The construct validity of the health utilities index mark 3 in assessing health status in lung transplantation

To assess the cross-sectional construct validity of the Health Utilities Index Mark 3 (HUI3) in lung transplantation.

Two hundred and thirteen patients (103 pre-transplant and 110 post-transplant) with mean age 53 years old (SD 13) were recruited during a randomized controlled clinical trial at the out-patient clinic in a tertiary institution. At baseline, patients self-completed measures that included the HUI3, EuroQol EQ-5D, Hospital Anxiety and Depression Scale (HADS) and socio-demographic questionnaire. Six-minute walk test scores and forced expiratory volume in 1 second data were collected from patient's medical records. A priori hypotheses were formulated by members of the transplant team about the expected degree of association between the measures. Correlation coefficients of < 0.1 were considered as negligible, 0.1 to < 0.3 as small, 0.3 to < 0.5 as medium, and ≥ 0.5 as large.

Of the ninety predictions made, forty three were correct but in 31 the correlation was slightly lower than predicted and in 7 the correlations were much higher than predicted. In 48% of the cases, predicted and observed associations were in agreement. Predictions of associations were off by one category in 42% of the cases; in 10% of the cases the predictions were off by two categories.

This is the first study providing evidence of cross-sectional construct validity of HUI3 in lung transplantation. Results indicate that the HUI3 was able to capture the burden of lung disease before transplantation and that post-transplant patients enjoyed higher health-related quality of life than pre-transplant patients.