Longitudinal construct validity of the Health Utilities Indices Mark 2 and Mark 3 in hip fracture

Purpose

The objective of this study is to evaluate the longitudinal construct validity of the Health Utilities Index Mark 2 (HUI2) and Health Utilities Index Mark 3 (HUI3) using a convergent/divergent validity approach in patients recovering from hip fracture, with the Functional Independence Measure (FIM) as the comparator.

Methods

A total of 278 patients with a primary diagnosis of hip fracture were interviewed 3–5 days after surgery and then at 1 and 6 months using the HUI2, HUI3 and the FIM and a Likert-type rating of hip pain. A priori hypotheses were formulated. Convergent and divergent correlations between HUI2, HUI3 and FIM change scores for the baseline to 1-month and baseline to 6-month intervals were examined.

Results

Overall HUI2 detected continued gain in health-related quality of life between 1 and 6 months after fracture, as the change increased from 0.20 to 0.29 units. The correlation between change in the overall HUI2 score and total FIM score was moderate (r = 0.50) over the 6-month interval, but larger than the observed correlation over the 1-month interval (r = 0.36). The correlation between change in overall HUI3 score and total FIM over the 1-month interval was small (r = 0.32), and the correlation between change in overall HUI3 score and total FIM was moderate (r = 0.37) over the 6-month interval. All hypotheses for the divergent correlations were supported.

Conclusions

Weaker correlations were reported for change over 1 month as compared to change over the 6 months after fracture. Findings supported the longitudinal construct validity of the overall HUI2 and HUI3 for the assessment of recovery following hip fracture, particularly for change over the 6 months following fracture.