Association between plasma phosphorus and renal outcome: A prospective cohort of patients majorly with glomerulonephritis.

AIM

Studies investigating the association between blood phosphorus and renal outcomes yielded inconsistent results, and studies from Asian population are extremely limited. We initiated the present cohort study, aiming to prospectively examine the association between blood phosphorus and adverse renal outcomes in a prospective chronic kidney disease (CKD) cohort of Chinese patients majorly with glomerulonephritis.

METHODS

A total of 1430 patients were involved in the study. Linear regression analyses were used to assess the relationship between phosphorus and the slope of estimated glomerular filtration rate (eGFR). Cox regression analyses were used to assess the association between phosphorus and composite outcomes, which were defined as the presence of at least one of: eGFR halving, end stage renal disease, or death.

RESULTS

During follow-up for an average of 41.4 months, 196 patients developed composite outcomes. The time-average plasma phosphorus was independently associated with the slope of eGFR (β = -0.18, 95% CI: -4.42 to -2.19, P < 0.001). Each 1 mg/dL increases of baseline and time-average phosphorus were respectively associated with a 1.33 (95% confidence interval (CI): 1.09-1.63; P = 0.005) and 2.79 (95%CI: 2.21-3.52; P < 0.001) fold higher risk of composite outcomes. Compared with participants in the bottom quartile of time-average phosphorus, those in the top quartile were at increased risk of composite outcomes, with a hazard ratio of 6.52 (95% CI: 3.05-13.90; P < 0.001).

CONCLUSION

Plasma phosphorus level is an independent risk factor of adverse renal outcomes in Chinese CKD patients majorly with glomerulonephritis. Compared with baseline value, time-average phosphorus has a stronger relationship with renal prognosis.