Abstract: Objective To analyze the clinical characteristics and influencing factors of the phenomenon of comorbidity of rheumatoid arthritis (RA) and osteoarthritis (OA) in women, so as to provide a basis for the prevention and treatment of OA and the management of comorbidity patients. 
Methods Detailed detailed medical records of 122 RA patients with OA treated at School of Clinical Medicine， Hainan Medical University/Hainan General Hospital were collected, and they were included in the case group. In the meantime, 70 simple RA patients were selected and included in the control group. The differences in clinical characteristics of the two groups were recorded and compared, and the influencing factors of comorbidity of RA and OA in females were further analyzed by multivariate Logistic regression analysis. A nomogram model was constructed according to the influencing factors of comorbidity of RA and OA. Bootstrap internal verification method and receiver operating characteristic (ROC) curve were used to verify the differentiation and clinical practicability of the model. 
Results Compared with the control group, the case group had a longer course of simple RA, higher body mass index (BMI), a higher proportion of physical labor and menopausal, higher levels of C-reactive protein (CRP), and lower levels of 25-hydroxyvitamin D3 ［25 (OH)D3］, with a significant difference (P＜0.05). Results of multivariate Logistic regression analysis showed that a long course of simple RA (95%CI: 1.044-1.350), high BMI (95%CI: 1.392-2.221), physical labor (95%CI: 1.040-9.182), menopausal (95%CI: 1.164-7.123), and high CRP levels (95%CI: 1.382-1.961) were risk factors for comorbidity of RA and OA in females, while high levels of 25 (OH) D3 (95%CI: 0.846-0.983) were protective factors for comorbidity of RA and OA in females (P＜0.05). Based on the above influencing factors, a nomogram model of comorbidity RA and OA in females was constructed. Bootstrap internal verification showed that the standard curve of the model was close to the Y-X straight line, with a consistency index of 0.922, indicating good discrimination of the model. The ROC curve was drawn, and the results showed that the area under the ROC curve for predicting comorbidity of RA and OA in females was 0.922, 95%CI: 0.883-0.961, and P＜0.001. 
Conclusion Female patients with comorbidity of RA and OA have a long course of simple RA, high BMI, a high proportion of physical labor and menopausal, high levels of CRP, and low levels of 25 (OH) D3. These characteristics are also important factors affecting comorbidity of RA and OA. A nomogram model constructed based on these influencing factors has good predictive value for comorbidity of RA and OA. 

Key words: arthritis, rheumatoid, osteoarthritis, comorbidity