Intact parathyroid hormone (iPTH) levels in the 150 to 450 pg/mL range may confer the lowest risks for all-cause and cardiovascular mortality among patients initiating hemodialysis (HD), according to investigators.
Citing the controversy surrounding this topic and disparate guideline recommendations, Yang Luo, MD, PhD, and colleagues from Beijing Shijitan Hospital, Capital Medical University, in Beijing, China, reported on their study examining mortality risk according to iPTH categories defined in guidelines developed by the Kidney Disease Outcomes Quality Initiative (KDOQI): iPTH less than 150, 150-300, and more than 300 pg/mL.
Over a median 58 months, 157 of 346 patients with incident HD (45.4%) died, including 109 from cardiovascular causes and 25 from infection. An adjusted multivariate Cox regression analysis showed that iPTH less than 150 pg/mL and greater than 300 pg/mL were significantly associated with 4.0- and 1.7-fold greater risk for all-cause mortality and 4.7- and 1.9-fold greater risk for cardiovascular mortality, respectively, compared with an iPTH level of 150 to 300 pg/mL (reference), Dr Luo’s team reported in Renal Failure.
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The investigators then performed a sensitivity analysis stratifying serum iPTH into 6 groups. An adjusted multivariate Cox regression analysis showed that patients with serum iPTH of 750 or more, 600-749, and 450-599 pg/mL had significant 5.0-, 3.6-, and 3.5-fold greater risk of all-cause mortality and 11.7-, 6.8-, and 7.2-fold greater risk of cardiovascular mortality compared with patients with the reference value. Patients with iPTH 300-449 pg/mL did not have significantly different death risks.
“The association between serum iPTH and mortality shows a U-shaped curve,” Dr Luo and colleagues stated. “The optimal serum iPTH level which confers the lowest risk of all-cause and cardiovascular mortality could range from 150 pg/mL to 450 pg/mL in this group of incident HD patients.”
The investigators noted that this iPTH range is narrower than maintaining iPTH at 2 to 9 times the upper normal limit as recommended by the latest Kidney Disease Improving Global Outcomes (KDIGO) guideline.
Serum phosphorus exceeding 1.78 mmol/L and serum calcium less than 2.10 mmol/L also significantly correlated with greater death risks. The investigators did not assess other biochemical markers related to chronic kidney disease-mineral and bone disorder, such as fibroblast growth factor-23, which is a study limitation.
Reference
Zhou X, Guo Y, Luo Y. The optimal range of serum intact parathyroid hormone for a lower risk of mortality in the incident hemodialysis patients. Ren Fail. 43(1):599-605. doi:10.1080/0886022X.2021.1903927
