Development of a New Measure of Housing Security: The REDD-CAT Housing Security Measure.

BACKGROUND: Housing security is a key social determinant of behavior related to health outcomes. OBJECTIVE: The purpose of this study was to develop a new patient-reported outcome measure that evaluates aspects of housing security for use in the Re-Engineered Discharge for Diabetes-Computer Adaptive Test (REDD-CAT) measurement system. DESIGN: Qualitative data, literature reviews, and cross-sectional survey study. PARTICIPANTS: A total of 225 people with T2DM provided responses to the items in this item pool. MAIN MEASURES: A new item pool that evaluates important aspects of housing security was developed using stakeholder data from focus groups of persons with T2DM. KEY RESULTS: For the Housing Affordability scale, factor analysis (both exploratory and confirmatory) supported the retention of six items. Of these items, none exhibited sparse cells or problems with monotonicity; no items were deleted due to low item-adjusted total score correlations. For the six affordability items, a constrained graded response model indicated no items exhibited misfit; thus, all were retained. No items indicated differential item functioning (examined for age, sex, education, race, and socioeconomic status). Thus, the final Affordability item bank comprised six items. A Housing Safety index (three items) and a Home Features index (eight items) were also developed. Reliability (i.e., internal consistency and test-retest reliability) and validity (i.e., convergent, discriminant, and known-groups) of the new measures were also supported. CONCLUSIONS: The REDD-CAT Housing Security Measure provides a reliable and valid assessment of housing affordability, safety, and home features in people with type 2 diabetes mellitus. Future work is needed to establish the clinical utility of this measure in other clinical populations.