Endocrine Abstracts

Background: The urinary calcium–creatinine clearance ratio (UCCCR) and Calcium excretion index (CEI) are commonly used to differentiate PHPT from familial hypocalciuric hypercalcemia (FHH) and to support surgical decision-making. However, its diagnostic accuracy and predictive value for postoperative outcomes remain uncertain.

Aim: To assess the clinical utility of UCCCR and CaE in managing PHPT and its impact on surgical outcomes in a single-centre cohort.

Methods: A retrospective audit of 28 patients who underwent parathyroid surgery for primary hyperparathyroidism (PHPT) between April 2024 and March 2025 was conducted. Patient demographics, imaging findings, UCCCR & CEI values were correlated with histopathological diagnosis and postoperative biochemical outcomes.

Results: Among 28 patients (median age 70 years; 86% female), 26 (92.9%) had parathyroid adenomas and 2 (7.1%) had hyperplasia. UCCCR values were high in 6 (21.4%), borderline in 12 (42.9%), and low in 10 (35.7%) patients. 17 patients (60.7%) had CEI ≥ 30, while 11 patients (39.3%) had CEI < 30. Patients with adenomas generally demonstrated higher UCCCR & CEI values compared to those without adenomas, clustering above the clinical cutoffs (~0.01) & 30 respectively. Normocalcemia was achieved postoperatively in 25 patients (89.3%), with 1 case of hypocalcemia (3.6%) and 2 cases of persistent hypercalcemia (7.1%). There was no statistically significant difference in median UCCCR & CEI between those achieving normocalcemia and those who did not (P > 0.05). The contingency coefficient between UCCCR and normocalcemia status was 0.103, indicating a very weak association, while CEI showed no association in achieving normocalcemic status.

Conclusion: While UCCCR and CEI demonstrate some association with underlying pathology (parathyroid adenoma vs. others), they are not a reliable standalone predictor of postoperative normocalcemia. Interpretation should be contextualized in conjunction with clinical and imaging data. Larger studies are warranted to refine diagnostic thresholds and assess prognostic utility.