I-ECG persisted after adjustment for FEV1 % predicted, 1.89 (1.20–2.99). A majority of those with I-ECG had no previously reported heart disease (74.2% in NLF and 67.3% in COPD) and the pattern was similar among them.
Conclusion: I-ECG was associated with an increased risk for death in COPD, independent of common confounders and disease severity. I-ECG was of prognostic value also among those without previously known heart disease.
Keywords: COPD, ECG, ischemic heart disease, epidemiology, mortality