The Association of Uremic Pruritus with Blood Lead Level in Prevalent Hemodialysis Patients through Systemic Inflammation

Abstract

he present study is a cross sectional study that investigates the relation between blood lead levels and pruritus in patients with end stage renal disease receiving hemodialysis. 50 patients were enrolled in this study, all were on regular hemodialysis 3 times a week. Patients with primary skin diseases (psoriasis, erythroderma, etc…), HCV positive patients, patients with chronic liver disease and patients with malignancies were excluded. Patients with PTH levels over 300 pg/ml and those with corrected calcium and phosphorus levels over 10.2 and 5.5 mg/dl were excluded from the study. We divided the patients into 2 groups, group 1 (n =10) with no pruritus and group 2 (n=40) with varying degrees of pruritus. In this study we found that: There was a significant difference in blood lead levels and serum ferritin levels between group 1 and 2. Thus serum ferritin and blood lead level were two independent factors that we found to be associated with uremic pruritus. Blood lead related systemic inflammation therefore appears to play an important role in the elevation of serum ferritin in our studied hemodialysis patients.

As well there was a significant difference in kt/v (a measure of dialysis adequacy) between group 1 and group 2 patients ,it was established that patients with uremic pruritus had lower Kt/V values than those without, this in addition to the association of higher levels of urea with pruritus. Group 2 was further divided according to intensity of Pruritus by visual analogue scale ( which consisted of a 10cm horizontal line with 0 point (no pruritus) to 10 points (maximum intensity of pruritus) into mild (n=10), moderate (n=20) and severe pruritus (n=10) . There was a statistically significant difference in serum lead levels in different groups of intensity of pruritus, having higher serum lead levels in patients who exhibited severe pruritus. And there was a significant correlation between blood lead level and blood urea and duration of dialysis. By using multi regression analysis we found that both blood lead level and duration of dialysis together are the most sensitive predictors for pruritus.