Weight Gain in Acromegaly Patients after Pituitary Surgery Is Substantial, Persists over Time, and Is Independent of Age, Baseline BMI, and Biochemical Control – a Large Single Center Experience
Presentation Number: SUN 446
Date of Presentation: April 2nd, 2017
Dawn Shao Ting Lim*1, Fabienne Langlois1, Elena Varlamov2, Jung Kim2, Christine G Yedinak2, Justin S Cetas2 and Maria Fleseriu2
1Oregon Health & Science University, OR, 2Oregon Health & Science University, Portland, OR
Acromegaly (A) is associated with body composition changes; GH/IGF-1 reduction results in ↓lean body mass and ↑total body fat. Uncontrolled A is associated with excess cardiovascular (CV) mortality. Weight is an important determinant of metabolic and CV risk. Few studies have examined the effect of pituitary surgery (Sx) and biochemical control for A on weight gain, with variable results. Aim: to determine prevalence and identify predictors of post-op weight gain in A.
Retrospective, IRB-approved review of A patients (pts) who had pituitary Sx at OHSU (2006–2015), with ≥12 months (mo) follow-up; weight, GH/IGF-1 and pituitary function were measured pre- and regularly post-op. Statistical analysis: PASW 18
56 pts were identified; 2 excluded (1 pregnant, 1 on weight loss program). 54 pts (31 F) were analyzed, median age 48 yrs (range, 18-77), baseline BMI 29.4kg/m2. Mean pre-op IGF-1 was 2.6 x ULN (±SD 1.30). 8 pts had previous pituitary Sx, 10 had pre-op medical therapy (5 on SRLs, 1 Peg, 4 DAs), 2 had RT. 41 were biochemically controlled 12mo after Sx (21 on med therapy), mean IGF-1 0.9 x ULN (±SD 0.5). 13 pts had adrenal insufficiency, all on physiologic hydrocortisone replacement. LT4 was adjusted to high normal FT4 in 13 hypothyroid pts.
Weight changed significantly from baseline to 12 mo post-op (p=0.001); mean +3.8% (±SD 7.2). 40/54 (76%) gained weight; 26 (48%) gained > 3%, 19 (35%) gained > 5%. Mean baseline IGF-1 was higher in pts who gained >3% than in those with <3% weight gain (3.1 vs. 2.2 x ULN, p=0.012). A moderate correlation was seen between baseline IGF-1 and % weight change in women (r=0.46, p=0.009). Age, baseline BMI and IGF-1 x ULN at 12mo were not significant predictors. Medication changes, including antidiabetic meds were examined and did not account for weight gain. Weight gain persisted at last follow-up (mean 49, ±SD 26mo; 89% in remission) in 37/54 (69%). 21 (39%) gained >3%, 13 (24%) gained >5%.
We found that weight gain was significant from baseline to 12 mo post-op. Overall, ¾ of pts gained weight, with almost half gaining >3% and a third gaining >5%. This persisted during longer-term follow-up in the majority. While weight gain in the general population predisposes to metabolic syndrome, and is a CV risk factor, the impact of persistent weight gain in pts treated for A needs further study. Our finding of greater weight gain in pts with more severe disease highlights that close attention should be paid to these pts. General education to manage weight changes should be instituted in parallel with treating the GH excess.
Weight gain is substantial in the majority of pts with A after Sx, independent of biochemical control; mechanism not completely understood. Predictive factors need further evaluation, but awareness is paramount in order to limit factors contributing to post-op weight gain, especially in pts with severe baseline disease.
Disclosure: MF: Principal Investigator, Novartis Pharmaceuticals, Ad Hoc Consultant, Novartis Pharmaceuticals, Principal Investigator, Chiasma, Ad Hoc Consultant, Chiasma, Principal Investigator, Pfizer Global R&D, Ad Hoc Consultant, Pfizer Global R&D. Nothing to Disclose: DSTL, FL, EV, JK, CGY, JSC