Lockdown Bonus: Tighter Glucose Control in Type 1 Diabetes

Miriam E. Tucker

May 29, 2020

Editor's note: The Spanish study cited in this story has been retracted from Diabetes Technology & Therapeutics because the authors did not seek institutional review board approval for their research, as reported here.

In the search for silver linings from the COVID-19 pandemic, this is at least a short-term one: adults with type 1 diabetes confined at home during quarantine were better able to keep their blood glucose levels in target range, according to two new studies.

Both studies, one from Italy and one from Spain, were of adults with type 1 diabetes using continuous glucose monitoring (CGM) or flash glucose monitoring devices, and both showed increased time with blood glucose levels in the 70-180 mg/dL (3.9-10 mmol/L) range, with no rise in hypoglycemia during the first few weeks after quarantine began in the respective countries, compared with prior weeks.  

"Our observation...is reassuring and suggests that a slowing down of routine activities can have favorable effects on glucose control in the short term," say Benedetta Maria Bonora, Metabolic Disease Unit, University of Padova, Italy, and colleagues, in their article published online May 11 in Diabetes Therapy.

"We speculate that such an improvement occurred because patients had more time to concentrate on diabetes control and had a more regular lifestyle, including the timing and composition of meals, while not being exposed to workplace stress," they note.

In addition, they speculate, "the knowledge that diabetes worsens the outcomes of COVID-19 may have improved patients' awareness and compliance to diabetes management."

Large Burden: Glucose Control Depends on Individual Circumstances

Asked to comment, Steven J. Russell, MD, PhD, told Medscape Medical News that the findings align with his experience during the pandemic.

"Most of my patients use CGM and we have reviewed their recent results during telemedicine visits. I didn't compare to immediately pre-lockdown, but rather to the download at their last visit 3-4 months before, but in nearly all cases their glycemic control had improved or was about the same."

Russell, of the Diabetes Research Center, Massachusetts General Hospital, Boston, added: "The speculations...that the people with diabetes were able to devote more time to diabetes management, were able to have more regularity to their schedules, and may have had less stress associated with their commutes and work, seem highly plausible to me."

"This proposed explanation is consistent with the observation that diabetes management imposes a very large burden on people with diabetes, one that can be hard to make time to manage and one that competes with other demands on their time," he said.

However, the findings may be somewhat different in children and adolescents depending on their family situation, Mary Pat Gallagher, MD, of the Pediatric Diabetes Center, Hassenfeld Children's Hospital at NYU Langone Health, New York City, told Medscape Medical News.

"Kids whose parents are single or are essential workers, or both, have less supervision, whereas kids who went to the mountains with their two lawyer parents who work from home are getting home-cooked meals three times a day. It's a very striking difference how this is affecting people of different means," she said.

A1c Improved in Most Patients, as Did Time in Range, in Spain

The Spanish study included 147 adults with type 1 diabetes, all on multiple daily injections and using CGM (Dexcom or Eversense) or flash glucose monitoring (FreeStyle Libre, Abbott).

All patients had their data downloaded via the respective web-based software (Clarity, Eversense Pro, or LibreView), explain Pilar Isabel Beato-Víbora, MD, PhD, of the Endocrinology and Nutrition Department, Badajoz University Hospital, Spain and colleagues, in their article published online May 12 in Diabetes Technology & Therapeutics.

Data were compared from the 2 weeks prior to the state of emergency declaration in Spain (March 1-14, 2020) to those 2-5 weeks after lockdown (April 4-17, 2020).

The proportions of patients experiencing a change in A1c of 0.4% or more were 37% (n = 55) with an improvement and 16% (n = 23) with a deterioration.

For time spent in a blood glucose range of 70-180 mg/dL, 3% (n = 5) of patients had no change, 62% (n = 91) had an improvement of more than 1%, and 35% (n = 51) had a deterioration of more than 1%. 

Findings were similar for the CGM and flash monitoring systems, except that time spent below 70 mg/dL increased slightly with users of the latter monitors, from 4.1% to 4.4% (P = .022). Time less than 54 mg/dL remained unchanged.

In Italy, Improvement Seen Only in Those Who Actually Stayed Home

The Italian government's lockdown began in late February 2020, with stricter measures imposed in March.

The study by Bonora and colleagues involved 33 adults with type 1 diabetes who were all using FreeStyle Libre monitors and sharing their sensor data with the diabetes outpatient clinic via LibreView.

Of the 33 patients, 20 stayed home during lockdown and 13 continued to go out as essential workers. None were known to have been infected with the SARS-CoV-2 virus, nor to have had close contact with infected people.

Comparing the week before to the first week after lockdown among those who stayed home, the average glucose reading had decreased from 177.7 to 161.0 mg/dL (P = .005). The standard deviation of sensor readings decreased from 58.9 to 53.2 mg/dL (P = .004).

Time in hypoglycemia did not significantly change, whereas time in range increased from 54.4% to 65.2% (P = .01) and time in hyperglycemia decreased from 42.3% to 31.6% (P = .016).

On the other hand, no differences were seen in any measures of glucose control from before to after the start of lockdown among the patients who continued to work.

Looking Ahead

Asked to comment on the implications of these findings now that lockdowns are beginning to be lifted in many areas, Russell said: "This is one of the reasons why devices that partially or fully automate glucose management — artificial pancreas or bionic pancreas devices — have so much potential to improve glycemic control and quality of life in people with diabetes."

"They allow the relentless task of evaluating glucose information and making decisions about insulin dosing to be offloaded to computer algorithms, and allow the person with diabetes to spend more of their time and energy on other things."

Pediatric endocrinologist Gallagher said she is currently involved in a T1D Exchange population health surveillance study of individuals in the United States with type 1 diabetes suspected or confirmed to have contracted COVID-19.

First publication of the results are expected in early June, she said.

Bonora, Beato-Víbora, and Gallagher have reported no relevant financial relationships. Russell has reported being on advisory panels for Companion Medical and Unomedical, is a consultant for Flexion Therapeutics, and receives research support from Beta Bionics, MITRE Corporation, Novo Nordisk, and Zealand Pharma. He also has other relationships with ADOCIA, Ascensia Diabetes Care, Lilly Diabetes, Roche Diabetes Care, and Senseonics.

Diabetes Ther. Published online May 11, 2020. Full text

Diabetes Technol Ther. Published online May 12, 2020. Full text

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