Serum C-reactive protein level and distribution in chronic obstructive pulmonary disease versus healthy controls: a case-control study from Iran.

Inflammation has a contributive role in the development and progression of chronic obstructive pulmonary disease (COPD).The present study was designed to determine the level and the distribution of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in COPD compared with controls. Ninety patients with COPD presented to an outpatient hospital clinic and 50 controls who were selected among personals of the same hospital entered the study. Serum high sensitive CRP (hs-CRP) was measured by immunoturbidimetric method and the ESR by Westergren method. Receiver operating characteristic curve was applied to determine a cutoff point for differentiation of the COPD and control group. In statistical analysis, the patients and controls were compared regarding levels and distribution of hs-CRP and ESR. Mean age of patients and controls was 67 ± 11.6 and 51.3 ± 6.7 years, respectively (p = 0.001). Mean hs-CRP was significantly higher (4.76 ± 5.6 vs 1.72 ± 1.68 mg/L, p = 0.001) but mean ESR was nonsignificantly higher (9.1 ± 11.2 vs 7.2 ± 7.4 m/h, p = 0.95) in patients than control. Serum hs-CRP at 1.55 mg/L, differentiated patients and controls at sensitivity of 77.3 % and specificity of 60 %. Serum hs-CRP >3 mg/L was observed in 39 (44.3 %) patients and 9 (18 %) controls (p = 0.001) and >6 mg/L in 22 (25 %) patients and 2 (4 %) controls (p = 0.001).Serum hs-CRP was significantly correlated with ESR in patient but not in control group (Spearman correlation coefficient = 0.516, p = 0.001). Serum hs-CRP and ESR was not correlated with age, weigh, smoking, and the severity of COPD. The results of this study indicated a systemic inflammatory process in COPD. Since inflammation has an important contribution in development of future pulmonary and extrapulmonary complications, serum CRP assessment will provide additional information beyond that achieved by conventional method of pulmonary function test.