Original Investigation
Dialysis
Association of Kt/V and Creatinine Clearance With Outcomes in Anuric Peritoneal Dialysis Patients

https://doi.org/10.1053/j.ajkd.2008.05.013Get rights and content

Background

The 2006 Kidney Disease Outcomes Quality Initiative recommended a minimum total Kt/V of 1.7, eliminated creatinine clearance (Ccr) as a target, and recommended the use of ideal body weight to calculate Kt/V. We assessed these recommendations as predictors of outcomes in anuric peritoneal dialysis patients.

Study Design

Retrospective observational study using administrative data.

Setting & Participants

1,432 peritoneal dialysis patients with anuria from January 1, 1994, to January 31, 2005, in a national sample (1,428 with Kt/V, 1,416 with Ccr).

Predictors

Kt/V and Ccr at anuria; Kt/V based on actual body weight and ideal body weight.

Outcomes & Measurements

Association of dialysis adequacy with mortality and time to first hospitalization after anuria assessed by using accelerated failure time models.

Results

293 anuric patients had Kt/V less than 1.7, 366 had Kt/V of 1.7 to 2.0, and 769 had Kt/V greater than 2.0, using actual body weight for calculation. In unadjusted analyses, Kt/V calculated using actual body weight both less than 1.7 (−41.3%; 95% confidence interval [CI], −55.5 to −22.6) and 1.7 to 2.0 (−26.1%; 95% CI, −42.6 to −4.6) were associated with shorter time to mortality. Kt/V calculated using actual body weight less than 1.7 was associated with shorter time to hospitalization (−38.1%; 95% CI, −50.0 to −23.4), but Kt/V calculated using actual body weight of 1.7 to 2.0 was not a significant predictor (−3.3%; 95% CI, −21.1 to 18.6). After adjustment, Kt/V calculated using actual body weight less than 1.7 remained associated with mortality (−25.3%; 95% CI, −41.1 to −4.8) and hospitalization (−33.4%; 95% CI, −47.1 to −16.0). Ccr did not predict mortality. In unadjusted analysis, Ccr was not associated with hospitalization, but after adjustment, Ccr less than 50 L/wk/1.73 m2 was significantly associated with shorter time to hospitalization (−19.9%; 95% CI, −35.0 to −1.3). Kt/V using ideal body weight was not a significant predictor in adjusted models.

Limitations

This study was nonrandomized, with few malnourished patients. In addition, there is a potential for informative censoring for transfer to hemodialysis therapy before anuria.

Conclusions

Kt/V calculated using actual body weight less than 1.7 in anuric peritoneal dialysis patients is associated with increased mortality and hospitalization. Use of ideal body weight to calculate Kt/V weakened the associations with outcomes and therefore cannot be recommended.

Section snippets

Methods

The study population included individuals on PD therapy with anuria receiving care in a Dialysis Clinic Inc unit or the New Haven continuous ambulatory PD unit. Patients included prevalent and incident patients on PD therapy between January 1, 1994, and January 31, 2005. Data for all individuals were obtained from the computerized medical record and provided as a fully de-identified file. Patients and caregivers are instructed to indicate anuria in this record or report anuria at the time of

Patient Population

There were 1,770 PD patients with anuria in the data set. Three hundred thirty-eight individuals were excluded from the analysis (268 without a clearance measure after anuria, 25 developed ESRD before age 18, and 45 with inaccurate data making calculation of dialysis time [vintage] not possible [eg, date of death before date of anuria]). After eliminating these individuals, there were 1,428 PD patients with an available Kt/V value at the onset of anuria and 1,416 with a Ccr value. Individuals

Discussion

In a group of anuric US PD patients, many of whom were overweight, we found that Kt/V less than 1.7 (calculated using actual body weight) was associated with increased risk of mortality and hospitalization, and this result persisted after multivariable adjustment. Kt/V of 1.7 to 2.0 compared with Kt/V greater than 2.0 was not independently associated with adverse outcomes in these anuric patients. These results confirming the KDOQI 2006 minimum Kt/V of 1.7 in anuric patients are important

Acknowledgements

The data were presented, in part, at the North America Chapter Meeting of the International Society for Peritoneal Dialysis, Hollywood, FL, June 1-3, 2007.

Support: None.

Financial Disclosure: Dr Hebah is an employee of Dialysis Clinic Inc.

References (25)

  • KDOQI Clinical Practice Guidelines for Peritoneal Adequacy, Update 2006

    Am J Kidney Dis

    (2006)
  • J.F. Winchester et al.

    The 2006 K/DOQI guidelines for peritoneal dialysis adequacy are not adequate

    Blood Purif

    (2007)
  • Originally published online as doi:10.1053/j.ajkd.2008.05.013 on July 3, 2008.

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