A Three-Part Model for Measuring Diabetes Care in Physician Practice

Background To assess the psychometric properties of the three components of the Diabetes Practice Improvement Module, to compare reliabilities of composites to individual measures, and to identify associations among practice-based and patient-based measures. Method Data include practice systems surveys of 626 physicians, 13,965 chart audits, and 12,927 patient surveys. Quality composites were identified using factor analysis. Means with reliabilities (intraclass correlation coefficient [ICC] and Cronbach’s α) are reported. Associations among patient-based quality measures and practice measures with case-mix adjustments were estimated via hierarchical models. Results Composite ICCs range from 0.11 to 0.54, and single items range from 0.05 to 0.49. Staff communication, efficiency, care access, and patient knowledge correlate with patient satisfaction (P < .001). Clinical outcomes are associated with clinical processes (e.g., annual foot exam) and appropriate treatment (P < .001). Patient adjusters (e.g., overall health or factors limiting self-care) are important for the models; physician characteristics used (e.g., age, practice size) seem less important. Conclusions Composites require smaller patient sample sizes and result in more reliable measures than do individual items. Additionally, the data show meaningful relationships between composites; physician-directed components (i.e., clinical processes and treatments) are related to clinical outcomes, and patients are clearly more satisfied with care if it is easily accessible and if communication about care is good.