Hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT) who have high serum calcium and phosphate levels have greater risks for death than patients with values in the normal range, regardless of their intact parathyroid hormone (iPTH) level, according to new study findings.

In a chronic kidney disease-mineral bone disorder (CKD-MBD) substudy (MBD-5D), investigators grouped 3276 Japanese HD patients with SHPT (median age 62 years; 62% male) by their serum calcium, phosphate, and iPTH levels. The reference value for calcium was 8.5 or higher but less than 9.5 mg/dL; the reference value for phosphate was 4.0 or higher but less than 7.0 mg/dL.

Among patients with iPTH levels of 300 pg/mL or higher, high calcium levels (9.5 mg/dL or more) were significantly associated with approximately 2.0- and 1.8-fold increases risks for all-cause and cardiovascular mortality, respectively, in adjusted analyses, Shinji Asada, MPH, of Kyowa Kirin in Tokyo, and colleagues reported in Clinical and Experimental Nephrology. Among patients with iPTH levels below 300 pg/mL, high calcium levels were significantly associated with approximately 1.6-fold increased risks for both all-cause and cardiovascular mortality.

Compared with the phosphate reference value, high phosphate levels (7 mg/dL or more) were significantly associated with approximately 3.2- and 2.4-fold increased risks for all-cause and cardiovascular mortality, respectively, among patients in the high iPTH group and 1.6-fold increased risk for all-cause mortality in the low iPTH group. The study found no significant association between serum phosphate and cardiovascular mortality in this group.


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Disclosure: This study was supported by Kyowa Kirin Co., Ltd. Please see the original reference for a full list of authors’ disclosures.

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Reference

Asada S, Yokoyama K, Miyakoshi C, et al. Relationship between serum calcium or phosphate levels and mortality stratified by parathyroid hormone level: an analysis from the MBD‑5D study [published online March 31, 2020]. Clin Exp Nephrol. doi: 10.1007/s10157-020-01879-8