Hyperphosphatemia-Related Mortality Is Modified by Serum Albumin and Creatinine Levels in Hemodialysis Patients: The Q-Cohort Study.

OBJECTIVE

Hyperphosphatemia is a well-established predictor of mortality in hemodialysis patients. However, its impact may vary depending on clinical conditions. We examined whether serum albumin and creatinine (Cr) levels modify the association between hyperphosphatemia and mortality.

DESIGN AND

METHODS

We conducted a prospective, multicenter cohort study involving 3,050 patients on maintenance hemodialysis, followed for up to 4 years. The primary outcomes were all-cause and cardiovascular mortality. Serum phosphorus levels were the main exposure; serum albumin and Cr levels were evaluated as potential effect modifiers. Sensitivity analyses were performed using the Geriatric Nutritional Risk Index and modified creatinine index. Cox proportional hazards models were used to assess mortality risk.

RESULTS

Over a median follow-up of 3.5 years, 639 patients died, including 227 from cardiovascular causes. In multivariable-adjusted models, hyperphosphatemia was significantly associated with higher risks of both all-cause and cardiovascular mortality. Stratified analyses revealed that this association was significant only in patients with higher serum albumin or lower Cr levels. Among patients with lower albumin or higher Cr, the association was not significant. Significant interaction effects were observed between serum phosphorus and both albumin and Cr, highlighting a potential modifying role of nutritional and muscular status in phosphate-related mortality risk. In sensitivity analyses, similar patterns were observed, with the association between hyperphosphatemia and mortality being more evident among patients with higher Geriatric Nutritional Risk Index and lower modified creatinine index.

CONCLUSION

The prognostic impact of hyperphosphatemia may differ according to serum albumin and Cr levels in patients undergoing hemodialysis.