The value of Continuous Glucose Monitoring and Self-Monitoring of Blood Glucose in patients with Gestational Diabetes Mellitus during Ramadan fasting

Introduction: In order to achieve the recommended glycemic control, women with Gestational Diabetes Mellitus (GDM) are instructed to self-monitor blood glucose (SMBG) regularly. The purpose of this study was to evaluate glucose readings provided by Continuous Glucose Monitoring (CGM) and SMBG in GDM patients during Ramadan fasting. Methods: This is a prospective observational study that recruited GDM patients treated with diet ± metformin were enrolled. They agreed to wear the iPro®2 Professional CGM device and to do SMBG by glucose reading meters, during fasting and after meals. We evaluated the rates of hypoglycemia and hyperglycemia in each approach. The frequency and timing of SMBG was investigated. Results: Twenty-five patients were recruited. A total of 36,628 readings by CGM device and 408 readings using glucose meters and were captured. Average glucose level was 103 ± 8 mg/dl (5.7 ± 0.4 mmol/l) and 113 ± 14 mg/d (6.28 ± 0.8 mmol/L) on CGM and glucose meters respectively. The rate of hyperglycemia was 5.65% and 14.2% and hypoglycemia was 4.35% and 1.5% using CGM and glucose meters respectively. While all hypoglycemic episodes occurred between 16:00–19:00 in both approaches, only 38 readings (9%) of SMBG readings were done in that time frame. Conclusion: Although the frequency of SMBG using glucose meters for women with GDM and fasting Ramadan was acceptable, the timing was not. CGM detected more hypoglycemia and less hyperglycemia than SMBG. Relying on Intermittent SMBG in the management of GDM patients during Ramadan fasting might be misleading.