Advantages and limitations of Long Nocturnal Hemodialysis (LNHD)

Abstract

Intermittent long nocturnal hemodialysis (LNHD) combines dialysis and sleep. Its clinical advantages are a reduced ultrafiltration rate, better control of blood volume with improved tolerance of the sessions and cardiac performance, better clearance of phosphates and middle molecules, and better survival in cohort studies. Quality of life is not impaired by the length of the sessions and, when not optimal, improves when transferring from standard hemodialysis (HD) to LNHD. The quality of sleep is sometimes disturbed, but it is not an important cause of exit from the program. The sustainability of an LNHD program depends on the joint medical and managerial will, the selection of stable patients, respect for schedules, and the duration of sessions, which is essential for sleep dialysis. The health authorities must play a role in allowing this modality under acceptable financial conditions. Informing the patient of the existence of LNHD before the dialysis stage is essential, helped by the testimony of peers. Learned societies should support research and the provision of information to nephrologists. Finally, architectural conditions that promote privacy and sleep are key to the success of the program.

INTRODUCTION

Long nocturnal hemodialysis (LNHD) is a dialysis modality that has been prescribed since the 1960s. The length of the sessions at that time (between 8 and 12 hours, 2 to 3 times a week) favored its emergence to allow the combination of dialysis and sleep in young patients returning to work. In the last decade, there has been some confusion in the definition of LNHD. Indeed, the daily practice of chronic hemodialysis (HD) has been highlighted by Frequent Hemodialysis Network (FHN) studies. One of them failed to show a beneficial effect of daily home HDLN on the primary endpoint (combined endpoint of death/ventricular mass or death/physical activity score), mainly caused by the lack of recruitment and inclusion of incident patients[1]. LNHD 3 times a week, which has been practiced for decades, has not been the subject of randomized controlled trials. However, solid observational studies have shed light on their value[2]. Some programs have been developed over the past few years and have been acclaimed by patients and their feedback[3], but others have been discontinued, showing both undeniable clinical interest and operational difficulties. This contribution will highlight the interests and limitations of LNHD at 3 sessions per week (intermittent LNHD).

ADVANTAGES OF INTERMITTENT LONG NIGHT HEMODIALYSIS

Intermittent LNHD was favored by patients during the Etats généraux du Rein in 2013. The Centre de Rein Artificiel de Tassin (CRAT) (Tassin Artificial Kidney Center) has offered this modality since its creation in 1969. A survey with a control group of 59 patients (37 responses) treated with intermittent LNHD is summarized inTable I. Around 73% of the patients had chosen CRAT because of this modality, while 65% of them had already experienced standard HD. No patient wanted to return to daytime dialysis, and 75% liked the length of the sessions, 25% asked for one hour less, and none were willing to dialyze with a standard 4 hours[4]. Clinically, no randomized controlled trial has been conducted on this dialysis modality, and it has been “forgotten” in FHN trials. However, solid data has demonstrated the expected benefits.

Table I.Investigation of intermittent HDLN at the Tassin Artificial Kidney Center[4]

Background and satisfaction with intermittent LNHD*		Reasons for choosing intermittent HDLN
Choice of CRAT** for LNHD	73%	Professional activity	21%
Standard HD experience	65%	Social and family life	73%
Satisfaction with the length of the sessions	75%	Quality of treatment	70%
Wish for one hour less	25%	Sleep/dialysis combination	73%
Wish to return to standard HD	0%
Overall satisfaction with LNHD	89%
Desire for daytime dialysis	2%

1- Ultrafiltration rate and clinical tolerance of the session

In a cohort study, Lacson et al.[5]compared 746 patients who switched from standard HD to LNHD in a dialysis center and 2,062 patients who remained on standard HD. The hourly ultrafiltration rate (UF) decreased from 11 to 6 ml/h/kg in the LNHD group, remaining constant at 12 ml/h/kg in the standard HD group. This result is all the more interesting given that the speed of UF is currently recognized as a risk factor for mortality[6]and that the patients who had switched to LNHD showed a significant increase in interdialytic weight gain of 0.5 kg on average. Interdialytic weight gain is associated with the risk of arterial hypotension during the session[7]. The study of Lacson et al. does not mention this complication in their standard LNHD–HD comparative study. However, Ok et al.[8]reported that 247 patients switched from standard HD to LNHD in a dialysis unit compared to 247 patients who remained in standard HD, matched on 45 criteria and followed for 1 year. The incidence of in-session hypotension requiring saline infusion was comparable at the baseline—60.4 and 67.0 episodes per 1,000 sessions, respectively, decreasing in the LNHD group to 21.2 episodes (p < 0.0001) and increasing to 80.3 episodes/1,000 sessions in the standard HD group (p = 0.15).

2 - Phosphatemia

While phosphatemia quickly reaches a plateau during the session, phosphate clearance is prolonged throughout the dialysis session, as shown by Gutzwiller et al.[9]with 5-hour sessions. In the “case control” study by Ok et al.[8], the mean phosphatemia over 1 year was significantly lower in the LNHD group (3.87 ± 1.20 mg/dl) than in the standard HD group (4.96 ± 1.14 mg/dl), whereas it was comparable at the beginning of the study (4.63 ± 1.32 and 4.82 ± 1.26). The prescription of phosphate binders, stable over 1 year in conventional HD (82.9% of patients treated at the end of 1 year), fell from 83.0% to 22.4% among patients in LNHD. These results confirmed the cohort study by Lacson et al.[10], which found a significant decrease in blood phosphorus levels in LNHD (5.73 to 5.02 mg/dl (p < 0.001)), whereas it increased in standard HD (5.75 to 5.85 mg/dl (p = 0.01)).

3 - Cardio-vascular parameters

In the Turkish case control study[8], 91 and 85 patients, respectively, were analyzed by echocardiography at the beginning and end of the study. Cardiac parameters (atrial volume, ejection fraction, ventricular end-diastolic diameter, and ventricular mass index) were identical at the baseline between the two groups and did not change in standard HD. In LNHD, atrial and ventricular end-diastolic volume and ventricular mass index decreased, and ejection fraction increased significantly. After 1 year, atrial and ventricular end-diastolic volume and ventricular

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