Minimed

Patients were equipped with a CGMS device (Medtronic miniMed, Northridge, CA, USA) and monitored for 72 h. Each CGMS device was calibrated with SMBG four times per day. After the 72 h monitoring period, all recorded data were downloaded onto a personal computer. Glucose profiles and glucose excursion parameters were evaluated with miniMedSolutions software version 3.0 (miniMed, Symar, CA, USA). Parameters analyzed included average, maximum and minimum BG concentrations, and the standard deviation of glucose concentration.

The CGMS (Medtronic MiniMed) was used to monitor interstitial glucose every 5 min during the randomized diet assignments. Women were blinded to CGMS glucose concentrations. Identical glucometers were provided by the investigators (OneTouch, LifeScan Inc., Milpitas, CA); postprandial glucose was measured either 1 or 2 h after meals as per obstetrician preference, with the accepted targets of <140 mg/dL at 1 h and <120 mg/dL at 2 h (1 (link)). Preprandial glucose via glucometer four times daily was also measured for calibration of the CGMS sensor data (correlation between interstitial and meter glucose, r = 0.732; P < 0.0001; n = 840 measures). Women recorded meter glucose and meal start times. CGMS sensors were placed near the lateral iliac crest by an investigator. During the investigation, wireless CGMS equipment became available, but the sensor technology was unchanged. Given it was no longer possible with the wireless device to discern any sensor malfunction, women with the wireless CGMS monitors (n = 4) wore two sensors side-by-side, 1 inch apart in the same adipose tissue bed. The mean of interstitial glucose data from the two sensors was used for analysis in these cases. CGMS glucose variables were extracted and represent the mean over 48 h as we have described in detail previously (20 (link),21 (link)).

Eligible patients who agreed to participate were monitored by a masked CGM (Medtronic MiniMed, Northridge, CA) for a 4-day period without a change in their diabetes regimen. Patients were encouraged to record 4 SMGB (capillary blood) levels each day to calibrate the CGM. They were instructed to follow their usual diet and were advised to abstain from intense and prolonged exercise during the 4-day period.
Glucose variability was expressed as SDBG, overall glucose CV%, MAGE, and MODD. SDBG was defined as the standard deviation of all readings during the CGM. CV% was calculated by the following formula: CV% = SDBG/mean blood glucose (MBG)∗100%. MAGE was defined as the average of absolute values of differences between adjacent peaks and nadirs for all differences >1 standard deviation (SD). MODD was calculated as the mean of the absolute values of the differences between any given glucose value and the value exactly (24 × d) hours later.