[Correlation between dyslipidemia and rheumatoid arthritis associated interstitial lung disease]

To study the correlation between dyslipidemia and rheumatoid arthritis associa-ted interstitial lung disease (RA-ILD) by retrospective analysis of the clinical data.

The clinical data of patients with rheumatoid arthritis (RA), who were hospitalized in the Department of Rheumatism and Immunology of Peking University Shenzhen Hospital from January 2015 to July 2020 and fulfilled the criteria of the 2010 Rheumatoid Arthritis Classification Criteria established by American College of Rheumatology/European League Against Rheumatism collaborative initiative, were collected and analyzed.

There were 737 RA patients included, of whom 282(38.26%)were with interstitial lung disease (ILD). The median time from the onset of the first RA-related clinical symptoms to the onset of ILD was 13 years (95%CI 11.33-14.67). By multivariate Logistic regression analysis, we found that low-density lipoprotein cholesterol (LDL-C) was an independent risk factor for RA-ILD (OR 1.452, 95%CI 1.099-1.918, P=0.009), whereas high-density lipoprotein cholesterol (HDL-C) was a protective factor for RA-ILD (OR 0.056, 95%CI 0.025-0.125, P < 0.001). The RA patients with high LDL-C or low HDL-C had higher incidence of ILD than that of the RA patients with normal LDL-C or HDL-C(57.45% vs. 36.96%, P < 0.001; 47.33% vs. 33.81%, P < 0.001, respectively). The median time of ILD onset in the RA patients with low HDL-C was shorter than that of the RA patients with normal HDL-C [10.0(95%CI 9.33-10.67)years vs.17.0 (95%CI 14.58-19.42) years, P < 0.001]. HDL-C level was negatively correlated with disease activity. Among the RA-ILD patients, the patients with low HDL-C had higher percentage of usual interstitial pneumonia (UIP) then that of the patients with normal HDL-C (60.00% vs. 53.29%, P=0.002). The RA-ILD patients with high LDL-C had higher incidence rate of decrease in forced vital capacity (FVC) than that of the RA-ILD patients with normal LDL-C (50.00% vs. 21.52%, P=0.015). The RA-ILD patients with low HDL-C had higher incidence rate of decrease in FVC (26.92% vs. 16.18%, P=0.003) and carbon monoxide diffusion (80.76% vs. 50.00%, P=0.010) than that of RA-ILD patients with normal HDL-C.

LDL-C was possibly a potential independent risk factor for RA-ILD. HDL-C was possibly a potential protective factor for RA-ILD. HDL-C level was negatively correlated with disease activity of RA. The median time of ILD onset in the RA patients with low HDL-C was significantly shorter than that of the RA patients with normal HDL-C.