Interleukin-6 is a Strong Predictor of the Frequency of COPD Exacerbation Within 1 Year

PURPOSE: Persistent chronic inflammation of chronic obstructive pulmonary disease (COPD) is associated with poor outcomes and frequently results in acute exacerbation. Predicting the number of exacerbations is important. Because interleukin 6 (IL-6) plays an important role in inducing and maintaining chronic inflammation, we sought to observe whether IL-6 measurement can predict the frequency of acute exacerbation of COPD. METHODS: We reviewed serum IL-6 concentrations of stable COPD patients from January 2016 to December 2017 and statistically analyzed them to determine the optimal threshold value to predict the frequency of COPD acute exacerbations. Outpatients with stable COPD were then recruited between January 2018 and December 2019 and grouped into a low IL-6 group and a high IL-6 group according to this threshold value. We then compared the number of exacerbations of COPD in 1 year between the two groups. RESULTS: We reviewed data from 95 COPD patients, who had a median of 1.00 exacerbations in preceding year; 35 of these patients had no fewer than two. The median IL-6 concentration was 8.80 pg/mL. IL-6 and hs-CRP were positively correlated with frequency of acute exacerbation in the preceding year, COPD assessment test (CAT) score and British medical research council (mMRC) score, and negatively correlated with forced expiratory volume in one second as percentage of predicted value (FEV(1)%pred) and FEV(1)/FVC% (forced vital capacity). IL-6 was the risk factor of COPD patients with two or more exacerbations in 1 year. Finally, we enrolled 65 COPD patients and divided into low IL-6 group and high IL-6 group; the high IL-6 group experienced more frequent exacerbations than did the low IL-6 group. CONCLUSION: An IL-6 measurement of 14.030 pg/mL or more is a risk factor for ≥2 acute exacerbations of COPD in the following year.