Comparison of Real-time CGMS With Intermittently-scanned CGMS in Adolescents and Adults With Type 1 Diabetes Mellitus

Type 1 Diabetes Mellitus (T1DM) is characterized by absolute insulin deficiency. Despite multiple daily insulin injections, glycemic targets are usually not achieved in T1DM patients.Use of continuos glucose monitoring system (CGMS) is associated with improvement in glycemic control and reduction in glycemic variability in T1DM subjects. real-time CGMS (rt-CGMS) and intermittently scanned CGMS (is-CGMS) are the newer CGMS technologies. Previous studies have shown that in T1DM patients rt-CGMS is better than is-CGMS for glycemic control and reducing hypoglycemic episodes in patients with impaired awareness of hypoglycemia, but in patients with normal hypoglycemic awareness this is not well established.

This study is a randomized control clinical cross over study of 6 months duration in patients of T1DM having normal hypoglycemic awareness, with age 15-40 years with a HbA1c range of 8-12%. Following a training period of 2 weeks, 80 participants will be randomized into 3 arms in a ratio of 1:1:2 in rt-CGMS, is-CGMS and SMBG (self monitoring of blood glucose) arms, respectively. For the first two groups Medtronic Guardian Connect Sensor 3 and Abott Freestyle Libre Sensor 2will be applied for 2 weeks, respectively; followed by a crossover at 3 months withapplication of is-CGMS and rt-CGMS, respectively in these groups for a further 2 weeks period. For rest of the study duration these patients in the rt-CGMS and is-CGMS group will be monitored through SMBG. The 3rd SMBG group will act as control. Short term blood glucose control will be assessed by Fructosamine assay in the 2 CGMS groups and long term control by HbA1C.

Type 1 Diabetes Mellitus (T1DM) is characterized by absolute insulin deficiency. Despite multiple daily insulin injections, glycemic targets are usually not achieved in T1DM patients. Use of continuos glucose monitoring system (CGMS) is associated with improvement in glycemic control and reduction in glycemic variability in T1DM subjects. Real-time CGMS (rt-CGMS) and intermittently Scanned CGMS (is-CGMS) are the newer CGMS technologies. Previous studies have shown that in T1DM patients rt-CGMS is better than is-CGMS for glycemic control and reducing hypoglycemic episodes in patients with impaired awareness of hypoglycemia, but in patients with normal hypoglycemic awareness this is not well established.

This study is a randomized control clinical study of 6 months duration in patients of T1DM having normal hypoglycemic awareness, with age 15-40 years with a HbA1c range of 8-12%. Following a training period of 2 weeks, 80 participants will be randomized into 3 arms in a ratio of 1:1: 2 into rt-CGMS, is-CGMS arms and SMBG(Self Monitoring of Blood Glucose) arms respectively. For the rt-CGMS group Medtronic Guardian Connect sensor 3 will be applied for 2 weeks and and for is-CGMS group Free Style Libre will be applied for 2 weeks. The participants randomized into the 3rd group shall do self monitoring of blood glucose(SMBG) throughout the study duration of 6 months. Those participants randomized into rt-CGMS and is-CGMS groups after the end of 2 weeks will also monitor their blood glucose by SMBG till the end of 3 months.The frequency of SMBG for all these groups would be - 4 times a day( premeal blood glucose and one post meal blood glucose on rotational basis) on weekdays and 7 times on Sundays(3 times pre meals, 3 times 2 hrs post meals and once at 3 am). At the end of 3 months participants in the rt-CGMS group will undergo crossover to is-CGMS group and vice versa whereas participants in SMBG group will remain in the same arm till the end of the study(6 months).Short term blood glucose control will be assessed by Fructosamine assay after 2 weeks of CGMS application and long term control by HbA1C at the end of 3 months and 6 months. All glycemic parameters(like Time in Range, Time below Range and Time in Range will be compared in both CGMS groups before and after cross-over and both these arms will be compared with SMBG for all the outcomes.Quality of life will also be assessed in these groups by using QOLID questionnaire.

Eligibility Criteria:
Inclusion Criteria:

1. Adolescents and adults aged 15-40 years with Type-1 Diabetes mellitus defined by any of the following; i. Diabetic Ketoacidosis or ketonemia or ketonuria at diagnosis with insulin dependence for survival since diagnosis OR ii. Insulin dependence for survival since diagnosis and any one of the following autoantibody positivity: GAD-65 or IA-2
2. Patients on Basal bolus regimen (Glargine as basal and lispro /Aspart /Glulisine as bolus);
3. Duration of Diabetes \> 2 years;
4. Insulin dose requirement of at least 0.5U/kg
5. HbA1c 8%-12%;
6. Gold score\<4;
7. No previous experience with rt-CGMS and/or is-CGMS;
8. Euthyroid status;
9. If hypothyroid, then on stable dose of Levothyroxine for last 3 months with normal T4 level;
10. Urine albumin creatinine ratio\<300 mg/g of Creatinine;
11. Those willing to give informed consent prior to enrolment.

Exclusion Criteria:

1. LADA or Secondary Diabetes
2. eGFR\<60ml/min/1.73m2
3. Celiac disease;
4. Hb\<12g/dl for males and \<11g/dl for females;
5. Hypoglycemia unawareness defined by Gold score≥4;
6. HbA1c\>12%;
7. Diabetic Ketoacidosis in the previous 3 months;
8. Severe Non proliferative Diabetic retinopathy/Proliferative Diabetic Retinopathy/Macular edema;
9. Pregnancy;
10. Lactation;
11. Willing to become pregnant during study;
12. Requiring MRI for any existing condition;
13. Any other chronic illness.