Citations

Abstract Disclosure: B. Graner: None. D.Z. Erickson: None. D. Donegan: None. Introduction: Pituitary lesions are a common incidental finding on brain MRI, the majority of which are cystic. The natural history and management of cystic pituitary lesions have not been clearly established. Purpose: The purpose of this study is to determine the natural history of incidentally identified cystic pituitary lesions, risk factors for growth and the proportion of patients who develop clinically significant symptoms requiring surgical intervention. Methods: Pituitary MRI reports between 01/01/2015 and 12/31/2022 in patients aged 18 years and older were searched for using Dig Our Radiology Information System (DORIS) using the words “cyst” or “cystic.” Additional inclusion criteria included a follow-up pituitary MRI of at least one year duration, clinical evaluation by Endocrinology, and the presence of a cystic pituitary lesion. Patients with non-contrast exams, excessive pituitary hormone secretion, and surgery within 1 year of presentation were excluded. Patient demographics, imaging characteristics of the lesion and clinical outcomes were collected. All pituitary MRI exams were reviewed by a single neuroradiologist. Results: A total of 157 MRIs in 56 patients with a mean age of 48 ±15 years were included, 39 (70%) were female. The mean follow-up was 2.3 ± 1.4 years. The most common indication for MRI was headache (n= 18, 32%). There was no significant difference in mean maximum (max) diameter at last follow-up compared to baseline (7.45 ±4.23 vs 7.04 ±4.35 mm, p=0.06) or mean cyst volume (197.08 ±252.68 vs 201.43 ±326.18 mm3). Nine (16%) of the lesions increased in volume with a mean change in volume of 105 ±133.64 mm3/yr, note 11 (20%) decreased volume and 36 (64%) remained the same size. Using univariate logistic regression, the odds of cyst growth was greater the larger the max diameter (p= 0.03) or volume was at baseline (p= 0.02)/ Female sex (p=0.32), age at diagnosis (p=0.70) or whether the lesion was thought to be a Rathke cleft cyst or a cystic adenoma (p=0.80) were not associated with increased odds of growth. The risk of growth was higher (42 vs 9%, p=0.016) and the volume change per year was greater (67.2 ±134 vs -7 ±28 mm3, p=0.04) in those with a baseline max diameter of >10 mm. Surgery was performed in 4 patients (7%), 3 of which demonstrated lesion growth (baseline size 12-15 mm and growth rates of 59-341mm3/yr). Pathology revealed one Rathke cleft cyst, one cystic adenoma and fibrotic pituitary changes. The fourth surgical patient opted for resection at an outside facility without a demonstrated increase in size (Rathke cleft cyst). Conclusion: The majority of incidentally found cystic pituitary lesions do not increase after an average follow-up 2-3 years. Growth necessitating surgical intervention was only required in 5% of patients over the study period. A pituitary cyst >10 mm at diagnosis was associated with an increased risk of growth and therefore warrants closer follow-up. Presentation: 6/1/2024

Abstract Disclosure: A.L. McKenna: None. S. Thota-Kammili: None. K. Grennan: None. S. Rao: None. It is known that thyroid dysfunction is an adverse effect of tyrosine kinase inhibitors (TKIs) via inhibition of the vascular endothelial growth factor receptor (VEGFR). The VEGF signaling pathway is important in regulating angiogenesis in tumors and normal tissue. As a highly vascularized gland, it is expected the thyroid may be compromised because of VEGFR inhibitors. Proposed mechanisms of thyroid dysfunction include capillary regression and constriction leading to reduced vascular perfusion to the gland. Bevacizumab is a monoclonal antibody that targets VEGF and inhibits activation of VEGFR, reducing angiogenesis; interestingly, this is not commonly reported in the literature. Here we present a case where bevacizumab altered thyroid function in a patient with pre-existing primary hypothyroidism. A 60-year-old woman presented with worsening hypothyroidism. She reported a history of nonautoimmune primary hypothyroidism diagnosed in her early 20s; she still had an intact thyroid with no history of head/neck radiation. In the months leading to the presentation, she had been receiving maintenance chemotherapy with 5 