Growth Hormone Day Curve (GHDC) in the management of patients with Acromegaly. Can we cut down on the cost?

Background
Acromegaly is a clinical syndrome resulting from hypersecretion of Growth Hormone (GH). Biochemical tests used in managing Acromegaly include for GH, IGF-1, random GH and GHDC. GHDC is useful to assess clinical severity and response to treatment. This test is usually done as a 5-point test, but there is no widely accepted protocol regarding the timing of samples. Mean GH <5mU/L suggest adequate control of GH.
Objectives
To check if lesser number of samples can be used rather than five-point GHDC and to find the proportion of patients adequately responding to treatment.
Methods
This was a retrospective descriptive study done at Endocrinology department of TH Kandy. GHDC data were retrieved from clinic records and analyzed using Medcalc2019.
Results
Fifty-eight GHDCs of 30 patients were included in the final analysis. We compared 14 different combinations of four and three samples with the established way of 5-point sampling. All combinations showed 100% sensitivity in detecting adequate control while maintaining a specificity of 95 to 100%. There were 5 false positives where means ranged from 5.08 to 6.52 suggesting biochemically mild disease. Only one third of our patients had adequately controlled disease while most international data show better outcome.
Conclusions
Traditional GHDC may safely be replaced with a 4-point/3-point test while maintaining 100% sensitivity and slightly compromised specificity. There is a need to produce local data and to make advanced treatment modalities available in the public sector to improve patient outcome.