ObjectiveTo investigate the existence of persistent systemic inflammation (PSI) among patients with chronic obstructive pulmonary disease (COPD) in local areas, and identify the risk factors of PSI.MethodsA total of 150 patients with stable COPD and 70 non-smoking healthy individuals were enrolled in our study. The levels of interleukin-6 (IL-6), IL-18 and activin A in serum were detected. Pulmonary function was tested, and basic information of the candidates was acquired at the same time. All of the patients were followed-up at 6 months, 12 months and 24 months for two years. The value at the 95th percentile of the concentration of inflammation markers of non-smoking healthy samples was defined as the threshold value, also known as normal ceiling limit value. Existence of PSI was defined as the condition that two or more kinds of inflammation markers exceed the threshold at each follow-up visit. The COPD patients were categorized into three classes, in which there were respectively none, one and two or more kinds of inflammation markers with over-threshold values. Based on a 2-year followup, patients with two or more kinds of inflammation markers exceeding threshold values were classified as PSI subgroup, and patients without inflammation markers exceeding threshold values as never inflamed subgroup.ResultsThere were 22 patients (14.7%) had persistent systemic inflammation, whereas 60 patients (40.0%) did not show evidence of systemic inflammation. Single factor analysis of two subgroups showed that the patients in PSI subgroup had higher body mass index (BMI), higher smoking index, higher prior frequency of time to exacerbation, higher proportion of patients at high risk for recurrent acute exacerbation during 2-year followup, higher SGRQ total score, lower FEV1%pred and lower FEV1/FVC ratio significantly (all P<0.05). Higher BMI and higher risk of recurrent acute exacerbation were independent risk factors leading to PSI, of which the higher risk of recurrent acute exacerbation had a more important effect on PSI.ConclusionsSome COPD patients have PSI in this region, which may constitute a novel COPD phenotype (called systemic inflammatory phenotype). Higher BMI and higher risk of recurrent acute exacerbation are independent risk factors leading to PSI. Individualized treatment to prevent acute exacerbation and appropriate weight control may be a better intervention for these patients.
ObjectiveTo detect the level of oxidative stress markers in serum, including malondialdehyde (MDA), protein carbonyls (PC), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and total antioxidant capacity (TAC), in patients with stable chronic obstructive pulmonary disease (COPD), and explore the impacts of oxidant/antioxidant imbalance in pathogenesis of COPD. MethodsTwo hundred stable COPD patients (the COPD group) and 100 healthy individuals (the control group) were recruited in the study. The concentrations of MDA, PC, 8-OHdG and TAC in serum were detected. Pulmonary function test was performed and the general informations for each subjects were collected. The COPD patients were divided into a smoking subgroup and a non-smoking subgroup, or divided into a mild-moderate airflow limitation subgroup and a severe-extremely severe airflow limitation subgroup. ResultsThe levels of serum MDA, PC and 8-OHdG in the COPD group were significantly higher than those in the control group (all P < 0.01), but the level of serum TAC was significantly lower than that in the control group (P < 0.01). In the COPD patients, the levels of PC and 8-OHdG in the smoking subgroup were significantly higher than those in the non-smoking subgroup (both P < 0.05). The level of PC in the severe-extremely severe airflow limitation subgroup was significantly higher when compared with the mild-moderate airflow limitation subgroup (P < 0.01). Multiple linear regression analysis showed that the levels of PC and 8-OHdG were negatively related with FEV1% pred in the COPD patients, and the PC had greater impacts than 8-OHdG (β=-0.230, -0.219, P < 0.01). ConclusionSmoking can induce the abnormal increase of PC and 8-OHdG in serum which are negatively related with FEV1% pred in COPD patients, which suggests that oxidative stress might play an important role in pathogenesis of COPD.