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.