Tanaka M et al. (2007) Hypercalcaemia is associated with poor mental health in haemodialysis patients: results from Japan DOPPS. Nephrol Dial Transplant 22: 1658–1664

Depression and depressive symptoms are frequently reported among patients on hemodialysis. Within the hemodialysis population, patients with depressive symptoms are at a higher risk of death and have higher rates of dialysis withdrawal than do those without such symptoms. Few studies have attempted to determine whether there is an association between abnormal mineral metabolism and psychological disorders. Now, Tanaka et al. report a link between hypercalcemia and poor mental health in a population of Japanese patients on hemodialysis.

By pooling data from phases I and II of the Dialysis Outcomes and Practice Patterns Study, the researchers obtained information on serum corrected calcium, phosphorus and intact parathyroid hormone concentrations, and mental health status (as assessed by a questionnaire) for 4,115 Japanese patients. A significant correlation was found between hypercalcemia and mental health score. The 677 (16.5%) patients with a serum corrected calcium level of ≥2.75 mmol/l (≥11 mg/dl) had a significantly lower mean mental health score than did the patients with serum corrected calcium levels of <2.1 mmol/l (<8.4 mg/dl), 2.1–2.55 mmol/l (8.4–10.2 mg/dl) or 2.55–2.75 mmol/l (10.2 mg/dl–11.0 mg/dl; P = 0.04, P = 0.009 and P = 0.003, respectively). The relationship between serum corrected calcium level and mental health score was independent of age, sex, serum albumin and phosphorus concentrations, use of a vitamin D preparation, use of a calcium-containing phosphate binder and history of parathyroidectomy. No associations were found between mental health score and serum phosphorus concentrations or intact parathyroid hormone levels.