Ultrasound Detection Of Lipohypertrophy Characterization And Its Effect On Glycemic Variability In Diabetes With Insulin Injection

Objective:The purpose of this study was to assess the lipohypertrophy（LH）in diabetes with insulin subcutaneous injection by ultrasound examination,and further to analyze the related influencing factors of LH and the possible effects of LH on glycemic variability.Method:Through a cross-sectional study,a total of 120 diabetes with insulin subcutaneous injection who were present in our hospital from April 2019 to December 2019.A questionnaire was used to register the general information of patients（including name,gender,age,duration of diabetes,Hemoglobin A1c（Hb A1c）within 3 months,daily total amount of insulin injection and frequency of insulin injection,needle length needle reuse frequency,rotated the injection site or not）,and measured the height,weight,waist circumference and Body mass index（BMI）.LH assessment was performed on the abdomen by ultrasound and clinical examination for all patients.Patients were selected to inject the same amount of insulin into Lipohypertrophy tissue（LHT）and Normal adipose tissue（NAT）for two consecutive days a week,and a portable blood glucose meter was used to measure finger blood glucose（including before breakfast,2h after breakfast,before lunch,2h after lunch,before dinner,2h after dinner,10pm）.Self monitoring of blood glucose（SMBG）methods^[1][including Largest amplitude of glycemic excursion（LAGE）,Mean blood glucose（MBG）,Standard deviation of blood glucose（SDBG）,Postprandial glucose excursion（PPBG）]were used to assessthe effect of LH on glycemic variability.Resluts:1.General information:120 diabetes with insulin injection were included in this study,including 108 patients with Type 2 diabetes mellitus（T2DM）and 12 patients with Type 1 diabetes mellitus（T1DM）,70 males and 50 females,with an average age of 59.2±11.43 years,a median insulin injection period of 5.50（5.0）years,an average total daily insulin injection of 36.08±19.05 units,and an average Hb A1c of 9.45±1.85%.38.0%of patients used 4 mm injection needles,39.0%of patients used 6mm injection needles,and 23.0%of patients used 8mm injection needles.2.Incidence of LH in diabetes with abdominal subcutaneous insulin injection:120dibetes with abdominal subcutaneous insulin injection were examined by physical examination and ultrasound examination to evaluate LH.56（46.6%）patients found LH by physical examination,83（69.1%）patients found LH by ultrasound examination,27（22.5%）patients found LH only by ultrasound examination.Compared with ultrasound examination,the ratio of missed diagnosis of LH in patients with physical examination was 32.6%.3.Comparion of LHT found by ultrasound and physical examination:144 and 67LHT were respectively found by ultrasound and physical examination.Compared with ultrasound examination,the ratio of missed diagnosis of LH in patients with physical examination was 53.5%.When the vertical lengths of LHT were<5mm,5～10mm,and>10mm,compared with ultrasound examination,the ratio of missed diagnosis of LH in patients with physical examination were 94.2%,32.9%,and 10.0%.When the horizontal width of the lesion area was<5mm,5～10mm,>10mm,the ratio of missed diagnosis of LH in patients with physical examination were 95.2%,71.1%,and 4.2%.When the area of the lesion area was<30mm²,30～60mm²,>60mm²,compared with the ultrasound examination,the ratio of missed diagnosis of LH in patients with physical examination were 95.9%,74.4%,3.5%.LHT vertical length,horizontal width,and hyperplasia area were closely related to the missed diagnosis rate of physical examination（P<0.05）.4.Comparison of the thickness of subcutaneous fat layer in diabetes with LH and without LH:The thickness of subcutaneous fat layer in the umbilicus,subumbilical,left and right umbilical cords of 5cm and 10cm was significantly increased in diabetes with LH compared with diabetes without LH,and the difference was statistically significant（P<0.05）.5.Ratio of different subcutaneous fat thickness in diabetes with LH and without LH:According to the current clinical application of insulin injection needle length,the subcutaneous fat thickness of patients were divided into three levels:<6mm,6～8mm,and>8mm.Compared with patients without LH,The ratio of subcutaneous fat thickness<6mm in the left,right,and lower 5cm of the umbilicus were higher in diabetes with LH（P<0.05）,while,the ratio of subcutaneous fat thickness>8mm in the left,right 5cm of the umbilicus,and 5cm above the umbilicus were higher in diabetes without LH.