Shariq OA, Strajina V, Lyden ML, et al. - As primary hyperparathyroidism has hypercalciuria as an important manifestation that may contribute to the risk of nephrolithiasis, researchers here investigated how parathyroidectomy affects 24-hour urinary calcium (24-hour U _Ca) levels and rates of resolution of hypercalciuria after surgery. They performed a retrospective cohort study of 110 patients. Of these, 84 (76.4%) experienced a ≥ 20% reduction in 24-hour U _Ca level postoperatively. Preoperative 24-hour U _Ca levels showed a linear correlation with the decline in 24-hour U _Ca excretion after surgery such that the degree of improvement could be determined using the following equation: absolute reduction in postoperative 24-hour U _Ca = 0.68 × preoperative 24-hour U _Ca-68. Per findings, the majority of patients with PHPT had reduction in 24-hour U _Ca excretion following parathyroidectomy. In addition, the procedure restored normocalciuria in 79% of patients with hypercalciuria at baseline.