PTH and Hypocalcemia: In patients with preoperative vitamin D levels <10 ng/mL, the rate of biochemical hypocalcemia was significantly higher (74.0% vs. 60.3%, p = 0.045), but the rate of hypoparathyroidism (postoperative PTH < 15 pg/mL) showed no significant difference (54.8% vs. 56.2%, p = 0.89) [28].