Original investigation: dialysis therapy
Hyperphosphatemia in Chinese peritoneal dialysis patients with and without residual kidney function: what are the implications?

https://doi.org/10.1053/j.ajkd.2003.12.032Get rights and content

Abstract

Background: Hyperphosphatemia is an important predictor for mortality in hemodialysis patients. This study evaluated significant factors associated with hyperphosphatemia in peritoneal dialysis (PD) patients. Methods: We estimated residual renal function (RRF), dialysis adequacy, and normalized protein equivalent nitrogen appearance (nPNA), together with simultaneous measurement of serum phosphorus levels in 252 prevalent Chinese continuous ambulatory peritoneal dialysis (CAPD) patients. Results: Average serum phosphorus level was 5.2 ± 1.5 mg/dL (1.68 ± 0.48 mmol/L). Serum phosphorus levels were 5.6 mg/dL or greater (≥1.81 mmol/L) in 44.0% of anuric patients (n = 116) versus 28.7% of patients with RRF (n = 136; P = 0.012). Patients with RRF maintained serum phosphorus levels at or less than the median value (≤5.1 mg/dL [≤1.65 mmol/L]), with a total creatinine clearance (CCr) of 72 ± 25 L/wk/1.73 m2 and nPNA of 0.94 ± 0.19 g/kg/d in contrast to a total CCr of 63 ± 22 L/wk/1.73 m2 (P = 0.031) and nPNA of 1.03 ± 0.22 g/kg/d (P = 0.011) in patients with serum phosphorus levels greater than the median value. Among anuric patients, total CCrs were 46 ± 9 and 42 ± 7 L/wk/1.73 m2 (P = 0.005) and nPNA values were 0.89 ± 0.17 and 0.98 ± 0.18 g/kg/d (P = 0.010) for patients with serum phosphorus levels at the median value or less and greater than the median value, respectively. Multiple regression analysis showed that residual glomerular filtration, despite an average of less than 2 mL/min/1.73 m2, was independently associated with phosphorus control in PD patients. nPNA, PD CCr or urea clearance, body mass index, and parathyroid hormone level were other important correlates of serum phosphorus levels in patients with and without RRF. Conclusion: Hyperphosphatemia is a frequent complication in Chinese CAPD patients. Our study not only shows the importance of RRF in maintaining serum phosphorus levels in PD patients, but also the limitations of PD alone to achieve adequate phosphorus control in anuric patients.

Section snippets

Methods

Two hundred fifty-two patients receiving CAPD treatment for 3 months or more were recruited from our total PD patient pool of 270 at the Prince of Wales Hospital in Hong Kong. All patients were dialyzed using glucose-based lactate-buffered PD solutions. Eighteen patients were excluded based on the following exclusion criteria: namely, patients with underlying malignancy, chronic liver disease, chronic obstructive airway disease, systemic lupus erythematosus, and active tuberculous infection

Results

The frequency distribution of serum phosphorus levels of our PD patients followed a normal bell-shaped curve, with a mean of 5.2 ± 1.5 mg/dL (1.68 ± 0.47 mmol/L) and median of 5.1 mg/dL (1.64 mmol/L; lab reference range, 2.5 to 4.3 mg/dL [0.82 to 1.40 mmol/L]). Serum phosphorus levels were 5.6 mg/dL or greater (≥1.8 mmol/L) in 90 patients (35.7%), among whom 47 patients (52.2%) had serum phosphorus levels greater than 6.5 mg/dL (>2.1 mmol/L). Serum phosphorus levels were 5.6 to 6.5 mg/dL or

Discussion

To our knowledge, this is the first study that examines phosphorus control with simultaneous consideration of renal and dialysis clearance, as well as nutrition status, in Chinese CAPD patients. Previous surveys indicated that more than half the hemodialysis patients had serum phosphorus levels greater than 5.9 mg/dL (>1.9 mmol/L).1, 18 Although continuous PD is taken to be better in controlling hyperphosphatemia than intermittent hemodialysis,19 our current survey shows that hyperphosphatemia

References (34)

  • M. Sedlacek et al.

    Relationship between phosphorus and creatinine clearance in peritoneal dialysisClinical implications

    Am J Kidney Dis

    (2000)
  • J. Uribarri

    DOQI guidelines for nutrition in long-term peritoneal dialysis patientsA dissenting view

    Am J Kidney Dis

    (2001)
  • M. Boaz et al.

    Regression equation predicts dietary phosphorus intake from estimate of dietary protein intake

    J Am Diet Assoc

    (1996)
  • J. Bergstrom et al.

    Protein and energy intake, nitrogen balance and nitrogen losses in patients treated with continuous ambulatory peritoneal dialysis

    Kidney Int

    (1993)
  • M.J. Blumenkrantz et al.

    Metabolic balance studies and dietary protein requirements in patients undergoing continuous ambulatory peritoneal dialysis

    Kidney Int

    (1982)
  • N.W. Levin et al.

    Which causes of death are related to hyperphosphatemia in hemodialysis (HD) patients?

    J Am Soc Nephrol

    (1998)
  • F. Llach

    Cardiac calcificationDealing with another risk factor in patients with kidney failure

    Semin Dial

    (1999)
  • Cited by (76)

    • Volume Management With Peritoneal Dialysis

      2022, Handbook of Dialysis Therapy
    • EOS789, a broad-spectrum inhibitor of phosphate transport, is safe with an indication of efficacy in a phase 1b randomized crossover trial in hemodialysis patients

      2021, Kidney International
      Citation Excerpt :

      Although many dialysis patients are anuric, some patients, especially those on peritoneal dialysis, retain residual renal function. Wang et al. demonstrated that anuric patients undergoing peritoneal dialysis had elevated serum P levels nearly twice as often as patients with residual renal function.28 The removal of P with dialysis varies considerably and is affected by blood flow, dialysis duration, predialysis serum P, PTH level, and ultrafiltration volume.29,30

    • Strategies for Phosphate Control in Patients With CKD

      2019, Kidney International Reports
      Citation Excerpt :

      It occurs already in early stages of the disease. From a histologic point of view, renal osteodystrophy comprises high-turnover (osteitis fibrosa and mixed renal osteodystrophy) at later CKD stages and low-turnover bone disease (adynamic osteopathy) at early and later CKD stages.125,126 Both types may contribute to hyperphosphatemia, either by increasing bone resorption and phosphate release, or by reducing bone formation and phosphate uptake.

    • Peritoneal Dialysis Solutions, Prescription and Adequacy

      2018, Chronic Kidney Disease, Dialysis, and Transplantation: A Companion to Brenner and Rector’s The Kidney
    • Evaluation of a mineral metabolism protocol in peritoneal dialysis patients

      2014, Journal of Renal Nutrition
      Citation Excerpt :

      The United States Renal Data System Case Mix Adequacy and the Dialysis Morbidity and Mortality Wave II studies demonstrated that approximately 53% of HD (n = 6,407) patients had serum phosphorus levels above the range of 5.9 mg/dL (1.9 mmol/L).1 In a cross-sectional study (n = 252), Wang et al.2 found that the serum phosphorus levels were greater than 5.6 mg/dL (1.8 mmol/L) in more than 35.7% (n = 90) of PD patients with more than 50% (n = 47) of them having a level of 6.5 mg/dL (2.1 mmol/L) or greater. To address the issue of altered mineral metabolism in patients on peritoneal dialysis, current practice is to aim for set target ranges for serum phosphorus, calcium, and iPTH.

    View all citing articles on Scopus

    Supported in part by the Bristol Myers Squibb Foundation Nutrition Grant Program and the Hong Kong Health Service Research Fund.

    View full text