Laboratory Medicine ›› 2025, Vol. 40 ›› Issue (6): 525-533.DOI: 10.3969/j.issn.1673-8640.2025.06.002

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Roles of LDH,MO# and LMR in differential diagnosis of RA-ILD

WANG Li, TANG Ling, JIN Yaxiong, ZHANG Junlong, GAO Xuedan, NIU Qian()   

  1. Department of Clinical Laboratory,West China Hospital,Sichuan University,Chengdu 610041,Sichuan,China
  • Received:2024-06-04 Revised:2024-11-28 Online:2025-06-30 Published:2025-07-01
  • Contact: NIU Qian

Abstract:

Objective To assess the roles of routine laboratory indicators for the differential diagnosis of rheumatoid arthritis(RA)associated with interstitial lung disease(ILD). Methods Totally,80 patients with RA-ILD diagnosed at West China Hospital of Sichuan University from January 2014 to October 2021 were enrolled as RA-ILD group,and 89 patients with RA were enrolled as RA group. The general data and clinical laboratory routine determination results [complete blood count,anti-cyclic citrullinated peptide(CCP)antibody,rheumatoid factor(RF),C-reactive protein(CRP),erythrocyte sedimentation rate(ESR),lactate dehydrogenase(LDH)] were collected. Lymphocyte/monocyte ratio(LMR),neutrophil/lymphocyte ratio(NLR)and neutrophil/monocyte ratio(NMR)were calculated. They were classified according to genders,ages,anti-CCP antibodies and RF levels. The influencing factors of RA-ILD were evaluated by Logistic regression analysis. Receiver operating characteristic(ROC)curve was used to evaluate the differential diagnosis efficiency of RA-ILD. Results Compared with RA group,the level of LDH and the absolute value of monocytes (MO#) were increased in RA-ILD group,while LMR was decreased(P<0.05). There was no statistical significance for the other indicators(P>0.05). The changes in LDH and LMR were obvious in female subgroup and <60 years old subgroup. Elevated LDH,MO# and reduced LMR were risk factors for RA-ILD [odds ratios(OR) were 1.010,8.317 and 0.805,95% confidence intervals(CI)were 1.003-1.017,1.555-44.498 and 0.671-0.966,P<0.05]. The areas under curves(AUC)of LDH,MO# and LMR single and combined determinations for the differential diagnosis of RA-ILD were 0.697,0.611,0.633 and 0.744,respectively. LDH was more effective in the differential diagnosis of RA-ILD in female,<60 years old,or anti-CCP antibody <170 U·mL-1 patients. Conclusions Elevated LDH and MO#,as well as reduced LMR,are associated with an increased risk of RA-ILD,particularly in female patients or patients <60 years old. LDH,MO# and LMR may be used as the important and rapid tool for the differential diagnosis and risk prediction of RA-ILD.

Key words: Lactate dehydrogenase, Absolute value of monocytes, Lymphocyte/monocyte ratio, Rheumatoid arthritis, Interstitial lung disease

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