Do different cut points for time in range (TIR) correlate with the risk of abnormal carotid intima-media thickness and diabetic retinopathy in patients with type 2 diabetes?
Compared with conventional glucose metrics including HbA1c, continuous glucose monitoring (CGM) can provide more information on diabetes management. Of the multiple metrics generated by CGM, time in range (TIR) is becoming popular for assessing glycemic control in practice and research (1–3). Various target ranges for TIR have been adopted and published, with 3.9–10.0 mmol/L (70–180 mg/dL) often headlined. Since hypoglycemia accounts for a small part of time during a day, TIR is largely a metric of hyperglycemia, thus correlating with vascular complications. Logically, ideal TIR would be matched to minimal complication risk, although pragmatic considerations, namely, what is achievable, may also influence choice of level. For CGM there is a lack of information on the relationship between derived metrics and complications, but normal glucose profiles suggest very tight physiological control, with only brief postprandial excursions >140 mg/dL (7.8 mmol/L) (4,5). To begin to address the issue of the threshold of range above which vascular risk can be detected, we have investigated the associations of multiple prespecified TIR levels with carotid intima-media thickness (CIMT) and diabetic retinopathy (DR) in a large sample of people with type 2 diabetes. Individuals with type 2 diabetes and using a stable glucose-lowering regimen for the previous 3 months were consecutively enrolled from hospitalized patients at …
Lu et al. (2020) studied this question.