Test–retest reliability of health utilities index scores: Evidence from hip fracture
Objectives: There is relatively little evidence on the test–retest reliability of utility scores derived from multiattribute measures. The objective was to estimate test–retest reliability for Health Utilities Index Mark 2 (HUI2) and Mark 3 (HUI3) utility scores in patients recovering from hip fracture.
Methods: We enrolled an inception cohort of hip fracture patients within 3 to 5 days of surgery. Baseline assessments included the Functional Independence Measure (FIM™), Folstein Mini-Mental State Examinations, and the HUI2 and HUI3 questionnaire. Follow-up assessments at 1, 3, and 6 months also included a global change question. Test–retest reliability was assessed as agreement between 3- and 6-month scores using the intraclass correlation coefficient (ICC). Two approaches were used to classify patients as stable; a third approach based on the generalizability theory was also used. Patients were classified as stable if their FIM™ overall scores changed by 10 points or fewer and if they classified themselves as having experienced no or only a little change according to their global change question.
Results: Complete data at both the 3- and 6-month assessments based on self-report were available for 196 patients; 141 patients with complete data were classified as stable. The ICCs for HUI2 and HUI3 for stable patients were 0.71 and 0.72; the ICCs derived from the generalizability theory were 0.76 and 0.77.
Conclusions: Test–retest reliability for HUI in this cohort was similar to reliability estimates for other preference-based multiattribute and generic health-profile measures—in the acceptable range for making valid group-level comparisons.
Key Words: Test–retest reliability; Health Utilities Index; HUI; Hip fracture.