An early paradoxical GH increase after glucose load characterises non-acromegalic patients with high IGF-1 levels

Objective: An incomplete GH suppression after oral glucose tolerance test (OGTT) is the hallmark of acromegaly diagnosis. A proportion of patients with acromegaly present a paradoxical GH rise (GH-Par) after glucose administration. We aimed to study if GH-Par response after glucose load can characterize patients without acromegaly. Design: Observational case-control study in a referral centre. Methods: We recruited patients with suspected acromegaly (n=176), characterized by increased IGF-1 levels (GH nadir >0.4 µg/L defined acromegaly), and 55 matched controls (normal IGF-1 and suppressed GH). GH-Par90min was defined as GH peak ≥120% over basal levels at latest 90 minutes after glucose intake.