Abstract
Background and Aims
Most patients with end stage renal disease (ESRD) initiate maintenance dialysis in three times per week regime irrespectively of residual kidney function (RKF). Incremental haemodialysis (IHD) showed benefits of starting and maintaining patients on less than three times per week regime, most importantly preserving urine volume output (UVO) and RKF. The aim of this study was to assess the main differences between a group of patients initiating dialysis once-weekly (1xHD) and twice-weekly (2xHD), to evaluate time to dialysis regime change, UVO and patients volume status at the end of study period.
Method
Patients with ESRD who started haemodialysis through the planned IHD (once-weekly and twice-weekly) and were undergoing IHD for at least 4 months (M) were enrolled (n=44) in the study. Study was conducted from January 2016 to December 2019 at dialysis department of our hospital. Patients were divided into two groups: 1xHD (20 pts) and 2xHD (24 pts). They were excluded from the study at the end of study period or earlier if they transitioned to thrice-weekly haemodialysis or died. Patients fluid status and body composition was assessed using results derived from bioimpedance measurements performed using Body Composition Monitor device.
Results
The 1xHD pts were younger (66,8±11,6 versus 67,4±10 years: P>0.05) and weighed less (74,4±14,7 versus 75,5±11,9 kg, p>0,05) with lower BMI. In both groups there were more males (60% versus 62,5%: P>0,05). The most common cause of ESRD in both groups was nephrosclerosis (45% in 1xHD versus 47,1% in 2xHD, p>0,05), followed by diabetic nephropathy (30% versus 20,8%, p>0,05), obstructive nephropathy (10% versus 8,3%, p>0,05), multiple myeloma (10% versus 8,3%, p>0,05), glomerulonephritis (5% versus 8,3%, p>0,05) and others in 2xHD group (12,5%; polycystic kidney disease and chronic interstitial nephritis).
The estimated glomerular filtration rate of all patients at the time of HD initiation was 7,5±2,2 ml/min/1.73m2 (8,2±2,8 in 1xHD group versus 6,9±1,48 ml/ min/1.73m2 in 2xHD group, p>0,05). Baseline daily urine output was similar, 1826,6±344,6 ml/day in 1xHD and 1772,2±343,8 ml/day in 2xHD group (p>0,05).
Patients in 1xHD concluded the study after mean period of 13,4 M (min 4 M, max 35 M). At the end of study period only three patients (15%) continued receiving dialysis once-weekly (mean 14,5 M, min 7 M, max 19 M), 12 pts (60%) transitioned to twice-weekly dialysis regime after 2 to 6 M (mean 3,1 M) and continued to receive this dialysis regime until the end of study period. Four pts (20%) transitioned to full-dose dialysis (mean 18,2 M, 11-24 M).
Most of the patients in 2xHD group (17; 70,8%) concluded study in the same dialysis regime (mean 20,4 M, 4-24 M), 7 pts (29%) transitioned to full-dose dialysis (mean 12,6 M, 5-21 M) and one patient transitioned to once-weekly HD (8M).
At the end of study daily urine output was 1463,1±317,5 in 1xHD versus 1321,1±309,1 ml/day in 2xHD group (p>0,05). Results of assessment of fluid status and body composition at the end of study are in Table 1. We evaluated nutritional status at the end of study: total protein 57,4±8,9 g/l in 1xHD versus 62,8±5,3 g/l in 2xHD, albumin 36,9±10,6 versus 37,6±4,4 g/l, total cholesterol 4,1±1,6 versus 4,4±1,3 mmol/l, triglycerides 1,3±0,8 versus 1,7±0,7 mmol/l (p>0,05 for all parameters).
At the end of the study 70% of patients treated with IHD maintained renal function that was sufficient to continue IHD regime with overall survival rate 90% in 1xHD group and 87,5% in 2xHD group.
Conclusion
IHD, in carefully selected patients with good compliance, provides preservation of UVO and RKF, thus delaying transition to full-dose dialysis and avoiding complications of dialysis, such as intradialytic hypotension and vascular access failure. This type of dialysis is individualized treatment that obtains easier adaptation to dialysis and better quality of life.
The urea transporter UT-A1 plays a predominant role in a urea-dependent urine-concentrating mechanism