High-normal serum phosphate levels appear to increase the risks of acute kidney injury (AKI), end-stage renal disease (ESRD), and mortality in hospitalized patients, according to new study findings.
Of 20,686 adults admitted to Seoul National University Bundang Hospital in South Korea during 2013, AKI developed in 2319 (11.2%). Patients grouped in the third (3.64 mg/dL) and fourth (4.38 mg/dL) quartiles of serum phosphate at admission had 1.4- and 1.6-fold higher risks of AKI compared with those in the first quartile (reference), regardless of their estimated glomerular filtration rate (eGFR), Seung Seok Han, MD, PhD, of Seoul National University College of Medicine, and colleagues reported in BMC Nephrology.
During a median follow-up of 4.0 years, ESRD developed in 183 patients (0.88%) and 3675 patients (17.8%) died. Compared with the reference group, those in the fourth quartile overall had a significant 2.3-fold increased risk of ESRD. Among patients with an eGFR of 60 mL/min/1.73 m2 or higher, patients in the fourth quartile had a significant 5.2-fold increased risk of ESRD compared those in the first quartile. Investigators observed no significant association between serum phosphate quartile and ESRD risk among patients with a lower eGFR.
Overall, patients in the fourth quartile had a significant 1.3-fold increased risk of mortality compared with the reference group. Among patients with an eGFR of 60 mL/min/1.73 m2 or higher, those in the fourth quartile had a significant 1.3-fold increased risk of death compared with the reference group; among those with a lower eGFR, those in the fourth quartile had a significant 1.4-fold increased risk of death compared with the reference group.
Serum phosphorus monitoring may help to identify patients at high risk of kidney function deterioration or mortality, Dr Han’s team stated.
Moon H, Chin HJ, Na KY, et al. Hyperphosphatemia and risks of acute kidney injury, end-stage renal disease, and mortality in hospitalized patients. BMC Nephrol. 2019;20:362. doi: 10.1186/s12882-019-1556-y