It was with great interest that we read the recent report by Gilet and colleagues in the recent edition of Value in Health [1]. Gilet et al. [1] attempted to develop a normative database for the quality of life assessment in growth hormone deficient adults (QoL-AGHDA). Unfortunately, the article demonstrates a number of misunderstandings of the nature of patient-reported outcome measurement, the value of population norms, and the application of Rasch analysis.

The QoL-AGHDA is a measure of quality of life (not health-related quality of life as stated in the article) that is specific to patients with growth hormone deficiency. Its content was derived from such patients and was never intended to be completed by healthy individuals. For the QoL-AGHDA to be valid for use with a healthy population it would first be necessary to show that it is psychometrically strong for such a group and that their responses to the items fit the Rasch model. In order to allow comparisons to be made between growth hormone deficient (GHD) patients and a general population it would also be necessary to establish that the scale works in the same way with both groups. None of these issues was adequately addressed in the article.