Plasma markers of inflammation and incidence of hospitalisations for COPD: results from a population-based cohort study

Background: The relationship between plasma markers of inflammation and the incidence of chronic obstructive pulmonary disease (COPD) is still unclear. This population-based study explored whether raised levels of five inflammation-sensitive plasma proteins (ISPs) predicted hospital admissions for COPD during 25 years of follow-up. Methods: Spirometric tests and measurements of five ISPs (fibrinogen, ceruloplasmin, alpha(1)-antitrypsin, haptoglobin, orosomucoid) were performed in 5247 apparently healthy men from the city of Malmo(mean age 46 years). The incidence of hospitalisations for COPD was studied in relation to the number of ISPs in the fourth quartile. Results: During the follow-up period, 258 men were admitted to hospital with COPD, 211 of whom were smokers at baseline. The incidence of hospital admissions for COPD was significantly associated with the number of raised ISPs. Adjusted for risk factors, the hazards ratio (95% CI) was 1.00 (reference), 1.28 (0.9 to 1.9), 1.29 (0.8 to 2.0) and 2.30 (1.6 to 3.2), respectively, for men with 0, 1, 2 and >= 3 ISPs in the top quartile (p for trend <0.001). This relationship was consistent in men with high and low lung function at baseline. The relationship with the incidence of hospital admissions for COPD was largely the same for all individual ISPs. Conclusion: Raised plasma ISP levels are associated with an increased incidence of COPD requiring hospitalisation.