Year, Volume, Issue, Page(s):15, 38, 3, 335-346
Article describes the development and psychometric properties of the Spinal Cord Injury – Quality of Life (SCI-QOL) Depression item bank, computer adaptive test (CAT), and short form to assess depressive symptoms experienced by individuals with spinal cord injury (SCI). Grounded-theory-based qualitative item development methods and large-scale field testing were used. Analyses included confirmatory factor analysis, item response theory (IRT) calibration, and evaluation of differential item functioning. Scores were transformed to the Patient Reported Outcomes Measurement Information System (PROMIS) metric and statistical linking techniques were used to develop a crosswalk to the Patient Health Questionnaire (PHQ)-9. The item pool was tested at several medical institutions across the United States, including 5 SCI Model System centers and one Veterans Affairs medical center. A sample of 716 individuals with traumatic SCI completed 35 items assessing depression, 18 of which were PROMIS items. After removing 7 non-PROMIS items, factor analyses confirmed a unidimensional pool of items. A graded response IRT model was used to estimate slopes and thresholds for the 28 retained items. The SCI-QOL Depression measure correlated with the PHQ-9. The SCI-QOL Depression item bank provides a reliable and sensitive measure of depressive symptoms with scores reported in terms of general population norms. A crosswalk to the PHQ-9 was created to facilitate comparisons between measures. The item bank may be administered as a CAT or as a short form and is suitable for research and clinical applications.