Optimal dialysis improves uremic pruritus.

The authors analyzed data on 59 hemodialyzed patients who did not have significant disorders of calcium and phosphate metabolism and found that more than 60% suffered from disabling pruritus possibly related to chronic uremia. Both biochemical correlates of the prevalence of pruritus and dialysis efficacy calculated by urea kinetics were investigated. Significantly higher values of blood urea nitrogen and plasma beta 2-microglobulin just before the dialysis session were observed in pruritic patients with lower dialysis efficacy estimated by Kt/V urea and normalized protein catabolic rate (nPCR). After 3 months without changing the dialysis prescriptions, 16 patients with a mean Kt/V urea and a normalized protein catabolic rate (nPCR) of 1.28 and 1.22 g/kg/d, respectively, experienced significant reductions in the degree of pruritus estimated by the pruritic score, from 12.6 +/- 5.1 to 6.3 +/- 3.2. Twenty-two patients with a mean Kt/V urea and an nPCR of 1.09 and 1.01, respectively, continued to have severe pruritus (score: 12.3 +/- 4.7 to 12.7 +/- 6.4). In 9 of 22 patients with prolonged severe pruritus, dialysis efficacy was heightened with an increase in dialyzer membrane area of more than 0.3 m2. Seven of nine patients with increased dialysis prescriptions had significant reductions of the mean pruritic score, from 12.6 +/- 4.8 to 6.3 +/- 2.4, which inversely related to the significant increase of Kt/V urea from 1.05 +/- 0.25 to 1.24 +/- 0.33; among patients whose dialysis prescriptions were not changed, only one had a significant reduction in score. The authors concluded that higher dialysis efficacy with good nutritional state reduces the prevalence and degree of pruritus in hemodialyzed patients.