Evaluation of red blood cell distribution width–platelet ratio as a predictor of adverse pregnancy outcomes and disease severity in systemic lupus erythematosus

Objective The red blood cell distribution width to platelet ratio (RPR) is known to reflect systemic inflammation. This study aimed to explore the predictive value of RPR for disease activity and adverse pregnancy outcomes (APOs) in pregnant women with systemic lupus erythematosus (SLE). Methods We retrospectively evaluated case data of all pregnant women with SLE managed at the First Affiliated Hospital of Zhengzhou University from January 2014 to March 2017. Correlations between RPR and SLE clinical disease activity, organ involvement, and maternal complications were analysed. Changes in the RPR and erythrocyte sedimentation rate (ESR) were observed before and after treatment. A receiver operating characteristic (ROC) curve was used to predict disease activity and APOs based on RPR. Results A total of 118 patients were enrolled, including 77 in the disease-active group and 41 in the disease-inactive group. The live birth rate was significantly higher in the disease-inactive group than in the disease-active group ( P < 0.001). Compared to the disease-inactive group, the number of patients with elevated RPR, anti-dsDNA antibody level, and ESR was significantly higher in the disease-active group, whereas their platelet-lymphocyte ratios and complement 3 and 4 levels were significantly lower. The disease-active group was more likely to experience APOs ( P < 0.001), mainly due to premature birth, low birth weight, and pregnancy loss. The ROC curve indicated that RPR had an effect on disease activity and APOs. Conclusion RPR can be used as a predictor of disease severity and APOs in pregnant women with SLE. Key Points • RPR positively correlated with SLEDAI; patients with elevated RPR have higher disease activity, more organ, and more maternal complications. • Monitoring RPR could better predict disease activity in pregnant patients with SLE and reduce the incidence of maternal complications and APOs.