fluorouracil and bevacizumab every 2 weeks for metastatic duodenal carcinoma. Prior to starting chemotherapy, she had been on a steady dose of 112 mcg of levothyroxine (LT4) daily. After 6 months on chemotherapy, she reported symptoms of fatigue and hair loss. Workup revealed an elevated TSH of 41 mIU/L (reference 0.3-4.2 mIU/L). She denied any significant changes in weight or malabsorption issues. Aside from the chemotherapy, no other new medications were introduced. Her LT4 dose was increased to 137 mcg daily, and 3 months later, there was improvement in TSH to 6.5 mIU/L as well as her symptoms. At this point, bevacizumab was briefly on hold for 2 months due to an upcoming procedure, hence there was no change to LT4 to avoid over correction. Her TSH normalized and was trending lower while bevacizumab was on hold. Once bevacizumab resumed, LT4 was preemptively increased to 150 mcg daily. Four months after resuming bevacizumab, her TSH remains within the normal reference range on 150 mcg LT4. It is hypothesized that this VEGF blocker led to worsening of her underlying hypothyroidism.Given the shared down regulation in the VEGF signaling pathway, it would be expected that TKIs and monoclonal antibodies against VEGF would share similar adverse reactions to the thyroid. However, to our knowledge, there have been limited reports of bevacizumab induced thyroid dysfunction in the literature. Explanations to this may include the more targeted VEGF inhibition with bevacizumab versus the inhibition of multiple kinase receptors from the TKIs. Further research into this will be needed. This case demonstrates that bevacizumab can impact thyroid function and thyroid labs may need to be monitored at the onset and during VEGF inhibitor therapies. Presentation: 6/3/2024

Abstract Disclosure: O. Hamidi: Advisory Board Member; Self; Corcept, Neurocrine Biosciences, Amryt Pharma, Recordati Rare Diseases, Lantheus, Xeris. B.H. Salama: None. P. Dogra: None. A.P. Dackiw: None. F. Nwariaku: None. A. Islam: None. A. Mehta: None. S.C. Oltmann: None. S. Mirfakhraee: None. T. McKenzie: None. T.R. Foster: None. M. Lyden: None. B.M. Dy: None. I. Bancos: None. Introduction: Patients with mild autonomous cortisol secretion (MACS) are at risk for adrenal insufficiency (AI) after unilateral adrenalectomy. We aimed to determine the prevalence, predictors, and duration of AI after unilateral adrenalectomy for MACS, and to compare baseline and peak cortisol post cosyntropin stimulation test (CST) in diagnosing AI. Methods: We conducted a dual-center retrospective cohort study of patients with MACS who underwent unilateral adrenalectomy and were evaluated with postoperative cosyntropin stimulation test (CST). AI was diagnosed when postoperative morning cortisol was <10μg/dL and/or CST peak cortisol was <18μg/dL. Baseline and CST peak cortisol levels were considered concordant when both met corresponding cut-offs. Biochemical (BSS) and clinical (CSS) severity scores for hypercortisolism were calculated. Results: In 100 adults with MACS (77% women, median age 56 years, interquartile range [IQR] 48-63), median adenoma size was 2.8 cm (IQR, 2.2-3.7), and 25 (25%) had bilateral nodules. Median BSS was 3 (IQR, 2-5) and median CSS was 4 (IQR, 2-8). After adrenalectomy, AI was diagnosed in 56 (56%) patients. AI was associated with higher BSS, larger tumor size, but not age, sex, BMI, tumor laterality. Baseline and CST peak cortisol levels were concordant in 76% of cases. In 14% of cases morning cortisol was <10μg/dL but CST peak cortisol was ≥18μg/dL, and in 10% of cases morning cortisol was ≥10μg/dL, but CST peak cortisol was <18μg/dL. On a multivariable analysis that included age, sex, BMI, BSS, laterality, and tumor size, only higher BSS (odd ratio [OR] = 1.6 per 1 point) was associated with postoperative baseline cortisol <10μg/dL (P<0.05 for all). Independent predictors of CST peak cortisol <18μg/dL were BSS (OR 1.5 per 1 point) and unilateral adenoma (OR 3.7). During a median postoperative follow up of 13 months, 33 (59%) patients recovered from AI. Median time to recovery was 6.0 months, with AI recovery in 28% of patients by 2 months, 42% by 3 months, 53% by 6 months, and 64% by 12 months. Conclusions: Prevalence of postoperative AI in MACS was 56%. Only 76% of patients had concordant baseline and CST peak cortisol, with peak CST cortisol being more commonly abnormal in patients treated for unilateral MACS. Patients with larger adenomas and higher BSS were at higher risk for AI. Patients with MACS should be counseled about the risk and duration of AI after adrenalectomy. Presentation: 6/3/2024

