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The way that dialysis is normally scheduled in hospitals leaves a gap that may be harmful to the health of kidney patients. If, in addition, patients miss a scheduled session, the risks of hospital admission or death increase dramatically.

When someone’s kidneys are not working properly, waste products and fluid can build up to dangerous levels in the blood. People with kidney failure may need dialysis, which means diverting their blood to a machine to be cleaned. The procedure takes about four hours and is repeated three times a week.

People receiving dialysis have a regular schedule of appointments. They typically receive dialysis either on Mondays/Wednesdays/Fridays, or on Tuesdays/Thursdays/Saturdays. Even if they attend all their sessions, they have a two-day period without dialysis. New research found an increase in hospital admissions and deaths associated with this break in treatment.

If patients miss a scheduled session, the serious health risks increase dramatically. The research found that it is most harmful if patients skip the first or last session of the weekly cycle. When that happens, they effectively go four days without dialysis.

What’s the issue?

Kidney specialists have long been concerned about the possible implications of the weekly two-day break from dialysis. But there has been little reliable evidence to test their concerns.

In addition, if a patient scheduled to receive dialysis on Monday/Wednesday/Friday misses the Wednesday session, they go three days without dialysis. Missing the Monday session means four days without dialysis.

The researchers examined the risks of hospitalisation and death associated with the regular two-day break from dialysis. They also looked at whether missing the first or last appointment of the week (four days without dialysis) was worse for kidney patients’ health than missing a midweek appointment (three days without dialysis).

What’s new?

This cohort study analysed data from 3.8 million sessions of dialysis. It included 9397 patients in 15 European countries who were treated from 2007 to 2014.

One in a hundred sessions – or fewer – were missed from Monday-Thursday. Non-attendance was higher on Fridays (1.4%) and Saturdays (1.2%).

Patients who missed the first or last session of the week (four days without dialysis) had twice the risk of being admitted to hospital or dying, compared to patients who missed a midweek session (three days without dialysis).

The researchers presented their results as if considering a group of 100 patients over one year. This allows them to compare different scenarios. They found that:

  • in the group as a whole, there would be 11 deaths and 66 hospitalisations
  • but among patients who attended three scheduled sessions and then missed one, there would be 52 deaths and 210 hospitalisations
  • the risks were lower among those who attended four consecutive sessions with just a one-day break, with five deaths and 60 hospitalisations
  • even when patients attended all sessions, after the normal two-day weekend break there would be eight deaths and 100 hospitalisations.

Why is this important?

The study provides important data that will inform the debate about the best way to schedule dialysis in hospitals. It confirms the significant health risks associated with the regular two-day break when patients who attend all their appointments still go two days without dialysis.

The results showed  that more patients miss dialysis sessions towards the end of the week when sessions are close to or fall on the weekend. And it highlights the danger to patients of skipping the first scheduled session of the week (four days without dialysis).

Some of these conclusions were previously known, others were assumed. But the scale of the harms demonstrated by the study suggests that medics, patients and hospital officials will want to engage with the issue. For patients, the results demonstrate the importance of attending all their scheduled sessions. Medics and policy-makers may want to look at scheduling. Most policies on dialysis schedules, for example, assume that patients will attend all of their sessions.

What’s next?

The findings emphasise the need for research into different ways of delivering dialysis in hospitals, to address the two-day break problem. The same researchers are using existing patient data to test the benefits of offering four sessions a week. They are also working with other groups in NIHR-funded trials to look at extending the duration of existing sessions overnight in the NightLife Trial.

The stark negative impacts of missing a dialysis session suggest that healthcare professionals need to make the dangers clear to patients if they are choosing not to attend all sessions.

You may be interested to read

The full study: Fotheringham J, and others. Hospitalization and mortality following non-attendance for haemodialysis according to dialysis day of the week: a European cohort study. BMC Nephrology. 2020:21;218.

Fluid overload in dialysis patients may be behind the harms after a dialysis break: Fotheringham J and others. The mortality and hospitalization rates associated with the long interdialytic gap in thrice-weekly haemodialysis patients. Kidney International. 2015;88:569-575.

Extending treatment times may be helpful: Fotheringham J and others. The association between longer haemodialysis treatment times and hospitalization and mortality after the two-day break in individuals receiving three times a week haemodialysis. Nephrology Dialysis Transplantation 2019;34:1577-1584.


Funding: This research was supported by a NIHR Clinician Scientist Award.

Conflicts of Interest: The study author has received speakers fees from Fresenius Medical Care.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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Study author

Kidney patients are some of the most monitored people on the planet. But unfortunately three weekly sessions do not go evenly into seven days. For many years, specialists have believed the two-day break was a problem for patients. This work confirms that the problem is very real and should inform discussions about how to address it.I was surprised at just how much greater the risk of death and hospitalisation was in those who miss an appointment. Previous studies have under-estimated this risk, because they usually start following patients some time after the appointment has been missed. As clinicians, we recognise that patients are balancing their dialysis treatment with the rest of what is going on in their lives. But clinical teams might need to vary their approach to a patient missing a dialysis appointment depending on what day of the week it is.James Fotheringham, Consultant Nephrologist, Sheffield Kidney Institute

Member of the public

The researchers are cautious about saying that non-attendance in itself increases the risk of hospitalisation and death. Even so, the impact of this paper may be to make home dialysis more widely available, although it is not suitable or possible for everyone. Hospital dialysis takes up so much of a person's week that it leaves very little time for ‘real life’. Who could deny patients the weekend break or reinforce the rules rigidly? But patients themselves should understand the trade-offs and the risks they are taking. Newly-referred dialysis patients should be given this information in writing and verbally.Amanda Roberts, Nottingham 
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