（P<0.05）.6.Influence factor of LH:The incidence of LH in patients with insulin injection duration<5 years,5～10 years,>10 years were 48.1%,78.4%,96.6%.The incidence of LH in patients with needle reuse frequency<4 times,4～8 times,>8 times were 53.1%,78.9%,and 90.9%,The incidences of LH in patients roated the injection site and unroated the injection site were 60.6%and 79.6%.The incidence of LH in patients with1,2,4 insulin injection were 29.0%,61.5%,and 92.1%,and the differences were statistically significant（P<0.05）.Incorporating the above statistically significant influencing factors into the analysis of logsitc regression model,the results showed that insulin injection duration（OR=1.385,95%CI=1.165～1.647）and daily insulin injection times（OR=2.994,95%CI=1.905～4.704）were the risk factor of LH,and roated the injection site（OR=0.323,95%CI=0.103～0.715）was the protective factor of LH.7.Influence factor of LHT planar area:The planar area of LHT in patients with insulin injection duration<5 years,5～10 years,>10 years were 79.93±51.63 mm²,118.04±73.57 mm²,157.80±73.67 mm².The planar area of LHT in patients with needle reuse frequency<4 times,4～8 times,>8 times were 83.22±74.46 mm²,116.55±62.94 mm²,162.29±43.86 mm².The planar area of LHT in patients roated the injection site and unroated the injection site were 84.34±53.42 mm²,134.68±83.19mm².The planar area of LHT in patients used 4mm,6mm,8mm injection needles were74.81±45.06 mm²,111.99±74.73 mm²,165.85±72.96 mm².The differences were statistically significant（P<0.05）.Incorporating the above statistically significant influencing factors into the analysis of multivariate linear regression model analysis.the results showed that insulin injection duration（B=0.209,P=0.048）,roated the injection site or not（B=0.194,P=0.049）,needle reuse frequency（B=0.216,P=0.042）,the length of needle（B=0.230,P=0.026）were risk factors for planar area of LHT.8.The effect of LH on blood glucose:LHT and NAT were injected with the same amount of insulin in diabetes with LH,the blood glucose of 2h after breakfast were10.17±1.88 mmol/L and 11.87±1.50 mmol/L,the blood glucose of 2h after lunch were 10.66±1.82 mmol/L and12.15±1.87 mmol/L,and the blood glucose of 2h after dinner were 10.36±1.70 mmol/L and 11.76±1.81 mmol/L,the difference between two groups were statistically significant（P<0.05）.while blood glucose before breakfast were8.30±1.47 mmol/Land 8.37±1.17 mmol/L,the blood glucose before lunch were 8.75±1.45 mmol/L and 8.73±1.40 mmol/L,the blood glucose before dinner was 8.42±1.74 mmol/L and 8.55±1.38 mmol/L,blood glucose at 10 PM were 9.37±1.27 mmol/L and 9.51±1.84 mmol/L,the difference between two groups were not statistical significance（P>0.05）.9.The effect of LH on glycemic variability:LHT and NAT were injected with the same amount of insulin in diabetes with LH,the glycemic variability indexes LAGE were 5.70±1.74 mmol/L and 4.21±1.29 mmol/L,MBG were 10.13±0.92 mmol/L and9.43±1.16 mmol/L,SDBG were 1.96±0.58 mmol/L and 1.39±0.39 mmol/L and PPBG were 3.44±1.24 mmol/L and 1.99±0.64 mmol/L.The LHT group was significantly higher than the NAT group,the difference was statistically significant（P﹤0.05）Conclusion:1.lipohypertrophy have special ultrasound signatures,such as hyperechoic or hypoechoic（interstitial edema）nodules,distortion of surrounding connective tissue,and lack of vascularized echo.2.Ultrasound examination can find more lipohypertrophy tissue than physical examination,also can accurate measure the thickness of subcutaneous fat,which can guide patients to choose the correct injection site.3.Insulin injection duration,needle reuse frequency,roated the injection site or not,the length of needle,daily insulin injection times were main influence factors of LH.4.Lipohypertrophy can affect patients’blood glucose,and the blood glucose of 2h after meal and glycemic variability can inceased when inject at lipohypertrophy tissue.Educating patients to avoid injection in lipohypertrophy tissue can enhance blood glucose control.