Rationale for Guideline Kt/V urea Targets for Peritoneal Dialysis
Peritoneal Dialysis Adequacy Targets
Contribution from European Best Practice Guidelines Committee (EBPG).
Source: The current 2005 edition of the guidelines state:
The minimum peritoneal target for Kt/Vurea in anuric patients is a weekly value of 1.7 (Evidence level A); the minimum peritoneal target for net ultrafiltration in anuric patients is 1.0 l/day. (Evidence level B)
The presence of residual renal function can compensate when these peritoneal targets are not achieved.
When the targets are not achieved, patients should be monitored carefully for signs of overhydration, uraemic complaints and malnutrition. Appropriate therapy changes might be considered. (Evidence level C). Some APD patients who use frequent short exchanges and have a slow transport status can fulfill the above targets, but may have a low peritoneal creatinine clearance. In these patients, an additional target of 45 l/week/1.73m2 for peritoneal creatinine clearance should be aimed at in addition to achieving the Kt/Vurea target of 1.7.
Rationale: Two large randomized controlled trials on the effects of peritoneal clearances on survival were considered [1,2]. Both failed to show any benefit from increasing the Kt/V above 1.7/week. However, patients with a Kt/Vurea <1.7/week had more clinical problems, and a small percentage of them needed treatment with erythropoietin [2]. A Kt/V of 1.7/week should be easily achievable in most patients.
Currently, there is insufficient evidence to mandate a minimum Kt/V. Decisions on therapy changes should take the clinical status of the patient into account.
Various retrospective studies showed that daily ultrafiltration rates less than 750-1000 ml were associated with worse survival. The committee wished to draw attention to problems associated with fluid retention, in the absence of data from prospective studies.
For reasons of simplicity and because haemodialysis adequacy is quantified by Kt/V, the committee recommend using Kt/V rather than weekly creatinine clearance. The exception is in patients on APD with low peritoneal solute permeability. In these patients, creatinine clearance will be more representative of the clearance uraemic toxins.
References:
- Paniagua R, Amato D, Vonesh E et al. Effects of increased peritoneal clearances on mortality rates in peritoneal dialysis: ADEMEX, a prospective, randomized, controlled trial. J Am Soc Nephrol 2002; 13: 1307–1320
- Lo W-K, Ho Y-W, Li C-S et al. Effect of Kt/V on survival and clinical outcome in CAPD patients in a randomized prospective study. Kidney Int 2003; 64: 649–656
Prepared on behalf of the Renal European Practice Guidelines Committee by James Tattersall.