Abstract Disclosure: J. Hewlett: None. S. Mohan: None. C.J. Davidge-Pitts: None. J. Abeykoon: None. R. Go: None. D.Z. Erickson: None. Objective: Erdheim-Chester Disease (ECD) is a multisystem histiocytic disorder which can infiltrate the pituitary gland, often leading to endocrine dysfunction. Central Arginine Vasopressin Deficiency (cAVP-D) commonly affects ECD patients, and those harboring BRAFV600E are reported to have an increased risk. Insufficient data exist about the risk associated with other mutations, and if cAVP-D or pituitary imaging improves with targeted therapies (TT). Methods: We conducted a review of a prospectively maintained database of adults with ECD treated at a tertiary center between 1992-2023. Objectives of this study were to identify mutations associated with cAVP-D and assess for improvement in cAVP-D (remission of disease or decrease in dose of desmopressin) or pituitary gland involvement (via MRI imaging) following TT for ECD. Results: Of 148 patients with ECD, the majority were male (98, 66.2%) and the mean age at diagnosis was 56.5 years [range: 19-82]. Median length of follow-up was 24 months (95% CI, 17 to 27). Of 121 (81.8%) patients with molecular testing results, 89 (73.6%) harbored a somatic mutation. 67 of 89 (75.3%) carried BRAF mutations, with BRAFV600E in 61 (91.0%) and missense mutations/fusions in 6 (9.0%). 22 of 89 (24.7%) patients harbored other somatic mutations, with MAP2K1 in 13 (14.6%) being the most common. 35 (23.6%) patients were diagnosed with cAVP-D, and the median onset of polyuria and polydipsia prior to diagnosis of ECD was 51 months (95% CI, -120 to -6). Molecular testing was performed in 28 patients with cAVP-D: 17 (60.7%) harbored BRAF mutation and 3 (10.7%) MAP2K1 mutation. There was no significant association between the presence of cAVP-D and MAP2K1 (p=0.69, 95% CI, -0.08 to 0.21). The association between cAVP-D and BRAF did not reach statistical significance (p=0.07, 95%CI, -0.03 to 0.38). Additionally, there was no association between BRAF and timing of cAVP-D symptoms before ECD diagnosis (p=0.08, 95% CI -163.4 to 10.3). Pituitary MRI was available in 32 patients with cAVP-D (91.4%) showing infundibular involvement in 17 (53.1%) and loss of the posterior bright spot in 5 (15.6%). 28 (80%) patients with cAVP-D received systemic therapy, 18 (64.3%) of whom received TT. One patient with cAVP-D was able to discontinue desmopressin. Improvement of pituitary MRI was noted in 7 (21.9%), among whom 4 received TT, 2 received systemic non-TT, and 1 was lost to follow-up. There was no significant MRI improvement associated with TT (p=0.67, 95% CI -0.30 to 0.42). Conclusion: In this large cohort of patients with ECD, of whom the majority underwent molecular testing, we identified no association between MAP2K1 mutation and cAVP-D, and no impact of TT on the clinical course or MRI findings associated with cAVP-D. BRAF mutation carriers were more likely to have cAVP-D and more likely to have onset of symptoms closer to ECD diagnosis, but the results did not reach statistical significance. Presentation: 6/2/2024

Abstract Disclosure: M. Fleseriu: Consulting Fee; Self; Novo Nordisk, Amryt Pharma Holdings Ltd, Ascend Therapeutics (A Besins Healthcare company). Speaker; Self; Xeris Pharmaceuticals, Inc., RECORDATI_RARE_DISEASES_INC., Ipsen Pharma SAS. S.L. Samson: Advisory Board Member; Self; Amryt. Research Investigator; Self; Amryt. N. Biermasz: Advisory Board Member; Self; Recordati, Pfizer Global R&D. Grant Recipient; Self; Macro Registry Grant, Amryt. C.J. Strasburger: Advisory Board Member; Self; Sandoz, Ipsen, Recordati. Consulting Fee; Self; Ascendis, Amryt, Novo Nordisk, Merck, Sandoz, Recordati. Speaker; Self; Ipsen, Novo Nordisk, HRA-Pharma. S. Fuchs Orenbach: Employee; Self; Chiesi Global Rare Diseases. J.A. Crompton: Employee; Self; Chiesi Global Rare Diseases. S. Melmed: Advisory Board Member; Self; Ionis, Crinetics. Consulting Fee; Self; Ipsen. Grant