Prevalence of discordant GH and IGF-I levels in acromegalics at diagnosis, after surgical treatment and during treatment with octreotide LAR®

Background: Acromegalic patients are considered discordant if their insulin-like growth factor type I (IGF-I) levels are increased for their age with safe growth hormone (GH) levels or if their IGF-I levels are normal for their age with unsafe GH levels. The prevalence of discordance in acromegalics has been described to vary from 9.4% to 39%, and it may be observed at diagnosis or daring the follow up. Objective: To evaluate the prevalence of discordant levels of IGF-I and GH in our acromegalic population. Methods: Hormonal evaluation was made with an oral glucose tolerance test (OGTT) with the IGF-I being assessed in the basal sample at diagnosis and after 3 months of the adenomectomy. During treatment with octreotide LAR(R), a GH curve (for the calculation of mean GH) and IGF-I assessment were made every 3 months. Results: Among the 51 patients evaluated at diagnosis, the prevalence of discordance was 13.7% (7/51). Among the 58 patients evaluated after the surgical procedure, eight (13.8%) had discordant GH and IGF-I levels. Among the 42 patients evaluated during treatment with octreotide LAR(R), the prevalence of discordant GH and IGF-I levels was 33.3% (14/42). Using 1 mu g/L as a cut of level for safe GH, the prevalence of discordance was 3.9%, 8.'% and 28.6% at diagnosis, after surgery and during treatment with octreotide LAR(R). respectively. No difference of sex, age or treatment modality was observed among discordant and concordant patients with any GH cut off level. Conclusion: We observed a prevalence of discordance similar to that previously described in the literature. We believe that studies evaluating morbidity and mortality in discordant patients are also necessary and will enlighten the true impact of this condition in the follow tip of acromegaly. (C) 2008 Elsevier Ltd. All rights reserved.