Insulin Resistance and Hepatitis C Virus-Associated Subclinical Inflammation Are Hidden Causes of Pruritus in Egyptian Hemodialysis Patients: A Multicenter Prospective Observational Study

BACKGROUND: Pruritus is one of the most common and disturbing symptoms in hemodialysis (HD) patients. The pathogenesis of pruritus in HD patients is multifactorial; however, a little progress in understanding this pathogenesis has been achieved. OBJECTIVES: To evaluate the frequency and risk factors of pruritus among HD patients in Dakahlia, Egypt. METHODS: A total of 193 patients from 4 HD centers were included in this study. Pruritus intensity was assessed by visual analog scale. All patients were assessed by clinical and laboratory parameters, such as age, sex, duration of dialysis, dialysis adequacy, urea, calcium, phosphorus, parathyroid hormone, fasting insulin, fasting sugar, HOMA-IR, serum ferritin, high-sensitive C-reactive protein (hs-CRP) and hemoglobin. They were also investigated for hepatitis C virus (HCV) infection by HCV enzyme-linked immunosorbent assay, HCV-PCR for plasma and buffy coat for further detection of occult HCV infection. RESULTS: Male gender, dialysis duration, inadequate dialysis, anemia, high ferritin, hyperphosphatemia, hypocalcemia, hs-CRP, and insulin resistance were characteristic features in pruritic patients (p = 0.01, 0.006, 0.0001, 0.047, 0.01, 0.0001, 0.024, 0.000, and 0.0001, respectively). Significant positive correlations were found between pruritus score and each of age (p = 0.002, r = 0.222), duration of dialysis (p = 0.03, r = 0.151), serum ferritin (p = 0.001, r = 0.213), serum phosphorus (p = 0.0001, r = 0.59), fasting insulin (p = 0.001, r= 0.273), and HOMA-IR (p = 0.0001, r = 0.349), while there was a negative correlation with Kt/V (p= 0.0001, r = -0.459). Linear multivariate regression analysis showed that age, duration of dialysis, serum phosphorus, Kt/v, and hs-CRP were good predictors for pruritic score in HD patients. All HCV-infected patients (who were positive for both plasma and buffy coat HCV-PCR) had pruritus with -significantly higher pruritus score than non-infected patients (p = 0.009), they also showed significantly higher fasting insulin, HOMA-IR, and hs-CRP levels (p = 0.0001). CONCLUSIONS: Uremic pruritus (UP) is a serious problem in HD patients. hs-CRP, male gender, dialysis duration, insulin resistance, dialysis inadequacy, and hyperphosphatemia are positively correlated with the intensity of UP. HCV infection is associated with severe UP, insulin resistance, and inflammation.