Re-evaluation of solute transport groups using the peritoneal equilibration test

To determine if the previously described peritoneal equilibration test (PET)-determined solute transport groups, as defined by Twardowski, fit our patient population.

We reviewed the 195 initial standardized PETs (on 195 patients) performed through our peritoneal dialysis program since 1989. Using the method originally defined by Twardowski using the means and standard deviations of the PET-determined dialysis/plasma ratio (D/P) of creatinine and dialysate-to-0 hour dialysate (D/D0) glucose values, transport groupings for our patient population were determined. Comparisons were then made between patient populations.

The mean 4-hour D/P creatinine in our patients was 0.70 +/- 0.10. This compares to a mean of 0.65 +/- 0.15 as determined by Twardowski, and indicates that our patients have higher mean solute transport characteristics and tighter ranges within transport groups than previously reported. Only 2% of our patients fell into the previously described low (L) range, with 30% low average (LA), 51% high average (HA), and 17% high (H). Using our data, we would redefine the groups by a 4-hour D/P creatinine as L < 0.60, LA = 0.60-0.70, HA = 0.70-0.80, and HA > 0.80. Using these values, our population fits a Gaussian distribution with 17% L, 31% LA, 33% HA, and 19% H.

Our patients have higher mean solute transport and tighter ranges within transport groups than previously reported. Using the previously defined PET-determined transport groupings, low transporters are particularly underestimated. If our population data are representative of the peritoneal dialysis population as a whole, these ranges should be redefined.