The Value of NLR and PLR in the Diagnosis of Rheumatoid Arthritis Combined with Interstitial Lung Disease and Assessment of Treatment Effect: A Retrospective Cohort Study.

Abstract

Objective: This retrospective cohort study investigated the value of neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) in the diagnosis and treatment of rheumatoid arthritis complicated with interstitial lung disease (RA-ILD).

Methods: A total of 163 patients with newly diagnosed rheumatoid arthritis (RA) were enrolled, with 122 patients in the RA group and 41 patients in the RA-ILD group. The mean age of the RA group was 63.84 ± 8.53 years, with a male-to-female ratio of 14:47. The RA-ILD group had a mean age of 66.29 ± 12.72 years, with a male-to-female ratio of 13:28. During the 2-year follow-up period, 10 patients in the RA group developed interstitial lung disease (ILD).

Results: NLR and PLR were significantly higher in RA-ILD group than in RA group (p < 0.05). The optimal critical values of NLR and PLR for the diagnosis of RA-ILD were 3.15 and 152.62, the area under ROC curve was 0.615 and 0.61, the sensitivity was 72%, 62%, and the specificity was 54% and 64%. NLR and PLR were significantly increased after ILD during follow-up in RA patients but decreased after ILD in the predicted percentage of vital capacity (VC%), forced vital capacity (FVC%), forced expiratory volume in the first second (FEV1%) and carbon monoxide dispersion (DLcoSB%) (p < 0.05). Moreover, NLR and PLR decreased after treatment. While VC%, FVC%, FEV1%, and DLcoSB% increased after treatment (p < 0.05). NLR was negatively correlated with FVC% and DLcoSB% both before and after treatment. PLR was also significantly negatively correlated with FVC% and DLcoSB% before and after treatment (p < 0.05).

Conclusion: When NLR and PLR increase, we should be alert to the possibility of RA complicated with ILD, which can be used as an evaluation index of the treatment effect of RA-ILD.