| Background:Type 1 diabetes mellitus(T1DM)is recognized as the destruction of the β-cells and absolute insulin deficiency.Recent studies have shown that T1 DM is also accompanied by insulin resistance,and insulin resistance is associated with the diabetes complications.Therefore,it is of great significance to explore the prevalence and risk factors of insulin resistance in T1 DM patients for guiding clinical treatment and reducing the risk of complications.However,few studies have explored the clinical characteristics and influencing factors of insulin resistance in Chinese patients with T1 DM around the duration of diabetes.In addition,T1 DM is a chronic metabolic disease that depends on exogenous insulin treatment,but the effect of insulin dose and glucose control on insulin resistance in T1 DM patients remains unclear.Objective:(1)A cross-sectional study was conducted to explore the clinical characteristics,influencing factors and trend of insulin resistance with the duration of T1 DM.(2)A cohort follow-up study was conducted to explore the change characteristics of insulin resistance in patients with T1 DM along with the duration of diabetes.Especially,the effects of cumulative insulin dose and cumulative Hb A1 c on insulin resistance were investigated.Methods:(1)In the first part of this study,a total of 600 T1 DM patients with age ≥10 years and diabetes duration ≥ 6 months were enrolled in the department of Endocrinology,Second Xiangya Hospital,Central South University.Overweight/obesity/central obesity,hypertension,dyslipidemia,metabolic syndrome,metabolic disorder and estimated glucose disposal rate(e GDR)were used to comprehensively reflect insulin resistance.This study investigated the influencing factors of insulin resistance from clinical characteristics,serum marker with therapeutic potential-proprotein convertase subtilisin/ kexin type 9(PCSK9),and carotid intima-media thickness(CIMT),which reflects cardiovascular risk.(2)The second part of this study was a follow-up study of 223 T1 DM with age ≥10 years,baseline diabetes duration ≤6 months and median follow-up of 2 years.Age,duration of T1 D,insulin dose,height,weight,waist circumference,hip circumference,and blood pressure were recorded at baseline and at each follow-up.At the same time,hemoglobin A1c(HbA1c),high density lipoprotein cholesterol(HDL-C),triglyceride(TG)and other laboratory indicators were detected.The new-onset T1 DM cohort was used to further verify the trend of insulin resistance with the duration of T1 D,and to explore the effects of cumulative insulin dose and cumulative Hb A1 c on insulin resistance.Results:(1)The prevalence of overweight/obesity/central obesity,hypertension,abnormal TG/HDL-C,metabolic syndrome and ≥1metabolic index disorders were 15.4%,26.5%,17.6%,10.9% and 43.7%,respectively.The median e GDR was 8.9(7.3-10.2)mg/kg/min.(2)The duration of diabetes is an important factor of the insulin resistance.Insulin resistance shows a trend of gradual increase in the first10 years after the onset of diabetes,and a relatively stable state after 10 years.The risk of insulin resistance was significantly higher in patients with long-duration T1 DM than in patients with short-duration T1 DM.In addition,gender,age,the history of smoking and drinking were also associated with insulin resistance.In T1 DM patients with poor glycemic control,serum PCSK9 level is closely related to insulin resistance.Besides,insulin resistance was associated with CIMT.(3)The follow-up study showed that the insulin resistance of patients with T1 DM increased slowly in the first 4 years after the onset of diabetes,and the overall status was relatively stable.Mean cumulative insulin dose and mean cumulative Hb A1 c were closely correlated with insulin resistance.There was an interaction between mean cumulative insulin dose and Hb A1 c on overweight/obesity/central obesity and the e GDR.Specifically,the risk of overweight/obesity/central obesity was higher in patients with average cumulative insulin dose ≥0.5u/kg/day than in those with average cumulative insulin dose < 0.5 U /kg/day under poor glycemic control(mean cumulative HbA1c≥7.0%).However,the risk of abnormal e GDR was higher in patients with average cumulative insulin dose ≥0.5u/kg/day than in those with average cumulative insulin dose < 0.5U /kg/day under good glycemic control(mean cumulative HbA1c<7.0%).Conclusions:(1)About 40% of T1 DM patients are accompanied by the metabolic disorders related to insulin resistance,and the duration of diabetes is an important factor of insulin resistance.Besides,gender,age,the history of the smoking and drinking,serum PCSK9 level and CIMT were correlated with insulin resistance.(2)The insulin resistance varies with the duration of the T1 DM.The mean cumulative insulin dose and mean cumulative Hb A1 c influence the occurrence of insulin resistance.There was an interaction between mean cumulative insulin dose and mean cumulative Hb A1 c for overweight/obesity/central obesity and abnormal e GDR. |
