Assessment of GH status in adults with GH deficiency using serum growth hormone, serum insulin‐like growth factor‐l and urinary growth hormone excretion

Publisher Website
Google Scholar
Abstract
OBJECTIVES The benefits of treating adults with G H deficiency are now well recognized although the criteria for deciding which patients to treat are still not clear. At present the ‘gold standard’ Is the Insulin stress test (IST) which Is unpleasant and potentially dangerous, particularly in patients with hypopituitarism. The aim of this study was to determine whether alternative methods of assessing GH status are reliable in predicting GH deficiency. SUBJECTS AND METHODS Forty‐four patients with unequivocal G H deficiency (peak 1ST or more other pituitary axes were affected (90%). U G H declined significantly with the level of peak 1ST response (P < 0‐001) and almost so with the number of other deficient hypothalamic‐pituitary axes affected (P= 0‐057). Thus, u G H accurately reflected G H status and showed good separation from normal controls In patients less than 40 years (specificity 79%) and between 40 and 60 years (specificity 67%). Above this age the method is less specific (36%). Patients excreted significantly less G H than controls in all three age groups (P < 0.01). Subnormal levels of IGF‐I were strongly predictive of unequivocal G H deficiency (91 % with subnormal IGF‐I have a peak 1ST G H lt; 2 mU/l) although a normal value does not reliably exclude the diagnosis. CONCLUSIONS A diagnosis of adult G H deficiency can be reliably made without the need for an insulin stress test by using a combination of low urinary G H excretion, subnormal I G F‐I levels and clinical assessment with regard to the number of other pituitary axes affected.