An insulin pump which has been on the market four several years now has proven effective in helping patients maintain their blood glucose level, according to a recently completed study. 

The MiniMedTM 670G system has helped type 1 patients maintain their proper level more than 71% of the time, according to results of a study published in the Journal of the Endocrine Society.  The results of the study come almost four years after the FDA approved the pump, during which time more than 180,000 patients have used the device. 

The device, sometimes called an “artificial pancreas,” is the first hybrid closed-loop system to be approved by the FDA. It includes a pump with an insulin infusion catheter and a continuous glucose monitor, which are both worn under the skin. The monitor checks the patient’s glucose every five minutes, sending the results to the pump, which determines how much insulin the patient needs. 

The study collected data from 118,737 patients between March 2017 and July 2019. During that time the data was analyzed to determine the average percentage of overall time spent between 70 mg/dL to 180 mg/dL. According to the results, the mean percentage of overall time spent between 70- 180mg/dL (TIR) was 71.3%. The mean time spent below 54mg/dL was 0.4% and mean time spent at or below 70mg/dL was 1.9%. The mean time spent above 180 mg/dL was 26.8%, and time spent at or above 250 mg/dL was 6.2%.

Among a subset of individuals (n =51,254), the device's Auto Mode was turned OFF for at least 7 days. From OFF mode to ON mode, researchers reported a TIR increase from 60.9% to 69.9%; and a decrease in both mean time below range (TBR;  <54mg/dL ≤ 70mg/dL) and time above range (TAR; >180mg/dL ≥ 250mg/dL). 

The authors noted that in more than 6 million days with the device on Auto Mode, TIR for both pediatric and adult type 1 diabetes patients improved by 9%, compared to when Auto Mode was turned off, “which was comparable to or exceeded the TIR observed in smaller pivotal trials.” 

Researchers also evaluated time spent in range with Auto Mode OFF vs ON  among subgroups of children aged 7 to 13; teens/young adults aged 14 to 21; and adults aged 22 or older. Overall, researchers observed significant improvements across the subgroups: 

• Patients aged 7- 13 years (N=1,417): TIR increased from 48.7% to 61.5%; 

• Patients aged 14-21 years (N=4,194), TIR increased from 51% to 61.5%; and

• Patients aged 22 years or older (N=45,643), TIR increased from 62.2% to 70.9%. 

TBR and TAR decreased across all subgroups except researchers observed small increases of TBR among the youngest subgroup at both the 54 mg/dL and 70mg/dL cutoffs (0.5% to 0.6% and 2% to 2.2%, respectively). 

“Real-world experience does not necessarily live up to the results seen in a clinical trial that recruits highly motivated participants and who are under close supervision,” said principal investigator Robert Vigersky, MD, chief medical officer of Medtronic Diabetes. “Our results demonstrate that the glycemic [blood glucose] control using the MiniMedTM 670G in the real world is excellent and mirrors the results of the small pivotal trials that led to the system’s approval.”

The results of the study were supposed to be presented at the annual meeting of the Endocrine Society which was cancelled due to concerns about COVID-19.