Using Time in Tight Glucose Range as a Health-Promoting Strategy in Preschoolers With Type 1 Diabetes
ARTICLE HIGHLIGHTS
• Why did we undertake this study?
Children who develop diabetes in their first years of life risk being exposed to many decades of hyperglycemia, hence having a high risk of early complications and premature death.
• What is the specific question(s) we wanted to answer?
The purpose of this review is to share and discuss knowledge and experiences of working with time in tight range (TITR) as a health-promoting strategy in preschoolers with type 1 diabetes.
• What did we find?
Data show that 50% TITR is achievable in preschoolers with type 1 diabetes with modern diabetes care.
• What are the implications of our findings?
For children with access to an experienced health care team and diabetes technologies, a currently realistic target can be at least half of the time in normoglycemic range.
The purpose of insulin treatment in children with type 1 diabetes (T1D) is to promote health and quality of life (QOL) in the short- and long-term. To achieve sustainable health and freedom from complications, hyperglycemia needs to be avoided (1,2). Children who develop diabetes in their first years of life risk exposure to many decades of hyperglycemia, hence having a high risk of early complications and premature death (3). An additional age-dependent risk is that dysglycemia, especially hyperglycemia, negatively affects the developing brain (4). In estimating complication risk for current preschoolers with T1D, a 70-year perspective needs to be kept in mind—not only risk in the relatively short 30-year period, as has previ- ously been reported as long-term follow-up (2,5).
In evaluating the outcome of insulin treatment at an individual and group level, cutoff thresholds for glucose values are needed. All of these targets are somewhat arbitrarily chosen. The choice of glucose cutoffs has many implications. Group-level recommendations are the basis for education of people with diabetes (PwD) and diabetes team staff and can also be used in designing algorithms for auto- mated insulin delivery (AID) and to form a basis for reporting in quality registers. An individual treatment target is a matter of agreement between the diabetes team and PwD.
In Sweden, over the past two decades, many pediatric diabetes teams set glycemic targets to 70–140 mg/dL (3.9–7.8 mmol/L). In everyday conversations with families this was referred to as 4–8 mmol/L. The pur- pose of this was to maximize normoglycemia. This work was initiated prior to continuous glucose monitoring (CGM) access.
When CGM became available, there was no international consensus on CGM targets. Therefore, in 2017 the Swedish Association for Pediatric Endocrinology and Diabetes decided to use 70–140 mg/dL (3.9–7.8 mmol/L) as target range for all pediatric age-groups with the ad- dition of CGM (real time or intermit- tently scanned) to treatment. In parallel with the development of the Swedish targets in 2017, the international con- sensus on time in range (TIR) (70–180 mg/dL, 3.9–10 mmol/L) was developed and published (6).
Then, in 2022, in its consensus guide- line “Managing Diabetes in Preschoolers” (7), the International Society of Pediatric and Adolescent Diabetes (ISPAD) recom- mended that for preschoolers with T1D and access to diabetes care of high qual- ity, either >70% of time with glucose in range 70–180 mg/dL (3.9–10 mmol/L) (TIR) or >50% of time in a tighter range, 70–140 mg/dL (TITR), can be used as a CGM target.
The purpose of this review is to share and discuss knowledge and experiences from working with TITR instead of TIR as a health-promoting strategy for pre- schoolers with T1D.
TITR COMPARED WITH TIR
The core difference between the two concepts TIR and TITR is philosophical. While TIR was introduced as a CGM metric corresponding to HbA1c (8), TITR (previously called time in target [9]) was defined to measure time in a state of normoglycemia; afterward, the correla- tion with HbA1c was sought for estima- tion of what proportion of TITR to recommend (9). TITR was defined ac- cording to the percentage of time with
CGM glucose readings within 70–140 mg/dL (3.9–7.8 mmol/mol) (10).
The basis for the suggested TIR target was that 70% of time in TIR corresponds to an HbA1c of $7% (53 mmol/ mol). For TITR, 50% of time correlates to HbA1c 6.5% (48 mmol/mol) (9). How- ever, an HbA1c of 7% (53 mmol/mol) correlates to 56%–84% TIR and 38%–42% TITR, depending on coefficient of variation (CV) (11,12).
In a study in children and adolescents a cutoff of 72% TIR was identified in order to identify individuals who achieved a TITR of $50%. Both TITR and TIR cor- relate with the average glucose and the fluctuation in glucose levels (CV). The correlation between TITR and TIR is high (0.95) (13). TITR is on average 20%–25% lower than TIR (12). TIR corre- lates to TITR (in a nonlinear way) but depends also on CV.
DISCUSSION
As insulin treatment improves, a reason- able goal is to strive for as much time with normoglycemia as possible, and this can easily be explained to families of CwD. In everyday diabetes care this can be moni- tored as TITR. For children with access to good diabetes treatment a currently realistic target can be at least half of the time in normoglycemic range, i.e., TITR >50%.
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