Study Population

The present study was conducted with the participation of acromegaly patients admitted to the Department of Neurosurgery at the Peking Union Medical College Hospital (PUMCH) between January 2000 and October 2017. As shown in the Endocrine Society Clinical Practice Guideline on acromegaly (3), the preoperative diagnostic criteria for acromegaly are as follows: (1) adult patients with clinical symptoms of acromegaly (3), (2) PA confirmed by pituitary magnetic resonance imaging (MRI), and (3) preoperative IGF1 (pre-IGF1) values exceeding the upper limit of the age- and the gender-related reference range (19) and lack of suppression of GH to <1.0 ng/ml following documented hyperglycemia during an oral glucose load.

The inclusion criteria were as follows: (1) the acromegaly patients had undergone initial TSS conducted by the same experienced surgeons in the pituitary treatment group using a microscope or an endoscope in our hospital, (2) PAs had been confirmed by postoperative pathological examination, (3) at 6 months following surgery, the patients who did not meet the postoperative endocrine remission criteria [i.e., either postoperative random GH (post-rGH) levels <1.0 ng/ml or postoperative nadir GH (post-nGH) levels <0.4 ng/ml that were associated with normal age- and gender-matched IGF1 levels] (3, 4), (4) no history of radiotherapy or medical therapy following TSS, and (5) the patients had endocrine follow-up data for more than 18 months following TSS.

After screening, a total of 306 acromegaly patients were eligible for inclusion in the study. They were randomly divided into a training dataset (n = 244), which was used for model construction, and a test dataset (n = 62), which was used for model validation (i.e., a 4:1 ratio, respectively). This study was approved by the ethical review committee of the PUMCH, and the need for patients' informed consent was waived.