The following is a summary of “Relationship between serum phosphorus and mortality in non-dialysis chronic kidney disease patients: evidence from NHANES 2001–2018” published in March 2024, issue of Nephrology by Fan et al.

Hyperphosphatemia is common in Chronic Kidney Disease (CKD) as it spells higher mortality for dialysis patients. Yet its threat to non-dialysis patients, with maintained kidney function, remains shrouded in uncertainty.

Researchers conducted a prospective study to understand the impact of serum phosphorus on patients with CKD, especially with non dialysis and preserved kidney function patients.

They used data from the National Health and Nutrition Examination Survey (2001-2008). Serum phosphorus levels were analyzed continuously or categorized (<3.5 mg/dL, 3.5 to 4.5 mg/dL, ≥4.5 mg/dL). Cox proportional hazards models assessed associations between phosphorus levels and all-cause/CVD mortality, adjusting for various factors.

The result studied 7694 participants who were representing 28 million CKD patients in the US, 2708 all cause deaths (including 969 CVD deaths) occurred during a mean 92 months. Each 1 mg/dL increase in phosphorus correlated with 13% (HR, 1.13; 95%CI, 1.02–1.24) increased risks of all-cause and 24% (HR, 1.24; 95%CI, 1.07-1.45) increased CVD mortality risk. Elevated phosphorus (≥4.5 mg/dL) significantly associated with higher risks of all-cause and CVD mortality compared to <3.5 mg/dL. In participants with eGFR <60 ml/min/1.73m ² elevated phosphorus was significantly associated with increased all-cause mortality (HR, 1.36; 95%CI, 1.07-1.72).. No significant association was found in the eGFR ≥60 ml/min/1.73m²  group, with no significant difference by eGFR level.

Investigators concluded that, serum phosphorus levels exceeding 4.5 mg/dL exhibit a substantial 28% and 57% elevation in the risk of all-cause and CVD mortality, respectively, among non-dialysis CKD patients; however, additional confirmation is warranted for individuals with eGFR ≥ 60 ml/min/1.73m ².

Source: bmcnephrol.biomedcentral.com/articles/10.1186/s12882-024-03525-x