Itchy skin--a clinical problem for haemodialysis patients.

BACKGROUND: Uraemic pruritus affects many patients receiving chronic dialysis therapy for end-stage renal disease. It is a distressing symptom which has a negative impact on quality of life (QoL) of the patients. The condition is also very frustrating for both patients and physicians since no effective treatment for relief of the itch has been demonstrated. The pathophysiological mechanisms of pruritus are mainly unknown despite several hypotheses presented. Recent concepts refer to changes in the opioidergic system and derangements of the immune system.
METHODS: In the Dialysis Outcomes and Practice Pattern Study (DOPPS I, 1996-2001) pruritus was assessed by a self-reported questionnaire. The relationship of pruritus to morbidity, mortality, QoL, sleep quality and patient biochemical laboratory data was studied in >200 randomly selected haemodialysis (HD) facilities in seven countries. Pruritus data were collected from >6000 HD patients. Analyses were adjusted for age, gender, race, Kt/V, haemoglobin, serum albumin, serum calcium, serum phosphorus, 13 comorbidities, depression, years on dialysis, country and facility clustering effects.
RESULTS: Moderate-to-extreme itch was observed in 46% of prevalent HD patients. Differences in pruritus prevalence were found between countries (ranging from 38% in France to 55% in Italy) and facilities (5-75%). Pruritus was more common in patients on HD >3 months than in patients starting HD. A number of patients' serum characteristics, including high calcium, phosphorous and calcium x phosphorous product levels, were significantly associated with pruritus. Patients with moderate-to-severe pruritus were more likely to feel washed out and to have poor sleep quality, physician-diagnosed depression and a reduced QoL than patients with no or mild pruritus. A significant 15% higher mortality risk was observed in pruritic HD patients but this significance was not seen after adjusting the data for sleep quality measures.
CONCLUSIONS: The self-reported prevalence of pruritus in HD patients is relatively high, 40-50%. Pruritus is associated with poor outcomes and a higher mortality risk, probably attributed to poor sleep quality. Better therapeutic treatments are needed for relief of distressing uraemic itching in HD patients.