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

Abstract

Background: Serum phosphorus (SP) level is closely associated with overall mortality and cardiovascular events, while the role of SP controlled duration is not fully recognized. Here, we conducted a retrospective cohort study in our department to identify the relationship of SP controlled duration with clinical outcomes in patients undergoing peritoneal dialysis (PD). Methods: PD patients in our center from January 1, 2009, to June 30, 2019, were followed up at 2-month (the first year) or 5-month (the next follow-up period) intervals, and until death, until PD withdrawal, or until June 30, 2019. Data at each follow-up point were collected from their medical records. SP levels, changed degree of SP over baseline, and SP controlled duration were analyzed with overall mortality, PD withdrawal (including death, transferred to hemodialysis, and received renal transplantation), and combined endpoint (including death, acute heart failure, cardiovascular event, and stroke). Results: A total of 530 patients entered the analysis. Of them, 456 (86.0%) had hyperphosphatemia before dialysis, and the SP levels decreased soon after dialysis. The degree of SP change over baseline was the maximum at the 3rd month after dialysis (−31.0%), and lower degree was associated with higher overall mortality (hazard ratio [HR], 1.012; 95% CI, 1.004-1.020; p = 0.003). The median SP controlled duration was 13 (5-28) months, and longer duration was significantly associated with lower overall mortality (HR, 0.968; 95% CI, 0.956-0.981; p < 0.001). After categorization, duration more than 12 months greatly improved overall mortality with a HR of 0.197 (0.082-0.458; p < 0.001 vs. SP never controlled group) and 0.329 (0.150-0.724; p = 0.006 vs. duration <12 months group). Longer SP controlled duration also improved PD withdrawal and combined endpoint. Conclusions: In summary, both degree and duration of SP control were tightly associated with overall mortality. We should control SP levels as early, as possible, and as long as we could.

Risk factors for mortality within 6 mo in patients with diabetes undergoing urgent-start peritoneal dialysis: A multicenter retrospective cohort study

“…Serum phosphate level has also been found to be a powerful independent predictor of coronary heart disease in patients with diabetes[ 28 ]. Baseline serum phosphorus level was not a risk factor for mortality after 6 mo, which is similar to findings in other studies[ 30 , 31 ]. In our study, we focused on the risk factors for mortality within the first 6 mo; therefore, we only collected the baseline serum phosphorus levels.…”

Management of serum phosphorus over a 1-year follow-up in patients on peritoneal dialysis prescribed sucroferric oxyhydroxide as part of routine care: a retrospective analysis

“…Although the present study does not provide outcomes data, prior evidence has demonstrated that longer durations of sP control were independently associated with reduced mortality—a 3.2% decrease in risk for each additional month of sP control and a 38.1% decrease in risk for each additional year of sP control [ 21 ]. In that same study, a longer duration of sP control was also independently associated with lower rates of PD withdrawal.…”

Serum Phosphorus Management with Sucroferric Oxyhydroxide as a First-Line Phosphate Binder within the First Year of Hemodialysis

“…When considering therapies to lower sP in ESKD, the need for long-term control is paramount. Gong and colleagues found a 3.2% reduced risk of mortality for each month of phosphorus control [ 28 ]. Such data highlight the need for early and prolonged reduction of sP.…”