Disease-oriented quality of life (QoL) measures that are not preference-based lack legitimacy for direct use in cost-utility analyses. This has prompted the search for other methods for deriving utilities. The QoL Assessment of Growth Hormone Deficiency in Adults questionnaire (QoL-AGHDA) is a disease-oriented measure used to assess impairment in QoL in adults with growth hormone deficiency. The present study was designed to generate a model for deriving utilities from the QoL-AGHDA.
The EQ-5D, the QoL-AGHDA, and demographic questions were mailed to a random sample (n = 3005) of the Swedish population (response rate 65%). Multiple regression analysis was used to obtain cross-validated parameters of QoL-AGHDA-based utilities. Two models were developed (simple and full versions). The simple version used the EQ-5D (derived from European values) as the dependent variable, and age, sex, and QoL-AGHDA score as independent variables in a regression analysis. The full model utilized all available demographic information. The QoL-AGHDA scores were thus transformed into a single score (0–1), corresponding to the QoL-AGHDA-based utility.
The simple transformation algorithm was U (QoL-AGHDA-based utilities) = 1.05 − 0.0189 × QoL-AGHDA score − 0.00238 × age − 0.0127 × sex (male = 0; female = 1). The mean of the weighted estimate for the population (n = 1752) was 0.85 (SD 0.10). The estimate for men (n = 861; mean 0.86; SD 0.10) was higher (P SD 0.10).
For practical reasons, the simple model can be recommended for deriving utilities directly from the QoL-AGHDA for the Swedish population.