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Abstract: PO1260

Duration of Serum Phosphorus Control Associated with Overall Mortality in Patients Undergoing Peritoneal Dialysis

Session Information

Category: Dialysis

  • 703 Dialysis: Peritoneal Dialysis

Authors

  • Ai, Jun, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
  • Xiao, Zhiwen, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
Background

Serum phosphorus (SP) level was closely associated with overall mortality and cardiovascular events, while the role of SP controlled duration was not fully recognized. Our study is to identify the relationships of SP controlled duration with clinical outcomes in patients undergoing peritoneal dialysis (PD).

Methods

This was a retrospective cohort study, including PD patients with regular follow-up in our center from Jan 1st, 2009 to Jun 30th, 2019. Clinical data were collected at baseline and at 3, 6, 9, 12, 18, 24, 30, 36, 48, 72, 96, and 120 months after dialysis. SP levels, changed degree of SP over baseline, and SP controlled duration were analyzed with overall mortality, PD withdrawal, and combined endpoint. Degree of SP change over baseline (%) = (SP level at following-up point - baseline SP level) × 100 / baseline SP level. Duration of SP control (months) = PD vintage when patients reached hyperphosphatemia - PD vintage when patients’ SP decreased to less than 1.78 mmol/L after PD.

Results

530 patients entered the analysis [the mean age was 45.4 ± 15.0-year-old, 57.2% were male, the median PD vintage were 32 (15-54) months]. 86.0% patients had hyperphosphatemia before dialysis, and the SP levels decreased soon after dialysis. Degree of SP change over baseline was the maximum at the 3rd month after dialysis (-31.0%), lower degree was associated with higher overall mortality [HR, 1.012(1.004-1.020); p=0.003]. The median SP controlled duration were 13 (5-28) months, the longer SP controlled duration, the lower overall mortality [HR, 0.968(0.956-0.981); p < 0.001], the lower incidence of PD withdrawal [HR, 0.964(0.954-0.973); p < 0.001] and combined endpoint [HR, 0.982(0.976-0.989); p < 0.001]. After categorized, patients whose SP never controlled had the maximum overall mortality (24.6%), the duration more than 12 months greatly improved the overall mortality [HR 0.197 (0.082-0.458); p < 0.001]. Phosphorus binders (PB) applying was significantly associated with overall mortality [HR 0.555(0.332-0.927); p=0.025] and PD withdrawal [HR, 0.523(0.391- 0.698); p < 0.001].

Conclusion

In PD patients, the level of SP and the degree of change after dialysis were tightly associated with overall mortality, PD withdrawal and combined endpoint. The longer SP controlled duration, the lower overall mortality. We should controll SP levels as early and as long as possible.