The impact of real practice inappropriateness and devices' inefficiency to variability in growth hormone consumption

Growth hormone (GH) consumption is the object of a particular attention by regulatory bodies, due to its financial impact; nevertheless, GH treatment has been demonstrated to be cost-effective and is, therefore, usually reimbursed by public health service systems. In Italy, significant differences in GH consumption between regions have been recorded. Different appropriateness in real practice is a possible explanation, but the proportion of drug wasted due to different combinations of therapeutic regimes and types of devices used in drug administration is a complementary explanation. Aim of the study is, therefore, to determine how much of the variability in GH consumption is actually due to differences in clinical practice, and how much to waste.

A model was settled to estimate the population with indication for GH administration, separately for children, transition subjects and adults, based on both the scientific evidence available and directly collected clinical evaluations. A systematic literature search was conducted using Cochrane Library (HTA and NHSEE) databases, Medline via Ovid, Econlit via Ovid, Embase.

The model applied to the Italian population showed that there was apparently unexplainable over-prescription and potential under-prescription in various regions, ranging from 20 to 40 % less than the estimated theoretical consumption to over 200 %. Wastage, at level of single device, could amount to as much as 15 % of the consumption, demonstrating that price per mg is not in general a good proxy of the cost per mg of therapy. Our estimates of the wastage shows a significant potential gap in the model assessment of the HTA bodies, as far as they do not explicitly take into account the issue of wastage and, consequently, the actual variability in local clinical practice.