Recipient; Self; Pfizer. Background: Treatment with oral octreotide capsules (OOC) was evaluated in three phase 3 trials (CH-ACM-01, OPTIMAL, MPOWERED) in patients with acromegaly who previously tolerated and responded to the injectable somatostatin receptor ligands (iSRLs) octreotide and lanreotide. Results demonstrated efficacy and safety despite differences in trial design. Pooling data from all three trials can provide further insight into the biochemical response, symptom improvement, and safety profile of OOC. Objective: Analyze the biochemical changes, symptom control, and safety of OOC through a pooled analysis of phase 3 clinical trial datasets. Methods: Patients included were aged ≥18 years with acromegaly and responded biochemically to iSRL therapy before the initiation of OOC (defined as IGF-I <1.3 × ULN and mean integrated GH <2.5 ng/mL for CH-ACM-01 and MPOWERED, and IGF-I ≤1.0 × ULN for OPTIMAL). Data analyzed were from the following periods: baseline until the end of the double-blind placebo-controlled phase of OPTIMAL (36 weeks); the run-in phase of MPOWERED (26 weeks); end of dose escalation (2-5 months; efficacy data) and end of fixed dose phase (up to 7 months, safety data) for CH-ACM-01. Effect of prior iSRL dose was analyzed using a random effects meta-analysis. Symptom severity was scored using the Acromegaly Index of Severity (AIS) tool. Results: Efficacy, symptom, and safety data were available for 318, 194, and 329 patients, respectively. The overall response rate was 65% with no effect of prior iSRL dose (p>0.05). Mean (SD) IGF-I change from baseline was +0.17 (0.32; n=214), +0.19 (0.39; n=81), and +0.22 (0.57; n=23) for patients with baseline IGF-I levels ≤1 × ULN, 1 to <1.3 × ULN, and ≥1.3 × ULN. Twenty percent (16/81) and 35% (8/23) of patients with baseline IGF-I of 1 to <1.3 x ULN and ≥1.3 x ULN shifted to an improved category of response. There was a median decrease of one symptom per patient (p<0.05) and a mean decrease of 0.8 in AIS (p<0.05). The proportion of OOC responders reporting ≤1, 2, or 3 moderate/severe acromegaly symptoms at baseline and month 6 decreased from 56% to 39%, 32% to 20%, and 20% to 12%. At month 6, improvement was seen for all individual symptoms (joint pain, swelling, sweating, fatigue, headache) of moderate/severe grade and was significant for joint pain (36% to 22%) and swelling (15% to 10%) (p<0.02). Most adverse events (AEs) were gastrointestinal (GI) in nature (54%, n=179/329) with a median onset and duration of 15 and 12 days for first reported GI events. Conclusion: Pooled analysis confirms overall maintenance of biochemical control in patients previously responding to iSRL therapy, with decreased symptom burden in OOC responders. OOC was generally well tolerated with no new safety signals. GI-related AEs were largely transient. These results support OOC as a therapeutic option for treating acromegaly. Presentation: 6/3/2024

Abstract Disclosure: C.A. Villavicencio Torres: None. I. Bancos: None. Background: Adrenocortical carcinoma (ACC) is a rare malignancy with an estimated annual incidence of 0.7-2 cases per million per year. Scarce data are available on rare histological variants of ACC. Objective: To describe the clinical presentation and outcomes of patients diagnosed with oncocytic, sarcomatoid and myxoid ACC variants. Methods: Retrospective single center cohort study, 1992-2021 of patients with rare histological ACC variant. Results: A total of 20 patients were diagnosed with oncocytic (17, 85%), sarcomatoid (2, 10%), or myxoid (1, 5%) ACC. Median age of diagnosis was 47 years (range 17-80), and 14 (70%) were women. All patients had unilateral ACC (12, 60% left) with a median tumor size of 11 cm (range 4-29). Adrenal hormone excess was documented in 10 (50%) patients, mostly with either glucocorticoid or androgen excess. ENSAT stage I, II, III, and IV was documented in 2 (10%), 10 (50%), 6 (30%), and 2 (10%) patients, respectively. All patients were treated with adrenalectomy (laparoscopic in 5 and open in 15). In addition, patients were treated with mitotane (10, 50%), radiation (7, 35%), and chemotherapy (5,25%). Mitotane was administered for a median of 12 months (range 4-31) and was discontinued mainly due to side effects in 9 (90%) patients. Patients