New Consensus Report Defines Clinically Meaningful T1D Outcomes

Despite the value of HbA1C to clinical management, there are limitations to what it can tell patients and physicians
Despite the value of HbA1C to clinical management, there are limitations to what it can tell patients and physicians

Representatives from the American Association of Clinical Endocrinologists, the American Association of Diabetes Educators, the American Diabetes Association, the Endocrine Society, JDRF International, the Leona M. and Harry B. Helmsley Charitable Trust, the Pediatric Endocrine Society, and the T1D Exchange have come together to issue a new report standardizing clinically meaningful outcome measures for type 1 diabetes (T1D), beyond using HbA1c testing. The Consensus Report was published in the journal Diabetes Care.

Specifically, consensus definitions were developed for hypoglycemia,  hyperglycemia, time in range (proportion of time in glucose target ranges during continuous glucose monitoring [CGM]), and diabetic ketoacidosis (DKA).

The Steering Committee defined hypoglycemia in 3 levels: Level 1 (glucose <70mg/dL but ≥54mg/dL); Level 2 (glucose <54mg/dL); Level 3 (a severe event characterized by altered mental and/or physical status requiring assistance). "Given the differences in the outputs from [self-monitoring of blood glucose] and CGM, researchers and clinicians need to determine how the results are interpreted and when the blood glucose level requires a corrective action," the authors write. 

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Hyperglycemia in patients with T1D was defined in 2 levels: Level 1 (glucose >180mg/dL and ≤250mg/dL) and Level 2 (>250mg/dL). The authors note that additional studies are needed to better understand the effects of individual episodes of hyperglycemia versus sustained hyperglycemia over time. 

Time in range for patients with T1D was defined as the percentage of readings in the range of 70–180mg/dL per unit of time. The high and low bounds of the definition are consistent with the definitions for hypo- and hyperglycemia. Where HbA1c levels are measured at marked timepoints (months apart), time in range measures glucose changes continuously and is likely to reflect the impact of acute corrective actions. 

DKA in patients with T1D in a clinical setting was defined as elevated serum or urine ketones (greater than the upper limit of normal range), and serum bicarbonate <15mmol/L or blood pH <7.3. As each episode of DKA should be considered serious, the Steering Committee found it unnecessary to separate DKA into different categories.

With regard to patient-reported outcomes (PROs), the Food and Drug Administration (FDA) initially defined it as "any report of the status of a patient's health condition that comes directly from the patient, without interpretation of the patient's response by a clinician or anyone else." Evaluating PROs can help gather data on which parts of healthcare need improvement. Its use in T1D research is not widespread and more work is needed to develop standard PROs for T1D (eg, patient burden).

"This Consensus Report is a significant step towards providing standardized methods for improving how we evaluate therapies and technologies designed to treat and assist in the management of T1D and the prevention of its complications," said ADA's Chief Scientific, Medical and Mission Officer William T. Cefalu, MD. "Together, expanded data provided by CGMs along with uniform definitions will ultimately help us provide more carefully crafted and individualized diabetes care plans, and thus improve health outcomes as well as patient quality of life."

For more information visit diabetesjournals.org.