This work was supported by Amylin Pharmaceuticals, Inc., San Diego, CA. DMB, MLM, MP and DLP have received funding from Amylin Pharmaceuticals, Inc. JHB and AC are employees of Amylin Pharmaceuticals, Inc. DLP has received honoraria from Amylin Pharmaceuticals, Inc. for participating in the development of the instrument, analysis of the data and preparation of this manuscript. MP has received honoraria from Amylin Pharmaceuticals, Inc. for participating in the analysis of the data and preparation of this manuscript.
MP provided input on the SMP-T2D development, participated in planning the analyses, performed statistical analyses and helped draft the manuscript. DMB performed statistical analyses and helped draft the manuscript. JHB participated in planning the study designs, participated in the SMP-T2D development, and helped draft the manuscript. MLM participated in the SMP-T2D development and helped draft the manuscript. AC helped draft the manuscript. DLP participated in the SMP-T2D development, participated in planning the analyses and helped draft the manuscript. All authors read and approved the final manuscript.
This study evaluated the measurement properties of a newly developed instrument – the Self-Management Profile for Type 2 Diabetes (SMP-T2D).
The 18-item SMP-T2D assesses 12 constructs: level and perceived ease of performance in five self-care domains (blood glucose monitoring, medication-taking, healthy eating, being physically active, and coping), and two global constructs (ease of weight management, confidence with ability to manage diabetes). Validation analyses were based on two studies involving 240 patients with T2D, Study 1 (Clinicaltrials.gov #NCT00637273) with SMP-T2D administration supplemented by SMP-T2D retest one week later, and Study 2 (Clinical trials.gov #NCT00877890) with SMP-T2D administration supplemented by 24-week SMP-T2D follow-up after medication change. Validation included clinical indicators and measures of patient reported quality of life, psychological well-being and treatment outcomes.
All multi-item SMP-T2D measures showed acceptable internal consistency (alphas = 0.71 to 0.87); ten measures had test-retest reliability >0.75. Correlations among SMP-T2D measures and between SMP-T2D measures and validation measures, which were as hypothesized, provided evidence of convergent and discriminant validity. Scores for six SMP-T2D measures improved significantly during Study 2. Multiple regression analysis showed independent associations between change in SMP-T2D measures and change in trial outcomes from baseline to end-of-study.
Two studies provide preliminary evidence regarding the reliability, validity and responsiveness of the SMP-T2D. Further research on the utility of the instrument is needed.