Worsening Time in Glucose Target Range Linked to Microvascular Complications in Type 1 Diabetes: Study
A real-world study of 246 adults with type 1 diabetes has revealed that worsening time in range (TIR), the proportion of time glucose levels remain within the target range, was associated with a higher 5-year incidence of microvascular complications. The findings highlight the potential importance of maintaining stable glucose control over time to reduce diabetes-related complications. The study was published in The Journal of Clinical Endocrinology & Metabolism by Amber S. and colleagues.
A prospective 5-year cohort study conducted in a tertiary referral center sought to determine whether CGM parameters were accurate predictors of tissue injury in the long term. The cohort comprised 246 adults who had been diagnosed with type 1 diabetes (median age 40 years [IQR, 28–53], median diabetes duration 24 years [IQR, 13–33]). Longitudinal CGM profiling was conducted on these patients without any experimental intervention.
The primary outcome of the study was the microvascular composite endpoint that included diabetic nephropathy (persistent albuminuria ≥ 20 µg/min, eGFR < 60 mL/min/1.73 m², or RAAS inhibitors for albuminuria), severe retinopathy (proliferative retinopathy, maculopathy, or blindness), and peripheral neuropathy (monofilament test score < 6/6 or abnormal nerve conduction study).
Key findings:
- The longitudinal assessment of 246 participants with T1D over the 5-year follow-up revealed specific metrics on quantifiable glucometric parameters and correlations with microvascular risk.
- Cohort average HbA1c dropped from 7.6% (59 mmol/mol) to 7.2% (55 mmol/mol), while TIR grew from 50 ± 14% to 61 ± 15%.
- A group of subjects showing a reduction of 10% or more in TIR had a substantially higher prevalence of microvascular complications during 5 years of observation (33.3%) than the patients with unchanged TIR (7.9%) and an increase of 10% or more (15.0%), p = 0.011.
- Multivariate regression analysis found that ΔTIR maintained its independent relation to microvascular complications after adjustment for age, baseline TIR, BMI, and systolic blood pressure.
- Predictive models using CGM glucometrics together with age of a patient exhibited decent discriminating properties with area under the curve (AUC) from 0.757 to 0.787.
In summary, CGM-derived glucometrics have been shown to be significantly linked with the 5-year risk of developing microvascular complications in patients with type 1 diabetes mellitus. The results from this research indicate that ΔTIR provides meaningful predictive information beyond the commonly used HbA1c measurement; however, more work is needed before clinical application.
Reference:
Amber Sabbe, Niels Bochanen, Annelies Van den Broucke, Katarina Mihaljčić, Axelle Bigaré, Kristof Van Dessel, Jason Bouziotis, Kristien Ledeganck, Eveline Dirinck, Nancy Bolsens, Jolien De Meulemeester, Pieter Gillard, Christophe De Block, Association between worsening time in range and microvascular complications in type 1 diabetes: real-world 5-year study, The Journal of Clinical Endocrinology & Metabolism, 2026;, dgag380, https://doi.org/10.1210/clinem/dgag380
