Evaluating the association between alterations in mineral metabolism and pruritus in hemodialysis patients * Avaliação da associação entre as alterações no metabolismo mineral e o prurido nos paciente em hemodiálise

BACKGROUND: Uremic pruritus is the most frequent symptom in long-term hemodialysis patients. Abnormal laboratory parameters have been found with conflicting data. OBJECTIVE: To correlate the prevalence of pruritus with alterations in mineral metabolism in hemodialysis patients. METHODS: This was a case-control study. A hundred and five patients on maintenance hemodialysis were evaluated: a group of patients with pruritus and a control group. They answered a research protocol questionnaire; laboratory data were collected from medical records and the patients with pruritus filled out a visual analogue scale (VAS) to measure pruritus level. RESULTS: The mean age was 51.9 years; 59% of the patients were men and 43% of the patients had pruritus. Xeroderma occurred in 45% of the patients. High levels of calcium were demonstrated in 55% of the patients and 47% had pruritus. 60% of the patients had high phosphorus levels and 43% had pruritus. The Ca/P ratio was normal for all the patients. Parathyroid hormone was high in 95% of the patients, all of them referring pruritus. CONCLUSION: There was a statistically significant association between the group of patients with pruritus and xeroderma. Serum calcium and phosphorus levels, Ca/P ratio, PTHi and size of the dialyzer did not show a statistically significant association with pruritus. Therefore, we found an important relationship between xeroderma and pruritus, with no relation with the assessed laboratory parameters.