Long-term clinical parameters after switching to nocturnal haemodialysis: a Dutch propensity-score-matched cohort study comparing patients on nocturnal haemodialysis with patients on three-times-a-week haemodialysis/haemodiafiltration

Abstract

Objectives: Nocturnal haemodialysis (NHD), characterised by 8-hour sessions ≥3 times a week, is known to improve clinical parameters in the short term compared with conventional-schedule haemodialysis (HD), generally 3×3.5-4 hours a week. We studied long-term effects of NHD and used patients on conventional HD/haemodiafiltration (HDF) as controls.

Design: Four-year prospective follow-up of patients who switched to NHD; we compared patients with patients on HD/HDF using propensity score matching.

Setting: 28 Dutch dialysis centres.

Participants: We included 159 patients starting with NHD any time since 2004, aged 56.7±12.9 years, with median dialysis vintage 2.3 (0.9-5.1) years. We propensity-score matched 100 patients on NHD to 100 on HD/HDF.

Primary and secondary outcome measures: Control of hypertension (predialysis blood pressure, number of antihypertensives), phosphate (phosphate, number of phosphate binders), nutritional status and inflammation (albumin, C reactive protein and postdialysis weight) and anaemia (erythropoiesis-stimulating agent (ESA) resistance).

Results: Switching to NHD was associated with a non-significant reduction of antihypertensives compared with HD/HDF (OR <2 types 2.17, 95% CI 0.86 to 5.50, P=0.11); and a prolonged lower need for phosphate binders (OR <2 types 1.83, 95% CI 1.10 to 3.03, P=0.02). NHD was not associated with significant changes in blood pressure or phosphate. NHD was associated with significantly higher albumin over time compared with HD/HDF (0.70 g/L/year, 95% CI 0.10 to 1.30, P=0.02). ESA resistance decreased significantly in NHD compared with HD/HDF, resulting in a 33% lower ESA dose in the long term.

Conclusions: After switching to NHD, the lower need for antihypertensives, phosphate binders and ESA persists for at least 4 years. These sustained improvements in NHD contrast significantly with the course of these parameters during continued treatment with conventional-schedule HD and HDF. NHD provides an optimal form of dialysis, also suitable for patients expected to have a long waiting time for transplantation or those convicted to indefinite dialysis.

Keywords: albumin; erythropoietin; haemodialysis; nocturnal haemodialysis; phosphate binders; propensity score matching.

Figure 1

Hypertension control in nocturnal haemodialysis versus haemodialysis/haemodiafiltration. Left: systolic (upper two lines) and diastolic (lower two lines) blood pressure (mm Hg) in propensity-score-matched nocturnal haemodialysis (NHD, dark lines) and haemodialysis/haemodiafiltration (HD/HDF, light lines) patients over the course of 48 months. Right: number of different antihypertensive agents in propensity-score-matched NHD (dark line) and HD/HDF (light line) patients over the course of 48 months. OR <2 types NHD compared with baseline P=0.02; OR <2 types NHD vs HD/HDF P=0.11. 95% CIs are shown. Number of NHD/HD/HDF patients available for analysis at 0 months: 100/100; 12 months: 57/74; 24 months: 35/51; 36 months: 20/34; 48 months: 11/22.

Figure 2

Phosphate control in nocturnal haemodialysis (NHD) versus haemodialysis/haemodiafiltration (HD/HDF). Phosphate (lines, mmol/L) and number of different phosphate-binding agents (bars, same axis) in propensity-score-matched NHD (dark lines/bars) and HD/HDF (light lines/bars) patients over the course of 48 months. OR <2 types NHD compared with baseline P=0.01; OR <2 types NHD vs HD/HDF P=0.02. 95% CIs are shown. Number of NHD/HD/HDF patients available for analysis at 0 months: 100/100; 12 months: 57/74; 24 months: 35/51; 36 months: 20/34; 48 months: 11/22.

Figure 3

Albumin in nocturnal haemodialysis (NHD) versus haemodialysis/haemodiafiltration (HD/HDF). Albumin (g/L) in propensity-score-matched NHD (dark line) and HD/HDF (light line) patients over the course of 48 months. NHD compared with baseline P=0.19; NHD vs HD/HDF P=0.02. 95% CIs are shown. Number of NHD/HD/HDF patients available for analysis at 0 months: 100/100; 12 months: 57/74; 24 months: 35/51; 36 months: 20/34; 48 months: 11/22.

Figure 4

Erythropoiesis-stimulating agent (ESA) resistance in nocturnal haemodialysis (NHD) versus haemodialysis/haemodiafiltration (HD/HDF). ESA resistance (DDD/Hb/kg/week) in propensity-score-matched NHD (dark line) and HD/HDF (light line) patients over the course of 48 months. NHD compared with baseline P<0.01; NHD vs HD/HDF P<0.001. 95% CI are shown. Number of NHD/HD/HDF patients available for analysis at 0 months: 100/100; 12 months: 57/74; 24 months: 35/0; 36 months: 20/0; 48 months: 11/0. DDD, defined daily dose; Hb, haemoglobin.