were followed for a median follow up of 6.5 years (range 0.4-12). In addition to 2 patients who presented with ENSAT stage IV metastatic disease, metastatic disease developed in additional 6 (30%) patients who initially presented with localized ACC (3 stage 2, 3 stage 3, 5 oncocytic, 1 sarcomatoid). Metastatic sites included lung (n=2), omentum (n=1), duodenum (n=1), liver (n=4), and bones (n=1). At the end of follow up, 11 (55%) patients remained disease free (53% oncocytic, 50% sarcomatoid, 100% myxoid), 5 (25%) patients were alive with metastatic ACC (23% oncocytic, 50% sarcomatoid), and 4 patients died of ACC (median time to death 21 months (range 10-50) post-adrenalectomy). Conclusions: Patients with oncocytic, sarcomatoid, and myxoid ACC may have a better prognosis than in reported literature. Larger multicenter studies are needed to identify patient and tumor-specific factors that guide management to assure improved outcomes in these very rare patients. Presentation: 6/2/2024

Abstract Disclosure: K. Leopold: None. S. Polites: None. L. Binkovitz: None. L. Casas: None. A.N. Lteif: None. Title: An Unexpected Cause of Ga-68 Dotatate PET/CT Somatostatin Receptor Avidity in a Pediatric Patient with Hereditary Paraganglioma-Pheochromocytoma Syndrome due to an SDHA Mutation. Introduction: Individuals with Succinate Dehydrogenase (SDHx) gene mutations have an increased risk of paragangliomas and pheochromocytomas beginning in childhood.Clinical Case: A 9 year old male with Cornelia de Lange syndrome and a paternally inherited SDHA pathogenic gene variant (c1534C>T) presented with worsening migraine headaches and skin pallor with activity. 24 hour urine fractionated metanephrines were mildly elevated, with metanephrine 122 mcg/24h (29-92 mcg/24 h), normetanephrine 187 mcg/24 h (34-169 mcg/24 h), and total metanephrine 309 mcg/24 h (47-223 mcg/24 h). Ga-68 DOTATATE PET/CT showed a focus of moderately increased radiotracer activity in the anterior aspect of the distal gastric antrum with a max SUV 8.2 corresponding to a 9x7 mm nodule on CT in the same area, suggestive of underlying somatostatin receptor positive lesion such as a paraganglioma. MRI with contrast completed to further characterize the lesion showed no visible mass corresponding to the focal area of radiotracer uptake on DOTATATE PET/CT. Repeat 24 h urine metanephrines continued to show mild elevation of metanephrine (138 mcg/24h), normetanephrine (200 mcg/24h), and total metanephrines (338 mcg/24h). 24 hour urine catecholamines, 5-Hydroxyindoleacetic acid, and homovanillic acid were normal. An upper endoscopic ultrasound was completed which confirmed the presence of a lesion near the stomach but not arising from the stomach wall and not consistent with a gastrointestinal stromal tumor. CT enterography with IV contrast showed a 6x6 mm enhancing mass within the distal right lateral gastric wall. Due to ongoing symptoms, mild elevations in urine fractionated metanephrines, and a clear mass on US and CT, the patient underwent laparoscopic abdominal exploration where a 14x14x13 mm mass with surrounding gastric and duodenal serosa was excised with primary closure of the bowel. Pathology showed ectopic pancreatic tissue in the wall of the small bowel and stomach. Repeat Ga-68 DOTATATE PET/CT 5 months following surgery showed resolution of the distal gastric somatostatin receptor avidity. Clinical Lesson: This is the first case of ectopic pancreatic tissue mimicking a paraganglioma in a pediatric patient with hereditary paraganglioma-pheochromocytoma syndrome. False positive imaging should be considered in patients with SDHx mutations when the uptake is atypical in location and when the elevation in urine metanephrines is mild. Presentation: 6/3/2024

