Endocrine Abstracts

Objective: To identify a range of IGF-I values representative of growth hormone deficiency (GHD), which could be utilised to reduce the risk of 'functional' GHD in Pegvisomant treated acromegaly.

Method: We analysed centrally measured IGF-I data from the KIMS European GHD database. We stratified this cohort into six gender based, age ranges and assessed IGF-I and IGF-I standard deviation scores (SDS).

Results: Baseline measurements from 376 females (median age 48, range 21-77 years) and 434 males (median age 52, range 21-80 years) were analysed. Data were not normally distributed and are presented as median (25th to 75th centiles). The median serum IGF-I and IGF-I SDS in males were 94.0 micrograms per litre (64 to 141) and -1.52 (-2.53 to -0.456), (n = 434). Both were significantly greater than that of females which were 73 micrograms per litre (46 to 103.5) and -2.30 (-3.28 to -1.328), (n = 376), (p= <0.0001 for both). IGF-I in females (r = -0.19, p < 0.01) and males (r = -0.32, p < 0.01) declined with age. In contrast IGF-I SDS in females (r = 0.12611, p <0.01) and males (r = 0.12611, p < 0.01) increased with age. Age and gender related 90th and 95th centiles for IGF-I and IGF-I SDS were determined.

Discussion: In an 'at risk' population with pituitary disease and deliberately lowered IGF-I levels such as Pegvisomant treated acromegalic patients, values above the age related 95th centile for GHD but within the normal age corrected range would carry only a 5% risk of functional GHD. These data may be used to select IGF-I or IGF-I SDS values commensurate with optimal control of Pegvisomant treated acromegaly, quantifying and maximally reducing the risk of functional GHD in this cohort with a sensitivity of 95%.