Validation of the Diabetes Numeracy Test With Adolescents With Type 1 Diabetes

Abstract

There is currently a lack of valid instruments to measure adolescent diabetes numeracy. The Diabetes Numeracy Test (DNT) was adapted for type 1 diabetes and was administered to 2 samples of adolescents. Sample 1 was administered the 39-item version of the DNT (DNT-39) with measures of self-management, responsibility, reading, and glycemic control (A1C). Sample 2 was administered the 14-item version of the DNT (DNT-14) with measures of self-management, responsibility, problem solving, and A1C. Both versions of the DNT showed adequate internal reliability. In Sample 1, the DNT-39 and DNT-14 were related (r = .87, p = .001), and both DNT versions were related to parent education (for DNT-14, r = .31, p = .02; for DNT-39, r = .29, p = .03) and reading (for DNT-14, r = .36, p = .005; for DNT-39, r = .40, p = .001). In Sample 2, the DNT-14 was related to A1C (r = −.29, p = .001), reading skills (r = .36, p = .005), diabetes problem solving (r = .27, p = .02), adolescent age (r = .19, p = .03), and parent education (r = .31, p = .02). In combined analyses, 75% of items were answered correctly on the DNT-14 (range = 7–100), and performance was associated with age (r = .19, p = .03), pump use (r = .33 p = .001), and A1C (r = −.29, p = .001). The DNT-14 is a feasible, reliable, and valid numeracy assessment that indicated adolescents with type 1 diabetes have numeracy deficits that may affect their glycemic control.

Acknowledgments

The research was supported by DK070026 to Dr. Mulvaney, and K23 DK065294 and Vanderbilt Diabetes Research and Training Center Pilot and Feasibility Program grant K020593 to Dr. Rothman. Dr. Cavanaugh is supported by K23 DK080952.

Notes

Note. DNT-14 = 14-item version of the Diabetes Numeracy Test; DNT-39 = 39-item version of the Diabetes Numeracy Test; NA = not available.

Note. DNT-14 = 14-item version of the Diabetes Numeracy Test; DNT-39 = 39-item version of the Diabetes Numeracy Test; SSCA-R = Summary of Diabetes Self-Care Activities–Revised; WRAT-3 = Wide Range Achievement Test–3.

Note. DBRS = Diabetes Behavior Rating Scale; DNT-14 = 14-item version of the Diabetes Numeracy Test.

Note. DNT-14 = 14-item version of the Diabetes Numeracy Test.