COVID-19 pandemic shows CGM ‘supportive tool’ for broad inpatient use
The risk for severe COVID-19 complications is significantly higher for people with diabetes, and data suggest glucose management may play a vital role in disease outcomes.
Yet, careful monitoring of inpatient glucose can prove unsafe for clinicians and nurses, who must repeatedly put themselves at risk to perform routine finger sticks for glucose monitoring. As the cases have risen across the country, more institutions have turned to continuous glucose monitors to allow hospital staffs to monitor patients with hyperglycemia or diabetes in a safe and effective way. Studies documenting the use of inpatient CGM during the pandemic so far are small or ongoing; however, data suggest CGM is effective, even in the ICU setting.
“As an endocrinologist, we can avoid going into the [hospital] room for the routine care of the patient; we can do a lot of things remotely, using video and electronic health records, but I felt there was more we could do to help the team, especially the nurses,” Archana R. Sadhu, MD, FACE, director of the system diabetes program and director of transplant endocrinology at Houston Methodist Hospital and assistant professor of medicine at Weill Cornell Medical College, New York, told Endocrine Today. “These patients [in the ICU] were so insulin resistant, needing hundreds of units per day. Our staff used IV insulin to manage the hyperglycemia, but this requires hourly blood glucose monitoring. That is when the idea came — why can’t we use CGM to reduce blood glucose monitoring? At the same time, FDA allowed for some flexibility in using remote monitoring during the pandemic to protect health care workers. That was our ah-ha moment.”
Carol Levy, MD, clinical director of the Mount Sinai Diabetes Center, said her institution learned many lessons since initiating a pilot program for inpatient CGM use in April, as the pandemic struck New York City. In April, the FDA issued guidance to expand the availability and capability of noninvasive remote monitoring devices during the COVID-19 pandemic, including CGM in the inpatient setting, to improve the ability of health care providers to monitor patients while reducing exposure to the novel coronavirus. At the time, the American Diabetes Association, Insulin for Life and the Diabetes Disaster Response Coalition partnered with Abbott to donate 25,000 CGM sensors to hospitals across the country.
“What has changed since then is there is an increasing level of comfort with CGM use,” Levy told Endocrine Today. “Is it fully adopted across all institutions? Absolutely not. Each institution has had different levels of COVID-19 disease burden for people with diabetes, and different levels of staff training. We are trying to engage our nursing team to become comfortable with utilization, and that is where most sites are with this at this point. We are all coming up with different implementation paths.”
New insulin protocols
In a retrospective study, Sadhu and colleagues analyzed data from 11 adults positive for COVID-19 admitted to the ICU at Houston Methodist with a history of diabetes or hyperglycemia and requiring IV or subcutaneous insulin therapy. Participants received one of two CGM devices — the Dexcom G6 (n = 5) or the Medtronic Guardian Connect (n = 6). Researchers used Bluetooth transmission to connect sensors to an iPad or iPhone outside the patient’s room to display real-time sensor glucose readings. For the first 24 hours, sensor glucose values were documented but not used for clinical management, Sadhu said.
Researchers modified the institution’s usual insulin infusion protocol, from a target range of 140 mg/dL to 180 mg/dL to a broader target of 100 mg/dL to 200 mg/dL, and allowing blood glucose monitoring every 2 hours, Sadhu said.
“I modified the IV protocol to keep glucose in a slightly broader, yet still safe, range than we normally would, so nurses did not have to run in the room every time the glucose fluctuated beyond the narrow 140 mg/dL to 180 mg/dL range,” Sadhu said.
With CGM, blood glucose monitoring could be reduced to every 4 hours if the hourly sensor glucose values were in range and without system alarms or alerts.
To address concerns about accuracy and patient safety, changes in insulin dosing were made using only finger-stick blood glucose measurements. Nurses used log sheets to document hourly sensor glucose, finger-stick blood glucose and administration of known potential sensor interferents.
“Because of the lack of FDA approval for accuracy, I had the added practice where we were not adjusting insulin based on the sensor data,” Sadhu said. “We only used CGM to trend the glucose and then adjust insulin based on intermittent blood glucose readings. We were in a nice position to use the technology to its greatest advantages, and also be cautious about patient safety.”
Primary outcomes were feasibility and accuracy for trending blood glucose values. Secondary outcomes included reliability and nurse acceptance.
Researchers calculated mean absolute relative difference (MARD), Clarke error grid analysis (EGA) and Bland-Altman (B&A) plots for accuracy of paired sensor glucose and finger-stick blood glucose measurements. To determine accuracy, 437 paired sensor glucose and finger-stick blood glucose readings were analyzed.
Fewer finger sticks
Researchers found that both CGM systems were feasible and reliable with good nurse acceptance. For Medtronic, the MARD was 13.1% with 100% of readings in zones A and B on Clarke EGA. For Dexcom, MARD was 11.1% with 98% of readings in zones A and B. B&A plots had a mean bias of –17.76 mg/dL (Medtronic) and –1.94 mg/dL (Dexcom).
“When we added the sensors, I was blown away to see that it was feasible, that we could adapt this to work, because all of this technology is built for outpatient use,” Sadhu said. “I’ll admit, in the beginning, there was a week where I lived in the ICU. There was a learning curve. We had issues like the Wi-Fi not working or needing compatible equipment. Those early obstacles were painstaking, but it was worth it thereafter.”
Researchers also demonstrated a 33.11% reduction in finger-stick blood glucose monitoring when CGM was used.
Proper CGM training is key, according to Levy. At Mount Sinai, someone from the endocrine team is always available to coach the nursing staff or speak by phone if questions come up during shifts, she said.
“At this point, most institutions, sadly, as cases have risen, have gained some level of comfort with these devices, but it is now a matter of getting it out there for the smaller hospitals that are just now experiencing COVID-19 surges or getting overwhelmed,” Levy said. “Almost every institution will have at least 30% or more patients who have diabetes or hyperglycemia.”
There are limitations to the technology, including a need for better integration into inpatient medicine. Staffs will also need to adopt the technology, Levy said. A formal nursing survey in her study was not completed; however, acceptance was high.
Beyond the pandemic, Levy said she hopes that the FDA will consider approving CGM for broad inpatient use in 2021.
“We need data for that; the FDA will not just give a ‘thumbs up,’ nor should they,” Levy said. “We need more formal trials. There are some small ones. I would like to see this utilized beyond the COVID-19 population. Many of us as clinicians will use CGM as a supportive tool for patients who came in already using CGM in the inpatient setting; however, this is not on-label use. It would be so nice to have the opportunity to really maximize the potential of this.”
- FDA. Enforcement policy for noninvasive remote monitoring devices used to support patient monitoring devices used to support patient monitoring during the COVID-19 public health emergency. October 2020. Available at: www.fda.gov/regulatory-information/search-fda-guidance-documents/enforcement-policy-non-invasive-remote-monitoring-devices-used-support-patient-monitoring-during. Accessed Dec. 23, 2020.
- Sadhu AR, et al. J Diabetes Science Technol. 2020; doi:10.1177/1932296820964264.
- For more information:
- Carol Levy, MD, can be reached at firstname.lastname@example.org.
- Archana R. Sadhu, MD, FACE, can be reached at email@example.com.