Paradoxical GH increase during oral glucose load may predict overall remission in acromegalic patients

The nadir growth hormone (nGH) during the oral glucose tolerance test (OGTT) is the gold standard method for diagnosing acromegaly. A paradoxical growth hormone (GH) response to oral glucose (OG) in acromegaly can be observed. The role of the paradoxical GH response on how the patients with acromegaly respond to the treatment has been addressed in few studies. The aim of this study was to investigate the association between glucose-dependent growth hormone results and and the responses of acromegalic patients to surgical and/or medical therapy following surgery.

This retrospective cohort study included patients with acromegaly who underwent surgery (n = 189) or received primary medical treatment (n = 9). The mean age was 50.44 ± 12.81 years (M/F: 84/114). The patients were grouped into paradoxical (GH-P) and non-paradoxical (GH-nP) according to GH response to OG and were compared in terms of clinical and pathological features, pituitary tumor size, invasiveness, biochemical profiles, and how they responded to the treatment.

The mean age, gender distribution, and basal tumor diameter were all similar in both groups (p > 0.05). The GH-P group had a higher remission rate in response to medical therapy followed by surgery (83% vs. 55%; p = 0.026). Although a higher surgical remission rate in favor of GH-P was observed, it did not reach statistical significance (63% vs. 48%; p = 0.059). Overall treatment response rates were also higher in the GH-P group compared to the GH-nP group (89% vs. 71%; p = 0.005).

A paradoxical GH response to OG load may help to predict the response to medical treatment in patients with acromegaly.