The Relationship Between Serum Interleukin-31 Levels and Chronic Kidney Disease-Associated Pruritus in Patients Undergoing Hemodialysis.

BACKGROUND

Chronic kidney disease-associated pruritus (CKD-aP) has been linked to immune dysregulation, including elevated interleukin-31 (IL-31) levels. However, the limited research on serum IL-31 levels in patients with CKD-aP has yielded inconsistent findings due to heterogeneous patient populations and varied assessment methods. This study elucidated the relationship between serum IL-31 levels, CKD-aP, and its severity in patients undergoing routine hemodialysis (HD).

METHODS

This cross-sectional observational study included patients undergoing HD at Dr. Cipto Mangunkusumo Hospital between April and May 2024. Pruritus was assessed using the visual analog scale (VAS) and 5-D itch scale. Serum IL-31 levels were measured using enzyme-linked immunosorbent assay. Bivariate and multivariate analyses were performed.

RESULTS

Among 70 participants (54.3% male; median age, 52.5 years; median HD vintage, 57 months), 35 experienced CKD-aP. The median VAS and 5-D itch scale scores were 5.3 and 13, respectively, indicating moderate itching severity. Patients with CKD-aP had significantly higher serum IL-31 levels than those without CKD-aP (p = 0.05). Receiver operating characteristic analysis showed modest discriminatory ability (area under the curve = 0.64), with a sensitivity of 51.4% and specificity of 74.3% at a cut-off of 173 pg/mL. A significant association was observed between serum IL-31 levels and CKD-aP (p = 0.03). However, no significant correlation was found between IL-31 levels and pruritus severity as measured by the VAS (p = 0.79) or 5-D itch scale (p = 0.44).

CONCLUSION

Serum IL-31 levels were higher in patients with CKD-aP, suggesting its potential association with pruritus. However, its modest diagnostic performance and lack of correlation with itch severity indicate that IL-31 is unlikely to serve as a standalone clinical biomarker and may have a limited role as an adjunctive or exploratory marker.