Systemic inflammatory response index as an independent risk factor for ischemic stroke in patients with rheumatoid arthritis: a retrospective study based on propensity score matching

Objective To investigate the relationship between systemic inflammatory response index (SIRI) and ischemic stroke (IS) in rheumatoid arthritis (RA) patients. Methods Fifty-two RA patients with IS, who were admitted to Wujin Hospital Affiliated with Jiangsu University between 2015 and 2019, were selected as the study group, and 236 RA patients without IS were selected as the control group. Propensity score matching (PSM) function of SPSS 26.0 was used to carry out 1:1 propensity score matching for gender, age, blood pressure, blood glucose, blood lipid, and smoking history of patients in the two groups, and the caliper value was set as 0.02 to obtain covariate balanced samples between groups. When performing blood tests, the following are determined: rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), mean platelet volume (MPV), calculated SIRI = (neutrophil x monocyte)/lymphocyte, and completed 28-joint disease activity score (DAS28-CRP). The differences in inflammatory markers between the two groups were compared, the independent risk factors were analyzed by logistic regression, and the auxiliary diagnostic value was evaluated by the receiver operating characteristic (ROC) curve. Results A total of 48 pairs of patients were successfully matched. SIRI in the study group was higher than that in the control group (p < 0.05), and the mean platelet volume (MPV) was lower in the study group than in the control group (p < 0.05). SIRI, DAS28-CRP (r = 0.508, p < 0.01), ESR (r = 0.359, p < 0.05), and CRP (r = 0.473, p < 0.01) were positively correlated. Logistic regression analysis showed that SIRI was an independent IS risk factor in RA patients (odds ratio, 1.30; 95% confidence interval, approximately 1.008-1.678). The optimal threshold for SIRI-assisted diagnosis of patients with RA and IS was 1.62, the area under the ROC curve was 0.721 (p < 0.01), sensitivity was 54.17%, and specificity was 83.33%. Conclusion SIRI was independently associated with the occurrence of ischemic stroke in patients with RA. Thus, RA patients with elevated SIRI should be closely monitored.