Outcomes associated with serum phosphorus level in males with non-dialysis dependent chronic kidney disease.
OBJECTIVE
Hyperphosphatemia is associated with higher mortality and increased incidence of end-stage renal disease in patients with non-dialysis dependent CKD (NDD-CKD), but there has not been a concomitant assessment of mortality and progressive kidney disease that would also account for cumulative effects of hyperphosphatemia.


METHODS
In order to account for the cumulative effects of abnormal serum phosphorus we examined associations of not only baseline, but also time-averaged serum phosphorus levels with all-cause mortality, the composite of mortality or ESRD and the slopes of estimated glomerular filtration rate (eGFR), by using Cox models and mixed effects models in a contemporary cohort of 713 males with moderate and advanced NDD-CKD.


RESULTS
Higher baseline and time-averaged serum phosphorus were both associated with mortality and with the composite outcome. A 1 mg/dl higher time-averaged serum phosphorus was associated with a multivariable adjusted hazard ratio of all-cause mortality (95% CI) of 1.56 (1.19 - 2.05), p = 0.001. Higher serum phosphorus was associated with a steeper slope of eGFR in unadjusted analyses, but this association became non-significant after multivariable adjustments.


CONCLUSIONS
The cumulative burden of hyperphosphatemia is associated with increased mortality in patients with moderate and advanced NDD-CKD. Clinical trials are needed to determine if lowering serum phosphorus can result in improved mortality in this population.
Kovesdy
C P
CP
Division of Nephrology, Salem Veterans Affairs Medical Center, 1970 Roanoke Blvd., Salem, VA 24153, USA. csaba.kovesdy@va.gov
Anderson
J E
JE
Kalantar-Zadeh
K
K
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003404:Creatinine / Q000097:blood; D006801:Humans; D054559:Hyperphosphatemia / Q000097:blood / Q000401:mortality*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D010758:Phosphorus / Q000097:blood*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016019:Survival Analysis
D010758:Phosphorus; D003404:Creatinine