Abstract Disclosure: M. Moazzami: None. N. Venkatesan: None. K.S. Rajagopalan: None. A.V. Vella: None. A. Egan: None. Gestational diabetes mellitus (GDM) affects approximately 10% of pregnancies, with rates almost doubling in minority subgroups. Higher body mass index (BMI) is a significant GDM risk factor, and BMI ≥ 25kg/m2 is often used as a criterion in risk factor-based screening programs. However, up to 60% of individuals with GDM have a normal BMI, and it is unclear if this offers protection against associated adverse outcomes. Furthermore, many prior studies fail to address the fact that those of Asian descent require a lower BMI cut-off, given their different distribution of body fat. Our study evaluated GDM pregnancy outcomes using BMI as a risk indicator. We compared individuals with BMIs < 25 kg/m2, 25-30 kg/m2, and > 30 kg/m2. For individuals that self-identified as Asian, we adjusted BMI categories: <23 kg/m2 for normal weight, 23-30 kg/m2 for overweight, and >30 kg/m2 for obese. We identified 2212 subjects diagnosed with GDM via universal screening and Carpenter and Coustan criteria at our institution from 2018 - 22. In total, 508 (23.0%) were normal weight, 611 (27.6%) overweight, and 1093 (49.4%) obese. The average maternal age was 31 years. Higher proportions identified as Hispanic and non-White race in overweight and obese categories. Maternal adverse outcomes were higher in obese compared to overweight or normal BMI categories (cesarian delivery: normal 26.7 v overweight 28.3 v obese 22.7%, p<0.001; hypertensive disorders: normal 13.2 v overweight 12.5 v obese 22.7%, p <0.001). Pharmacological therapy was required in 50% with obesity versus 24.8% in normal, and 28.7% in overweight categories (p<0.001). While there were no differences in live birth rates across categories, infants born to mothers with obesity had a higher birthweight (normal 3.30 v overweight 3.38 v obese 3.45kg, p<0.001) and were more likely to have neonatal hypoglycemia (normal 28.7 v overweight 25.5 v obese 43.8%, p<0.001) and require intensive care unit admission (normal 8.4 v overweight 5.5 v obese 12.7%, p<0.001). Attendance at postpartum glucose testing varied across BMI categories with lower attendance in mothers with obesity followed by normal weight BMI (normal 40.75 v overweight 45.99 v obese 36.2%, p<0.001). Compared to overweight individuals, those with normal weight exhibited higher rates of postpartum glucose intolerance (12.4 v 6.9%, p =0.002). However, those with obesity had the highest rates of glucose intolerance (20.7%, p<0.0002). Individuals with normal weight had the highest rates of breastfeeding (normal 95.9 v overweight 92.8 v obese 91.4% p=0.006). This study highlights the nuanced relationship between BMI and pregnancy outcomes in GDM. While maternal obesity was associated with the poorest outcomes, those with normal BMI were not protected compared to overweight individuals, and experience higher rates of postpartum glucose intolerance. Presentation: 6/2/2024

Abstract Disclosure: A.J. Han: None. S.J. Achenbach: None. B.J. Atkinson: None. I. Bancos: None. Background: Diagnosis of adrenal insufficiency (AI) is often delayed due to its vague and non-specific symptomatology. As classic symptoms of AI such as fatigue and nausea are prevalent in the general population, identifying clinical features that are more specific to AI may help clinicians determine which patients require additional testing. Methods: A single-center retrospective study was performed of patients who underwent outpatient Cosyntropin stimulation testing (CST) between 2005-2018. Patients with oral glucocorticoid or estrogen use within 2 months of CST, and patients without available Current Visit Information (CVI) form at the time of CST were excluded. Presence of symptoms was obtained from CVI, and laboratory findings were electronically extracted. Adrenal insufficiency was defined as post-CST peak cortisol <18 mcg/dL. Morbidity was assessed using the Elixhauser index. Variables for multivariable analysis were defined a priori and included fatigue, dizziness, muscle pain, joint pain, weight loss >10 pounds, abdominal pain, nausea/vomiting, and hyponatremia. Results: Among 5347 patients who underwent CST, 376 (7.0%) of patients were found to have AI. There were no sex differences between patients with and without AI, however patients with AI were slightly older (median age 48.9 vs 47.1 years, p=0.026), and had a higher median BMI (26.5 vs 25.6 kg/m2, p=0.002). Prevalence of comorbidities was similar between the two groups, with a median Elixhauser index of 1 (IQR 1-3), however, patients with AI were more likely to report difficulties with activities of daily living (69% vs 57%, p<0.001). Hyponatremia was diagnosed in 4% of patients with AI and 3% of those without AI, p=0.208. Although