Association between chronic obstructive pulmonary disease and systemic inflammation: a systematic review and a meta-analysis
- 1The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, Vancouver, British Columbia, Canada
- 2Department of Medicine (Pulmonary Division), University of British Columbia, Vancouver, British Columbia, Canada
- 3Department of Medicine, Pulmonary Division, University of Alberta, Edmonton, Alberta, Canada
- 4Department of Public Health Sciences, University of Alberta, Edmonton, Alberta, Canada
- Correspondence to:
Dr D D Sin
James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, St Paul’s Hospital, Room 368A, 1081 Burrard Street, Vancouver, BC, Canada V6A 1Y6;
- Received 28 November 2003
- Accepted 29 March 2004
Background: Individuals with chronic obstructive pulmonary disease (COPD) are at increased risk of cardiovascular diseases, osteoporosis, and muscle wasting. Systemic inflammation may be involved in the pathogenesis of these disorders. A study was undertaken to determine whether systemic inflammation is present in stable COPD.
Methods: A systematic review was conducted of studies which reported on the relationship between COPD, forced expiratory volume in 1 second (FEV1) or forced vital capacity (FVC), and levels of various systemic inflammatory markers: C-reactive protein (CRP), fibrinogen, leucocytes, tumour necrosis factor-α (TNF-α), and interleukins 6 and 8. Where possible the results were pooled together to produce a summary estimate using a random or fixed effects model.
Results: Fourteen original studies were identified. Overall, the standardised mean difference in the CRP level between COPD and control subjects was 0.53 units (95% confidence interval (CI) 0.34 to 0.72). The standardised mean difference in the fibrinogen level was 0.47 units (95% CI 0.29 to 0.65). Circulating leucocytes were also higher in COPD than in control subjects (standardised mean difference 0.44 units (95% CI 0.20 to 0.67)), as were serum TNF-α levels (standardised mean difference 0.59 units (95% CI 0.29 to 0.89)).
Conclusions: Reduced lung function is associated with increased levels of systemic inflammatory markers which may have important pathophysiological and therapeutic implications for subjects with stable COPD.
- COPD, chronic obstructive pulmonary disease
- CRP, C-reactive protein
- FEV1, forced expiratory volume in 1 second
- IL, interleukin
- TNF-α, tumour necrosis factor-α
DDS is supported by a New Investigator Award from the Canadian Institutes of Health Research and by the Glaxo-Smith-Kline/St Paul’s Hospital Foundation COPD Professorship