Residual Renal Function in Hemodialysis and Inflammation

Residual renal function (RRF) has an important effect on uremic toxin clearance, on volume control, on quality of life, and on mortality. In patients with chronic kidney disease (CKD), microinflammation with an increased percentage of CD14⁺ /CD16⁺⁺ inflammatory monocytes has been reported, even with no clinical evidence of inflammation. No correlation has been established between these and RRF in hemodialysis (HD) patients. Our objective was to assess the relationship between RRF and the inflammatory parameters in HD patients. Cross-sectional observational study was carried out on 69 adult patients on chronic HD for at least 6 months, from which demographic, analytic and HD-technique data were collected and the following were measured: (i) RRF with average urea and creatinine clearance ((CCr + CU)/2) in 24-h urine (if >1 mL/min and diuresis >100 mL/day, RRF was considered); (ii) Inflammation through biochemical parameters (C-reactive protein, β₂ microglobulin, albumin) and monocyte subpopulations in peripheral blood. The average age was 70.9 [40-88] years old; 38 (55.1%) were male; and 25 (36.2%) were diabetic. 43.5% (30/69) presented RRF, with an average of ((CCr + CU)/2): 1.8 (2.6) mL/min and diuresis: 454.5 (569) mL /24 h. Patients with RRF presented lower concentrations of C-reactive protein (6.2 vs 21.4 mg/L) (P = 0.038) and a lower percentage of non-classical CD14⁺ /CD16⁺⁺ monocytes (14.6 vs. 28.3%, P = 0.02). In our study, patients with RRF present lower concentrations of inflammatory parameters, which is another reason why its preservation is an essential objective in HD.