Study On The Relationship Between The Ratio Of Fibrinogen To Prealbumin And Disease Activity In Patients With Systemic Lupus Erythematosus

Background:Systemic lupus erythematosus（SLE）is a diffuse connective tissue disease characterized by autoimmunity mediated by immune inflammation.The evaluation of systemic lupus erythematosus disease activity is very important for guiding treatment,monitoring disease and improving prognosis.At present,there are two main methods for evaluating the disease activity of SLE,the SLE Disease Activity Index 2000（SLEDAI-2000）and the British Island Lupus Assessment Group Index（BILAG-2004）.However,the above-mentioned disease activity assessment methods are cost-intensive.Repeated disease activity monitoring will bring a greater economic burden to patients.Therefore,simple,safe and reliable laboratory indicators are sought to evaluate systematic Lupus erythematosus disease activity is important.It has been found that peripheral blood inflammatory indicators such as neutrophil to lymphocyte ratio（NLR）are of great significance in evaluating SLE disease activity.The fibrinogen to prealbumin ratio（FPR）is a novel marker that comprehensively reflects the level of inflammation,coagulation and nutritional status of the body,has been paid much attention by researchers at home and abroad in recent years.Some studies have shown that high FPR is closely related to the mortality and increased risk of recurrence of various cancers,which is expected to become a reliable prognostic marker^[1].Some scholars have also found that FPR is closely related to the severity of chronic obstructive pulmonary disease^[2].Wang J et al^[3]found a good correlation between the inverse ratio of FPR and disease activity in rheumatoid arthritis.However,there are few literatures about FPR in SLE,and its clinical application value is unknown.Objective:The purpose of this study was to explore the clinical significance of fibrinogen to prealbumin ratio（FPR）in SLE,and to study the correlation between FPR and systemic lupus erythematosus disease activity and clinical indicators.The clinical application value of FPR and NLR in systemic lupus erythematosus disease activity assessment was compared.Method:A total of 79 patients with SLE who visited the Department of Rheumatology and Immunology in our hospital from January 2019 to September 2021 were selected as the research subjects,At the same time,70 healthy subjects were selected as the control group.all of whom met the diagnostic criteria for SLE revised by the American College of Rheumatology（ACR）in 1997.Activity index 2000（SLEDAI-2000）divided the patients into mild disease activity group（SLEDAI score<10points）,39 cases,and moderate-severe disease activity group（SLEDAI score≥10points）,40 cases.Other clinical indicators,and the Spearman correlation analysis method was used to study the correlation between FPR and NLR values,disease activity and clinical indicators in patients with SLE.The ROC curve of subjects was drawn to evaluate and compare the value of FPR and NLR in predicting the disease activity of systemic lupus erythematosus.Result:1.There were 79 SLE patients,including 7 males,accounting for 8.9%,and 72females,accounting for 91.1%.Age was 40±9.76 years;disease duration was 5（1,10）years.Among the 79 SLE patients,the most prominent clinical manifestations were rash（53.2%）,blood system involvement（46.8%）and kidney involvement（35.4%）,fever（35.4%）,arthritis（31.6%）,followed by serositis（17.7%）,lung involvement（12.7%）,oral ulcers（12.7%）,cardiovascular system involvement（11.4%）,while nervous system involvement and digestive system involvement were less common,2.5%and 0%,respectively.2.There was no significant difference in the age and sex composition ratio between SLE patients and healthy controls（p>0.05）,and comparability was considered.Compared with the healthy control group,the level of fibrinogen in SLE patients was increased,and the difference was statistically significant（p<0.05）,and the levels of white blood cell count,lymphocyte count,platelet,prealbumin,total protein,albumin,and globulin were decreased.,the difference was statistically significant（p<0.05）;other indicators such as neutrophil count,red blood cell distribution width were not significantly different（p>0.05）.The levels of FPR and NLR in SLE patients were significantly higher than those in healthy controls,and the difference was statistically significant（p<0.05）.3.The levels of fibrinogen,creatinine,uric acid,ESR,and CRP in the lupus patients in the moderate-severe disease activity group were higher than those in the mild disease activity group,and the difference was statistically significant（p<0.05）,lymphocyte count,prealbumin,total protein,albumin,C3,C4 levels decreased,and the difference was statistically significant（p<0.05）.4.Taking FPR and NLR as dependent variables,Spearman correlation analysis was performed.The results showed that FPR was positively correlated with SLEDAI score,CRP and ESR（p<0.05）,but had no correlation with complement C3 and C4（p>0.05）;NLR was positively correlated with ESR and SLEDAI score（p<0.05）,but had no correlation with CRP,C3 and C4.5.Receiver operating characteristic（ROC）curve analysis was performed.The results showed that the area under the curve（AUC）when FPR predicted moderate to severe SLE disease activity was 0.671,and the best cut-off value was 0.016.The specificity was 52.5%,the specificity was 82.1%,the area under the curve（AUC）when NLR predicted moderate to severe SLE disease activity was 0.705,the best cut-off value was 3.780,the sensitivity was 55.0%,and the specificity was 82.1%.According to the Delong test,the difference in area under the curve（AUC）between FPR and NLR was not statistically significant（Z=0.368,p=0.713）.Conclusion:1.The FPR and NLR values of SLE patients were significantly higher than those of healthy people.2.The FPR and NLR values of SLE patients in the moderate and severe disease activity group were significantly higher than those in the mild disease activity group.3.FPR and NLR values were positively correlated with disease activity in SLE patients.4.FPR and NLR have certain predictive value for moderate to severe disease activity in SLE patients,and there is no difference in their predictive performance.