PTH and Hypocalcemia: Table 2 shows the proportion of temporary and long-term PoSH in different groups of patients classified into various patient-, provider- and surgery-related factors. Day one hypocalcaemia (adjusted calcium of <2.1mmol/L) was associated with low PTH on the first postoperative day (p < 0.001) and the drop in perioperative PTH (p < 0.001). In addition, PoSH at 6 months was also associated with low PTH on the first postoperative day (p < 0.001) and drop in perioperative PTH (p < 0.001).