Incidence and Risk Factors for Pruritus in Patients with Nondialysis CKD

Background Pruritus is a common symptom experienced by patients with nondialysis CKD, but risk factors for incident pruritus in this patient population have not been evaluated.Methods We identified 1951 participants with CKD in the Chronic Renal Insufficiency Cohort Study without pruritus at the baseline assessment. Pruritus was assessed by the Kidney Disease Quality of Life-36 (KDQOL-36) instrument, and moderate-to-severe pruritus was defined as a response of 3 or higher on a Likert scale of 1-5. We used time-updated multivariable joint models to evaluate the association of patient clinical characteristics, eGFR, and laboratory parameters with incident pruritus.Results Over a median follow-up of 6 years, 660 (34%) participants developed incident moderate-to-severe pruritus, with a higher incidence rate observed among participants with more advanced CKD. In multivariable models, the hazard ratio (95% confidence interval [CI]) for pruritus associated with a 10 ml/min per 1.73 m2 lower eGFR was 1.16 (95% CI, 1.10 to 1.23). Older age ($65 years), higher body mass index, diabetes, current smoking, opioid use, depressive symptoms, and serum parathyroid hormone were also associated with a higher risk of incident pruritus, whereas low serum calcium (< 9 mg/dl) was associated with a lower risk (all P < 0.05). Serum phosphate was not associated with incident pruritus in the primary analysis.Conclusions A substantial proportion of patients with nondialysis CKD develop moderate-to-severe pruritus. Although lower eGFR is associated with the risk of pruritus, other comorbidities, particularly depressive symptoms, were potential risk factors.