Association between chronic obstructive pulmonary disease and systemic inflammation: a systematic review and a meta-analysis.
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 (FEV(1)) or forced vital capacity (FVC), and levels of various systemic inflammatory markers: C-reactive protein (CRP), fibrinogen, leucocytes, tumour necrosis factor-alpha (TNF-alpha), 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-alpha 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.
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The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, St Paul's Hospital, Room 368A, 1081 Burrard Street, Vancouver, British Columbia, Canada V6A 1Y6.
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Senthilselvan
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D002097:C-Reactive Protein / Q000032:analysis; D016207:Cytokines / Q000097:blood; D005340:Fibrinogen / Q000032:analysis; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000150:complications*; D007962:Leukocytes; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000209:etiology*; D014797:Vital Capacity / Q000502:physiology
D016207:Cytokines; D005340:Fibrinogen; D002097:C-Reactive Protein