Influence factors of extra-articular manifestations in rheumatoid arthritis

Background and objective - Extra-articular manifestations (EAMs) are serious outcomes or complications of rheumatoid arthritis (RA) with increasing mortality and morbidity. The purpose was to explore the factors influencing EAMs, tissue-specific/systemic EAMs, and the concurrence of several EAMs. Patients and methods - In total, 519 inpatients with RA were enrolled. The clinical characteristics, laboratory parameters, and medications of RA patients and the details of EAMs were recorded carefully. Differences between groups were examined by a Chi-square test, independent samples t test, one-way analysis of variance, Mann-Whitney U test, and Kruskal-Wallis H test. Binary and ordinal logistic regression analyses were performed to determine the relationship between influential factors and EAMs, tissue-specific/systemic EAMs, and the concurrence of several EAMs. Results - The morbidity of EAMs was 44.70%. Male sex, age, and traditional Chinese medicine (TCM) were independent influential factors of EAMs, and a number of statistically significant influence factors were found in the multivariate analysis of tissue-specific/systemic EAMs. Finally, age, CRP levels, number of RA-affected types of joints, and TCM were the factors that independently influenced the concurrence of several EAMs. Conclusion - Influential factors identified in this study could be recommended in clinical work, which is hopeful to decrease the morbidity and mortality of EAMs in RA.