Early postoperative measurement of growth hormone level for prognosis of surgical outcomes in acromegaly

Aim. To investigate the value of 24 hours post-surgery measurement of growth hormone (GH) level for prognosis of surgical outcomes in acromegaly.

Materials and methods. A prospective cohort study included 45 patients with newly diagnosed acromegaly. The degree of parasellar extension was measured on the preoperative sellar magnetic resonance imaging according to the Knosp’s classification. All patients underwent a transsphenoid adenomectomy performed by one neurosurgeon. Basal GH level was measured at 24 hours after surgery. The efficacy of transsphenoidal adenomectomy evaluated at 12 months after surgery.

Results. Acromegaly remission was achieved in 19 (42%) of 45 patients at 12 months after surgery. Pituitary microadenomas and the absence of paracellular invasion, corresponding to Knosp Grade 0–2, had low prognostic value for long-term remission due to low sensitivity (31.6%) and low specificity (38.5%), respectively. The highest prognostic value for acromegaly remission was showed for 24 hours post-surgery GH level with cut-off <1.30 ng/ml with sensitivity of 96.2% (95% confidence interval 81.1–99.8%) and specificity of 84.2% (95% confidence interval 62.4–94.4%).

Conclusion. The study demonstrated the possibility of using GH level at 24 after surgery as a predictor for acromegaly remission. GH level <1.30 ng/ml at 24 hours after surgery showed better predictive value for long-term remission compared with the presence of microadenomas and Knosp Grade 0–2. The absence of decrease of GH level on the first day after surgery may serve as a reason for more close monitoring of patients in the postoperative period. Further studies in a larger number of observers are required to confirm our findings.