SAT181 Clinical Profile And Treatment Outcomes Of Patients With Sporadic And Multiple Endocrine Neoplasia Syndrome-related Primary Hyperparathyroidism

Disclosure: U.E. Mathew: None. V.P. Jyotsna: None. A.S. Upadhyay: None. A. Goyal: None. D. Kandaswamy: None. C. Bal: None. A. Sharma: None. C.K. Sharma: None. S. Aggarwal: None. N. Tandon: None. Primary hyperparathyroidism (PHPT) is the most frequent endocrine disorder in MEN-1. The MEN-1 related PHPT (MPHPT) differs from sporadic (SPHPT) in many aspects. The distinction between them is very important at the point of diagnosis as it enables planning on treatment and subsequent surveillance for other endocrine tumours. Objective: The aim of study was to compare the clinical, biochemical, radiological features and surgical outcome in patients with MPHPT versus SPHPT and to identify the predictors of MEN-1 among apparently sporadic hyperparathyroidism. Design: Ambispective cross-sectional study from 2015-2021. Participants: 251 subjects with SPHPT and 23 subjects with MPHPT. Setting: The endocrine clinic of All India Institute of Medical Sciences, New Delhi, India. Results: The classical symptoms of hyperparathyroidism (80.5% vs 47.8%, p<0.001), mean serum calcium (12.7 vs 11.8 mg/dl, p=0.01) and alkaline phosphatase (ALP) levels (p=0.03) were significantly seen higher in SPHPT than MPHPT. MEN-1 patients showed low bone mineral density (BMD) at lumbar spine (-1.52±1.44 vs -2.6±1.25, p=0.001) and femoral neck (1.13±1.37 vs-1.81±1.01, p=0.002) and higher prevalence of complicated nephrolithiasis (34.5 % vs 56.5%, p=0.03) for the age. BMD at their lumbar spine showed an inverse correlation with serum PTH (r=-0.51, p=0.01). Whereas the typical radiological features of hyperparathyroidism and severe skeletal manifestations including brown tumours and fractures were observed less in MEN-1 (44.8% vs 21.7% vs, p=0.02). The overall remission rate was 98.6% in SPHPT and 90% in MPHPT on long term follow up.Despite milder biochemical features, the frequency of hungry bone syndrome was not different from SPHPT (11.6% vs 15.8%, p=0.32). The transient and permanent hypoparathyroidism were more common in MPHPT group (24.4% vs 50%, p=0.01: 0.4% vs 15%, p=0.002).The factors strongly predictive of MEN-1 in multivariate analysis were ALP within the normal range (OR 4.2(95% CI 1.1-16.9), p=0.038), lower lumbar spine BMD (OR 0.47 (95% CI (0.28-0.76), p=0.003) and hyperplastic parathyroid gland on histopathology (OR 37.1(95% CI (9.9-138.6), p<0.001). The multivariate predictive model showed an excellent discrimination between two classes with area under curve in ROC was 0.91. Conclusions: MEN-1 associated PHPT have severe bone and renal involvement despite milder biochemical features, even in Indian settings, where there is a higher frequency of severe symptomatic sporadic hyperparathyroidism. MEN-1 should be suspected when, a discordant finding of severe degree of bone demineralisation at lumbar spine and in normal range of ALP, has observed among apparently SPHPT. Our model can assist in deciding on screening for MEN-1 as the family history and multiglandular involvement may be absent at the presentation, and delay in development of other endocrine tumours. Presentation: Saturday, June 17, 2023