Endocrine Abstracts

Background- The reduced survival in acromegaly is strongly related to high serum Growth hormone (GH) concentrations. This increased mortality is proportional to the GH excess on day curve data and hence reduction can improve mortalilty to normal levels. The threshold of

cure has changed over the last three decades and additional parameters have been introduced to assess disease activity.

Aim- To compare GH measurement equivalence during day curve to post glucose load data within individuals in order to define a biochemical cure with sample efficiency. Subjects- 16 acromegalics, 10 male & 6 female were selected according to standard criteria. All except two cases had a visible adenoma on MRI. 12 underwent transsphenoidal surgery and 4 had subsequent radiotherapy. 2 patients had primary medical therapy with a total of 6 patients on somatostatin analogues. 5 patients became hypopituitary as a result of surgery requiring replacement of the required axes. Design-Patients underwent a five point GH day curve with 120min sampling over 8 hours and a 75gram oral glucose tolerance test (OGTT) over 3 hours. Both tests were performed within a week of each other and a week prior to GH medical treatment. Results- We found a strong correlation between GH nadir after an OGTT and GH day curve mean concentrations (r=0.95, p<0.001). There was also strong a correlation between OGTT GH nadir and GH day curve trough (r=0.963, p<0.001). A weaker though significantly positive correlation was observed between OGGT GH nadir & age

matched IGF-1 (r=0.556, p=0.025). Although 5 patients had OGTT GH suppression to<2.6milliUnits per litre (1mg/l) indicating disease cure, 15 out of 16 had IGF-1 values within the reference range.Conclusion- This data suggests the GH nadir from an OGTT or a mean GH concentration from a day curve with a IGF-1 measurement is sufficient to assess disease activity.