TIGHT: Inpatient CGM use did not improve glycemic control
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Key takeaways:
- Mean glucose concentrations were similar for hospitalized patients using real-time CGM vs. standard of care.
- Patients with HbA1c greater than 9% had harder to control blood glucose regardless of treatment group.
ORLANDO — Adding continuous glucose monitoring to hospital standard of care does not appear to improve glycemic control for adults with type 2 diabetes, according to results of the TIGHT study.
“Prior research of intensive glucose management in the inpatient is limited. There were several papers during the COVID period, but they were primarily addressing safety of interaction between staff and patients, rather than impact of glycemic level on the outcome of patients’ hospitalization,” Boris Draznin, MD, PhD, visiting clinical professor of medicine at the University of Colorado School of Medicine, said during a presentation at the American Diabetes Association Scientific Sessions. “Given a variety of difficulties in inpatient settings, primarily related to insulin injection, timing of food, variability of food, we did an appropriate outcome trial using CGM to determine if use of CGM in non-ICU settings is effective, feasible and safe.”
The TIGHT study is an investigator-initiated, multicenter, randomized, parallel-group trial with 110 adults with type 2 diabetes or an HbA1c of more than 7% from six academic institutions with glycemic management teams. Participants had at least one blood glucose concentration of more than 180 mg/dL since hospital admission, insulin already initiated or planned for initiation, an expected non-ICU hospital stay of more than 3 days and at least 12 hours of CGM data after the first 24 hours after randomization. Researchers randomly assigned 110 patients (mean age, 61 years) to the intensive target group (n = 60; 57% white), where the glucose management team monitored glucose using real-time CGM with a target glucose concentration of 90 mg/dL to 130 mg/dL, or the standard target group (n = 50; 64% white), in which the glucose management team followed hospital’s usual practice using insulin with a target of 140 mg/dL to 180 mg/dL and patients wore a masked CGM sensor.
Dexcom G6 CGMs were used before switching to G6 Pro after identifying bias. Patients were switched to G7 CGMs when it became available.
Primary outcome was mean glucose level and percentage of time less than 54 mg/dL.
Overall, patient demographics, diabetes-related characteristics and HbA1c levels were similar between groups. The average HbA1c was 8.9%. The most common reason for hospital admission was infection for 40% of patients in the intensive group and 44% in the standard group.
Researchers observed no difference in mean glucose — 170 mg/dL in the intensive group and 175 mg/dL in the standard group. Seven percent of patients in the intensive group and 6% in the standard group had mean glucose of 90 mg/dL to 130 mg/dL. Glucose of 140 mg/dL to 180 mg/dL and glucose greater than 180 mg/dL was observed among 48% and 33% of patients in the intensive group and 32% and 52% of patients in the standard group, respectively.
Times in range 70 mg/dL to 180 mg/dL, 70 mg/dL to 140 mg/dL, greater than 180 mg/dL and greater than 250 mg/dL were not significant different between the intensive and standard groups. Hypoglycemia rates were low with 0.2% in the intensive group and 0.4% in the standard group.
HbA1c levels were categorized as less than 7.5%, 7.5% to 9% and greater than 9%. Participants in the intensive group with an HbA1c less than 7.5% and 7.5% to 9% had a mean glucose of 155 mg/dL and 166 mg/dL, respectively, which was lower than 170 mg/dL and 182 mg/dL observed for the standard group. According to the researchers, patients with an HbA1c greater than 9% had harder to control blood glucose regardless of treatment group.
Researchers observed no significant difference in blood glucose concentrations when patients were switched from the G6 to the G7 CGMs.
“This is something that we have to keep in mind as clinicians,” said Guillermo Umpierrez, MD, professor of medicine in the division of endocrinology at Emory University School of Medicine. “In those patients admitted with HbA1c less than 9%, you have a beneficial effect of the CGM and intensive glycemic control.”
Perspective
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The TIGHT trial, presented at the recent American Diabetes Association Scientific Sessions, provides key insights into inpatient glycemic management using continuous glucose monitoring. This multicenter, randomized study involved 110 adults with type 2 diabetes, comparing an intensive target group (target glucose of 90 mg/dL to 130 mg/dL) using real-time CGM to a standard target group (target glucose of 140 mg/dL to 180 mg/dL) with masked CGM. Results indicated no significant difference in mean glucose levels between the intensive (mean glucose, 170 mg/dL) and standard groups (mean glucose, 175 mg/dL), with low hypoglycemia rates in both.
Patients with HbA1c levels above 9% faced greater challenges in controlling blood glucose, regardless of the treatment group. This suggests the need for closer attention to glycemic management in these patients and underscores the importance of checking HbA1c upon admission. Despite CGM's success in outpatient care, its benefits in hospitals are currently limited by factors such as staff training and complexity of integrating CGM data into workflows, yet it has definite potential.
The greatest need for inpatient CGM may be in small community hospitals, not large academic centers. These hospitals often lack specialized diabetes teams and confidence in CGM placement and interpretation. A similar trial in a community hospital setting, comparing CGM use to standard diabetes management by non-specialized glycemic management teams, would be interesting.
The full results of the trial have yet to be published. Further research is necessary to optimize CGM use in diverse hospital settings to fully harness its potential.
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Draznin B, et al. Results from a randomized trial of intensive glucose management using CGM versus usual care in hospitalized adults with type 2 diabetes. Presented at: American Diabetes Association Scientific Sessions; June 21-24, 2024; Orlando.
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