A Comparative Study Of Clinical Features Of Initial Seronegative Elderly-Onset Rheumatoid Arthritis And Polymyalgia Rheumatica

Objective: Senile-onset seronegative rheumatoid arthritis(SN-EORA)refers to rheumatoid arthritis that onset after the age of 60 years and no RF and anti-CCP antibodies are detected in the serum.Polymyalgia rheumatica(PMR)also begins after the age of 50 and peaks after the age of 60,and there is no RF and anti-CCP antibodies in the serum,both of which are common rheumatic diseases in the elderly population,and the clinical manifestations have many similarities,which often lead to clinical misdiagnosis.This retrospective study explores the differences in clinical features between SN-EORA and PMR to improve clinical understanding and differential diagnosis between SN-EORA and PMR.Methods: The clinical data of 83 patients with SN-EORA were retrospectively collected as the observation group,and 95 patients with isolated PMR(referring to those without giant cell arteritis after follow-up)were collected as the control group,including general demographic data,serum inflammatory indexes,joint involvement,imaging(MRI),etc.SPSS 23.0 statistical software was used to analyze the data by statistical methods such as t-test,Mann-Whitney U-test,X~2 test,logistic regression,ROC curve and so on.Result: There were 83 cases in the SN-EORA group,including 35 males and 48 females,male: female=1:1.37,and the median time from onset to presentation was 4.00(2.00,12.00)months;There were 95 cases in the PMR group,including 24 males and 71 females,and the median time from onset to presentation was 2.00(1.00,6.00)months.There were significant differences in the sex ratio and time to onset of diagnosis between the two groups(P<0.05),and there were no significant differences in fever,fatigue and weight loss in the SN-EORA group compared with the PMR group(P>0.05).The mean ESR of 58.41±32.29 mm/h in the SN-EORA group was significantly lower than that of 68.26±30.04 mm/h(P<0.05)in the PMR group,while the median RDW level was 13.80(12.90,14.80),the median NLR level was 4.17(2.67,5.50),and the median level of PLR in the SN-EORA group 234.17(138.18,343.00)were significantly higher than those in the isolated PMR group,with median RDW levels of 13.30(12.70,14.10),median NLR levels of 3.07(2.24,4.85)and median PLR levels of170.00(117.14,259.29),all of which were statistically significant(P<0.05).There was no significant difference between CRP,RBC,PLT,PDW,and MLR between the SN-EORA group and the PMR group(P>0.05).Anemia occurred in 61 patients(73.49%)in the SN-EORA group and 67(70.53%)in the PMR group,and there was no significant difference in the incidence of anemia between the two groups(P>0.05).The proportion of elbow,knee and ankle involvement in the SN-EORA group was significantly higher than that in the PMR group,while the proportion of shoulder,neck,back and hip involvement in the PMR group was significantly higher than that in the SN-EORA group,and the difference was statistically significant(P<0.05).Compared with the comorbidities of SN-EORA group and PMR group,24(28.92%)had hypertension in combination with SN-EORA,while 45(47.37%)had hypertension in combination with PMR,a statistically significant difference(P<0.05),and there was no significant difference between SN-EORA group and PMR group in combining coronary heart disease and diabetes(P>0.05).SN-EORA shoulder magnetic resonance 13 cases and PMR shoulder magnetic resonance 56 cases,although the incidence of shoulder cavity/synovial sac effusion,humeral bone marrow edema/small cyst lesions,supraspinatus/inferior spinatus muscle injury,and rotator cuff injury in the SN-EORA group was higher than that in the PMR group,and the incidence of subacromial deltoid effusion was lower than in the PMR group,but there were no significant differences in these differences(P>0.05).Binary logistic regression analysis was performed on the risk factors for the development of SN-EORA in men,long time from onset to presentation,elbow and ankle involvement(OR>1,P<0.05);Female,NLR,and hip involvement are risk factors for PMR(OR>1,P<0.05).ROC curve analysis compared SN-EORA and PMR shoulder MRI imaging showed that patients with SN-EORA were inclined to present with rotator cuff injury,supraspinatus/inferior muscle injury,and shoulder cavity/synovial sac effusion.Conclusion: For elderly patients with multiple arthralgias of unknown cause,if RF and anti-CCP antibodies are negative,when the appearance is:(1)the patient is male;(2)The time from onset to consultation was longer(median time 4 months);(3)involving the elbow and ankle joints;(4)Shoulder MRI with rotator cuff injury,supraspinatus/inferior muscle injury,shoulder cavity/synovial sac effusion,SN-EORA should be considered;When present:(1)the patient is female;(2)High neutrophil/lymphocyte ratio(NLR);(3)PMR should be considered when the hip joint is involved.Accurate differentiation between SN-EORA and PMR also requires comprehensive clinical evaluation and long-term follow-up.