Validity and Reliability of a (Brief) Diabetes Survival Skills Knowledge Test: KNOW Diabetes

Purpose The purpose of this study was to determine the validity and reliability of the KNOW Diabetes test, a survival skills knowledge test, in identifying essential self-care knowledge deficits in adults with type 2 diabetes mellitus (T2DM). Methods The study was conducted in 3 United States cities among adults with T2DM. A pilot feasibility phase was followed by a validation phase. Both traditional and item response theory (IRT)-based analyses were conducted. Test items were scored against an answer key. Descriptive statistics, internal consistency evaluation using Cronbach's alpha, IRT, reliability assessment using test-retest correlation, and construct validity analyses were conducted. Results Consented adults (n = 280) with T2DM completed the study. In phase 1 (n = 53), the feasibility of implementation was demonstrated and resulted in a 15-question survey. In phase 2, participants (n = 227) completed the survey, with a subgroup (n = 54) completing it in a test-retest fashion. The test showed acceptable psychometric properties including unidimensionality, local independence, and differential item functioning. Concurrent validity testing showed that patients who are older, have a lower level of education, have Medicare or Medicaid, and have foot pain or numbness scored significantly lower than patients who did not. Divergent validity was assessed by testing differences between other comorbidities and revealed all tests to be nonsignificant. Conclusions The KNOW Diabetes test is appropriate for identifying knowledge deficits in diabetes self-management survival skills.