Validating the AdultCarbQuiz: A Test of Carbohydrate- Counting Knowledge for Adults With Diabetes

The risk of hypoglycemia is a major barrier to intensifying medical therapy in patients with diabetes who use insulin secretagogues or exogenous insulin.1–3 By promoting the transport of blood glucose into insulin-sensitive tissues, these medications can cause hypoglycemia if their action is not counterbalanced by carbohydrate intake. Conversely, excessive carbohydrate intake can override the effect of hypoglycemic agents, resulting in postprandial hyperglycemia. Daily patterns of glycemic control are profoundly influenced by the interaction of diabetes medications with carbohydrate intake. Patients who do not recognize carbohydrate foods and those who cannot accurately estimate the number of carbohydrate grams in foods may vary their carbohydrate intake unknowingly. In addition, many patients are under the impression that eating a large meal rather than amount of carbohydrates consumed, is the greatest determinant of the magnitude of the postprandial blood glucose excursion. For this population of patients trying to regulate daily blood glucose levels, ignorance of carbohydrate intake exposes them to unpredictable, potentially dangerous glycemic variability. For clinicians trying to prescribe appropriate medication regimens, interpreting blood glucose patterns is problematic when patients cannot report (or cannot report correctly) the missing variable of carbohydrate intake. Carbohydrate counting is a mealplanning method that can be used in diabetes self-management to estimate carbohydrate intake. Much of the published experience with this methodology arose from the practicalities of managing patients with type 1 diabetes who participated in the landmark Diabetes Control and Complications Trial.1,4 The American Diabetes Association has acknowledged that monitoring the pattern and amount of carbohydrate in patients’ diets is key to achieving glycemic control.5 However, studies of patients with either type 1 or type 2 diabetes show that knowledge deficits regarding diet and hypoglycemia are substantial.6 Although monitoring and controlling carbohydrate intake are behaviors that may be influenced by factors other than knowledge, knowledge is a prerequisite for informed behavior, and for this reason, current diabetes standards of care include patient education about basic carbohydrate counting.2,3,7 To identify patients who are appropriate candidates for intensification of medication therapy, clinicians need to be able to assess patients’ knowledge of carbohydrate counting. To improve efficiency and effectiveness of the carbohydratecounting meal-planning approach, registered dietitians (RDs) and other diabetes educators need to be able to assess gaps in patients’ understanding of carbohydrate counting. Currently, there is no validated instrument specifically focused on testing carbohydrate knowledge among adult patients with diabetes.