The presence of glomerular filtration in dialysis patients is associated with improved survival and quality of life. This study explores the time course of the glomerular filtration rate (GFR) between 1 year before and 1 year after the start of haemodialysis (HD) and peritoneal dialysis (PD).Methods
This study included 1861 incident dialysis patients (NECOSAD cohort; 62% male, 60 ± 15 years, 61% HD, GFR 5.2 ± 3.6 mL/min/1.73 m2). A decline of the GFR was estimated using linear mixed-effects models adjusted for age, sex, primary kidney disease, cardiovascular disease and diabetes. The rate of decline was allowed to change at a certain point in time.Results
The decline of the GFR attenuated from −0.53 mL/min/1.73 m2/month (95% CI: −0.58, −0.48) in the period before the start of dialysis to −0.12 (95% CI: −0.20, −0.04) at 2–4 months of dialysis in all patients. In HD, decline attenuated from −0.51 (95% CI: −0.57, −0.44) to −0.14 (95% CI: −0.26, −0.02); in PD from −0.55 (95% CI: −0.62, −0.48) to −0.11 (95% CI: −0.23, 0.01). In patients who started dialysis with a GFR equal/above median GFR at dialysis start, the decline attenuated (at 3 months) from −0.70 (95% CI: −0.78; −0.62) to −0.21 (95% CI: −0.36; −0.05). In patients who started dialysis with a GFR below median GFR at dialysis start, the decline attenuated (at 1 month) from −0.73 (95% CI: −0.88; −0.58) to −0.04 (95% CI: −0.27 , 0.19).Conclusions
The apparent decline of the GFR slows down after 2–4 months of dialysis. This decline was similar in HD and PD patients, although at a different level of GFR. Further studies are needed to examine explanations for this phenomenon.