Prevalence and Predictors of Primary Hyperparathyroidism Among Patients with Urolithiasis

Urolithiasis may be the only presenting manifestation of primary hyperparathyroidism (PHPT), and early detection of PHPT in such patients may prevent future urolithiasis and other PHPT complications. This study was performed to study the prevalence and predictors of PHPT in patients presenting with urolithiasis.Consecutive patients presenting with urolithiasis were evaluated for clinical and biochemical manifestations of PHPT with serum and urine calcium (Ca), serum intact parathyroid hormone and 25 (OH) vitamin D. We then compared the clinical and biochemical characteristics of PHPT patients presenting with urolithiasis (group A) and without (group B).During the 3-year study period, 381 patients with urolithiasis were seen with a mean age of 38.5 ± 13.9 years. Nineteen of the 381 (5%) patients had histologically proven PHPT (group A). Four patients in group A (21%) and 8 in group B (2%) had nephrocalcinosis (P.0001), multiple stones (≥3), calcific pancreatitis, and neuropsychiatric manifestations were more common in group A (P.0001). Presence of multiple or bilateral stones, and recurrent stone episodes predicted PHPT (odds ratio [OR]: 3.06, confidence interval [CI]: 0.87, 0.7).One out of every 20 patients with urolithiasis had PHPT, which is higher than the prevalence of PHPT in general population. The presence of nephrocalcinosis and multiple, bilateral, and recurrent stone disease increased the risk of PHPT among stone formers.Ca = calcium; CI = confidence interval; iPTH = intact parathyroid hormone; nPHPT = normocalcemic PHPT; OR = odds ratio; PHPT = primary hyperparathyroidism.