GH1 and acromegaly: Early postoperative GH levels can determine whether patients with acromegaly can achieve long-term remission, including GH levels on postoperative day one (POD1) and day two, the mean of multiple GH measurements between 1 week and 3 weeks after neurosurgery, and nadir GH after an oral glucose tolerance test at least 7 weeks after neurosurgery, particularly the GH level on POD1 (i.e., POD1GH).