Risk Factors Analysis for the Development of Hypocomplementemia in Rheumatoid Arthritis Patients: A Single-Center Retrospective Study

OBJECTIVE: The purpose of the research was to explore the possible risk factors for the development of hypocomplementemia (HC) in rheumatoid arthritis (RA) patients by analyzing their clinical and laboratory features. METHODS: This retrospective research contained 501 RA patients, divided into RA patients with HC (n=78) and RA patients without HC (n=423). Demographic characteristics and laboratory test results of RA patients were collected and analyzed, such as age, sex, anti-mutated citrullinated vimentin antibody (Anti-MCV), serum complements (C3, C4), immunoglobulins (IgA, IgG, IgM), hemoglobin (Hb), platelets (PLT) and erythrocyte sedimentation rate (ESR), etc. Spearman correlation was served as assessing the correlations of the levels of serum C3 and C4 with each index. Receiver operating characteristic (ROC) curves were served as assessing the diagnostic efficacy of each index for RA patients with HC. Furthermore, risk factors for the occurrence of HC in RA patients were analyzed by employing binary logistic regression of single and multiple factors. RESULTS: Compared RA patients with HC to without HC, the former were older and had a longer disease duration with increased levels of Anti-MCV, IgM and DAS28 and lower levels of Hb, PLT and ESR; Spearman correlation analysis verified the level of serum Anti-MCV was a negative correlation with C3 (r=−0.156); the area under the ROC curve (AUC) of PLT in diagnosing RA patients with HC was the largest at 0.65 (95% CI: 0.60–0.69); binary logistic regression analysis indicated that advanced age (>66 years), long disease duration (>62 months), high DAS28 value (>6.13), the levels of Anti-MCV>107.68IU/mL, IgM>1.54g/L, ESR≤69.00mm/h, Hb≤99.00g/L and PLT≤305.00×10(9)/L were probable risk factors for the occurrence of HC in RA patients. CONCLUSION: Age and disease duration, DAS28, Anti-MCV, IgM, ESR, Hb, and PLT are closely related to the development of HC in RA patients. Timely monitoring of these indicators can help to evaluate disease activity of RA patients and further improve their prognosis.