UCSF

We aimed to assess the impact of oral calcium supplementation (OCS) on the prevalence of nephrolithiasis among a cohort of patients undergoing surgery for primary hyperparathyroidism (PHPT). There were 339 patients undergoing surgery for PHPT with detailed past medical history data that were analyzed. 73 patients (22%) had a history of nephrolithiasis prior to parathyroid surgery. Nephrolithiasis was more common among men than women (40% vs 15%, P < 0.001), despite the predominance of women (73% of patients) with hyperparathyroidism. 83 patients (25%) used OCS. OCS was associated with a lower prevalence of nephrolithiasis (9.6% vs 25.4% without OCS, P = 0.002). This protective effect included both men and women (rates of nephrolithiasis with and without supplements: men 19% vs 46%, P = 0.027; women 7% vs 17%, P = 0.04). The mechanism for the apparent protective effect of OCS on rates of nephrolithiasis is unclear, and further research is required to elucidate the variable penetrance of nephrolithiasis among PHPT patients.