| Background and Purpose:Diabetic Retinopathy(DR)is a common microvascular complication of diabetes mellitus(DM).With the increasing incidence of diabetes mellitus worldwide,DR has become the main cause of visual impairment and blindness in working-age people.Especially among adult type-two diabetic patients,20-40%of patients have retinopathy,and 8%of patients lose their sight.In the early stages of DM,DR is usually asymptomatic.If left untreated,DR can seriously impair vision and even be associated with a higher risk of systemic vascular complications,placing an enormous burden on individuals,families and society.Therefore,timely monitoring and early diagnosis are of great significance to the prevention and treatment of DR.Cystatin C(Cys-C)is a member of the superfamily of cystine protease inhibitors produced by the karyocyte of the body.It is a basic non-glycosylated protein,mainly distributed in human extracellular fluid,and the content of Cys-C is high in cerebrospinal fluid.It has been found that Cys-C is expressed in the vitreous body and retinal cells of rats.In recent years,a large number of studies have found that serum Cys-C participates in the inflammatory response of the body by regulating the biological activity of cysteine protease,and then affecting the migration and phagocytosis of neutrophils.It is suggested that the level of serum Cys-C may be involved in the pathophysiological changes of diabetic microangiopathy through this pathway.Among them,some scholars have shown that serum Cys-C can be used as a risk factor to predict type 2 diabetic retinopathy,with the increase of serum Cys-C level,the severity of DR is more serious.Retinal vessels,as the only visible terminal vessels in the human body,can be analyzed non-invasivly and intuitively.With the development of computer software,the retinopathy can be observed by color fundus photographs,and the retinal vascular diameter can be evaluated quantitatively and standardized in order to determine the degree of DR.Although it has been shown that serum Cys-C is closely related to the occurrence and development of diabetic microangiopathy,the effect of serum Cys-C on microvascular diameter is still uncertain.Therefore,in our research,we try to figure out following problems.Analysis of risk factors of serum Cys-C level in type 2 diabetes mellitus.Comprehend the relationship between the Cys-C levels and type 2 diabetes retinal vessel diameter,to make explicit the change of type 2 diabetes retinal arteriovenous diameter with the change of Cys-C,then to find out the level of serum Cys-C for predicting abnormal retinal arteriovenous ratioMaterials:A total of 110 patients with type 2 diabetes mellitus(T2DM)from NanFang Hospital were selected between July 2014 and July 2018.The selection criteria are based on the 1999 World Health Organization(WHO)Diagnostic Basis and Classification criteria for diabetes mellitus.Patients with type 1 diabetes mellitus or a specific type of diabetes mellitus,acute complications of diabetes mellitus,fundus diseases caused by orbital tumors,secondary nephropathy caused by trauma or other pathogeny,pyelonephritis and kidney stones are excluded.Methods:The data of patients were collected including:sex,age,duration of diabetes mellitus,body mass index,smoking,drinking,coronary heart disease,hypertension,stroke,diabetic nephropathy and diabetic retinopathy,and test indicators,such as glycosylated hemoglobin(HbAlc),blood lipid levels,renal function indicators,and C-reactive protein,were measured by the laboratory of our hospital.All subjects underwent fundus photography,then we used ImageJ software to measure the retina arteriovenous diameter.The data was showed as X±S or percentages.All data were analyzed by SPSS22.0 statistical software,the main tests are as following:Spearman or pearson test,Binary Logistic analysis or Ordered multi-classification Logistic analysis and ROC curve analysis.The test level is ? = 0.05,P<0.05 meant that difference was statistically significant.Results:1.There are significant differences in age,duration of diabetes,HbA1c and renal function between different groups.The levels of Cys-C are statistically significant in patients with T2DM complicated with hypertension,Diabetic Nephropathy and Diabetic Retinopathy(DR).The level of serum Cys-C in different DR stages was statistically different,with the progression of retinopathy in diabetic patients,the level of serum Cys-C increased(P<0.05).Multivariate Logistic analysis shows that uric acid(UA)and estimated glomerular filtration rate(eGFR)are the risk factors for Cys-C abnormalities,statistically significant.2.There is a positive correlation between retinal venular equivalent(RVE)and Cys-C and a negative correlation between arteriovenous ratio(AVR)and Cys-C(p<0.05).Multiple classification Logistic regression analysis shows that smoking,drinking,coronary heart disease and Cys-C abnormality(Cys-C>1.03mg/L)are the risk factors of increased RVE,P<0.05.3.With the severity of DR,the level of serum Cys-C increased and AVR gradually decreased(p<0.05).With the increase of Cys-C level,RVE becomes larger and AVR becomes smaller,with statistical difference.But there was no significant difference in retinal arteriolar equivalent(RAE)among different serum Cys-C groups.4.ROC analysis of serum Cys-C in predicting AVR,AUC=0.615,P<0.05,95%Cl is 0.508-0.721,shows that the serum Cys-C cutoff value is 1.105mg/L,Yoden index is 0.26,sensitivity is 67.3%,and specificity is 58.2%.Conclusion:1,The level of serum Cys-C in type 2 diabetes patients with hypertension,diabetic nephropathy and diabetic retinopathy was significantly increased.Serum Cys-C level is affected by eGFR.2.Smoking,drinking,coronary heart disease and abnormal serum Cys-C level were the risk factors for the increase of RVE in patients with T2DM.With the increase of serum Cys-C level,the degree of DR is more serious,RVE increases and AVR decreases,but serum Cys-C level has no significant correlation with RAE.3.When serum Cys-C?1.105mg/L,AVR<2/3 can be predicted. |
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