Improving Time-in-Range in Type 1 Diabetes: Projecting the Clinical and Cost Implications of Automated Insulin Delivery.

Introduction: Time in range (TIR) has emerged as a key target in managing people with type 1 diabetes (PwT1D). The time spent in a glucose range of 70-180 mg/dL (3.9-10.0 mmol/L; TIR) is recommended to be >70%, which has been linked to reduced complication incidence. While frequently used in evaluating automated insulin delivery, TIR has rarely been applied in health economic assessments. This analysis therefore examined the impact of a 10-percentage point increase in TIR on clinical and economic outcomes for PwT1D. Methods: Four baseline TIR levels (50%, 60%, 70%, 80%) and the investigated TIR increase were mapped to glycated hemoglobin (HbA1c) using two published statistical approaches. HbA1c estimates informed the IQVIA CORE Diabetes Model, projecting cumulative complication incidence, life expectancy, quality-adjusted life expectancy (QALE), and costs over 20 years from an English public health care system perspective. Cohort baseline data, complication costs, and utilities were sourced from an economic assessment by the National Institute for Health and Care Excellence. Sensitivity analyses were performed to assess the robustness of results. Results: A 10-percentage point TIR increase reduced the cumulative incidence of complications, by 15.6%-53.0%, 8.8%-47.1%, 8.1%-33.5%, and 10.1%-17.6% for ophthalmic, renal, neuropathic, and cardiovascular complications, respectively, when averaged across baseline TIR levels. Fewer complications translated into life expectancy gains of 0.031-0.051 years and QALE gains of 0.056-0.143 quality-adjusted life-years, with higher gains for lower baseline TIR. Total projected cost reductions versus constant TIR were 7.5%-9.9%, driven by reduced complication costs. Conclusions: Long-term projections for England suggested that a 10-percentage point increase in TIR reduced diabetic complications in PwT1D, thereby reducing spending on complication treatment. Improvements were seen across baseline TIR levels but were disproportionately accrued in those with lower baseline TIR.