patients in our cohort reported a high prevalence of fatigue (79%), dizziness (50%), joint pain (50%), muscle pain (48%), nausea (40%), abdominal pain (39%), and weight loss in the past 6 months (29%), there were no statistically significant differences in reported symptoms between patients with and without AI with the exception of joint pain (59% vs 49%, p<0.001) and muscle pain (54% vs 47%, p=0.009). Based on multivariable analysis, only joint pain (OR 1.51, 95% CI 1.14-1.99) and weight loss >10 pounds in the past 6 months (OR 1.31, 95% CI 1.02-1.68) were associated with higher odds of AI diagnosis. Interestingly, patients who reported fatigue had lower odds of AI diagnosis on CST (OR 0.66, 95% CI 0.49-0.88). Conclusions: Commonly associated symptoms of AI such as fatigue, dizziness, nausea, and abdominal pain were poor predictors of AI diagnosis based on CST. Consequently, the presence of these symptoms alone may not warrant additional testing. Notably, clinical features such as myalgia, arthralgia, and weight loss >10 pounds in the past 6 months were found to be more predictive of AI. Presentation: 6/1/2024

Abstract Disclosure: N. Safwan: None. E.R. Uddenberg: None. M.D. Hurtado: None. M. Saadedine: None. S.S. Faubion: None. O. Obrutu: None. S.L. Berga: None. M.D. Pisarska: None. C. Bairey Merz: None. C.L. Shufelt: None. Background: Functional hypothalamic amenorrhea (FHA) accounts for 30% of secondary amenorrhea due to suppression of GnRH associated hypercortisolemia resulting in chronic hypoestrogenemia. FHA occurs as a result of varying combinations of psychosocial stress, excessive exercise, and/or disordered eating. FHA is associated with decreased bone mineralization; however, it is unknown how bone health compares to older, menopausal women who also experience bone loss. We compared dual-energy x-ray absorptiometry (DXA) bone health parameters among women with FHA, eumenorrheic controls, and recently menopausal women and evaluated if previous oral contraceptive (OC) use among FHA women has an impact on bone mineral density (BMD). Methods: This cross-sectional study included 20 women with FHA, 9 eumenorrheic controls, and 12 recently menopausal women who underwent hip and spine DXA. All participants were not on hormone therapy. FHA was defined as amenorrhea >3 consecutive months, estradiol <50 pg/ml, FSH <10 mIU/L, and LH <10 mIU/L, excluding other etiologies including PCOS, prolactinoma, thyroid dysfunction, and pregnancy. Eumenorrheic controls had self-reported monthly menses confirmed with day 22-24 progesterone >3 ng/ml. Recently menopausal women had natural menopause <3 years of final menstrual period, and FSH >30 mIU/L. DXA bone health parameters were measured using Lunar iDXA (GE) including BMD from the lumbar spine (L1-L4) and hip. Statistical analysis included nonparametric testing with pairwise Wilcoxon rank sum and Kruskal Wallis, reported as median [interquartile ranges]. Results: By design, the mean age of FHA was 28 ± 6 yr, 29 ± 3 yr for controls, and 54 ± 2 yr for recently menopausal women (p<0.0001). There were no differences in weight or BMI among the groups (p=0.27, p=0.30, respectively). BMD L1-L4 differed among the three groups with 1.10 g/cm2 [1.00, 1.24] for FHA, 1.18 [1.15, 1.29] for eumenorrheic controls, and 1.02 [0.96, 1.08] for menopausal women (p=0.002). Pairwise analysis revealed a significant difference in BMD L1-L4 between FHA and controls (p=0.04) and menopausal women and controls (p=0.009, age-adjusted). However, there was no difference in BMD L1-L4 between FHA and menopausal women (p=0.08, age-adjusted). In FHA women with previous OC use, BMD L1-L4 was not different from eumenorrheic controls (p=0.20), while BMD L1-L4 differed from that of recently menopausal women (p=0.004). These differences were not observed at the hip. Conclusion: Compared to eumenorrheic controls, lumbar spine BMD in young women with FHA (mean age 28 yr) was similar to recently menopausal women (mean age 54 yr) emphasizing the profound bone impact of FHA. Previous OC use seems to mitigate FHA bone mineralization changes. Future studies should investigate if bone health differs among women with FHA based on underlying cause and if previous OC use plays a role in maintaining bone health. Presentation: 6/3/2024