Effects of Diabetes Numeracy on Glycemic Control and Diabetes Self-Management Behaviors in Patients on Insulin Pump Therapy

Abstract

Introduction: Diabetes numeracy (DN) skills are crucial in patients on insulin pump therapy. Little evidence exists regarding DN in this patient population. Methods: This exploratory, observational, cross-sectional study assessed the DN levels of patients on insulin pump therapy and potential relationships with glycemic control and self-management behaviors. Seventy-two patients on insulin pump therapy were recruited from one specialty endocrinology clinic. Subjects completed validated tools to measure DN [Diabetes Numeracy Test (DNT-15)] and self-management behaviors [Diabetes Self-Management Questionnaire (DSMQ)]. A general diabetes questionnaire assessed socioeconomic information and self-efficacy. Additional self-management behaviors and glycemic control data were collected from patients’ medical records. Patients were categorized into two groups based on DNT-15 scores to explore potential relationships between DN scores and patient characteristics, glycemic control, and self-management behaviors. Results: Average age was 52 ± 15 years, glycosylated hemoglobin (A1C) was 7.7% ± 1.2% (61 mmol/mol), duration of diabetes was 28 ± 15 years, and duration of pump use was 3.4 ± 1.3 years. The average DNT-15 score was 87.5% ± 18%. Forty-three participants (60%) scored ≥ 90% and 29 participants (40%) scored < 90%. Eighteen percent were unable to calculate the carbohydrate content from a nutrition label. Participants with lower DNT-15 scores had higher A1C levels (8.0% vs. 7.5%, p = 0.04), were older (58.3 vs. 47.7, p = 0.003), were more likely to describe their diabetes self-care as poor (p = 0.04), and were less confident in using their pump features (p = 0.02) than those with higher DNT-15 scores. Conclusion: Many patients on insulin pump therapy have deficiencies with DN which may be associated with older age and higher A1C levels.