When to start should dialysis
This a controversial area [“not another one. Is it complicated (again) docs?!” CKDEx Ed]
Yup, sure is. And doctors tend to vary with regard to recommending an earlier or later start to dialysis. The ‘earlier start’ group tend to want to avoid the risks of an emergency start (e.g. at 2am co-ordinated by junior hospital doctors).
The ‘later start’ group say ‘dialysis is unpleasant and onerous, and is usually permanent, so only start it when absolutely necessary’.
Either way, most doctors agree dialysis should be started:
1. If you are unwell
With symptoms or complications of advanced CKD including a danger sign:
- Shortness of breath – due to fluid overload causing pulmonary oedema (water in lungs)
2. Blood tests
- High blood potassium – persistently > 6 mmol/L
- If you have reached Stage 5 CKD (i.e. have a GFR of <15 ml/min) – or a creatinine > 500 mcmol/L – whatever the symptoms
Note. This is a general rule only. There are different levels for different people based on age, gender, ethnicity, and muscle mass
3. Other factors
That need to be taken into account are:
- Too much acid in the blood – shown by a blood bicarbonate of < 15 mmol/L
- Unable to control BP – with levels above 180/100
- Other non-specific symptoms – e.g. not eating, sleeping etc.
Note 1. High-risk patients – e.g. with diabetes or heart failure – may be started earlier.
Note 2. Dialysis should always be started before the GFR has fallen to 5 ml/min, even if optimal pre-dialysis care has not been provided and there are no symptoms
Note 3. To ensure that dialysis is started before the GFR is 5 ml/min, doctors should aim to start you by a GFR of >10 ml/min.
These indications are partly based on some European guidelines (Tattersall, 2011).
Is there any evidence that starting dialysis earlier is better?
Not much. One Australian study (IDEAL study, Cooper et al, 2010) looked into the question of when dialysis should ideally start. 828 patients with advanced chronic kidney disease took part in the study.
They were divided into two groups: In one group, dialysis was started earlier – on average at a GFR of 9 ml/min. In the other group, dialysis was started later. There the GFR had already dropped to 7 ml/min on average.
The comparison of the two groups showed no differences between starting dialysis earlier and later. For example, there was no difference in terms of deaths or heart attacks. Infections of the arteriovenous fistula (see below) were also equally common.
“So it is still possible to wait a little and use the time to carefully prepare for the dialysis if there are no symptoms that make it an urgent need.”
What is needed to prepare for dialysis?
For peritoneal dialysis
A peritoneal dialysis (PD) catheter (tube) needs to be inserted into the abdominal at least 6 weeks before dialysis is needed. After a recovery and training period of two to three weeks, peritoneal dialysis can be started.
The catheter should happen at least six weeks before it is needed, to allow for the fact that a second operation may be needed to get the PD catheter going (or sometimes a second catheter).
For haemodialysis
A fistula (arteriovenous fistula, AVF) needs to be created by a surgeon. This is a connection between a vein and an artery in the forearm that is used to access the bloodstream in haemodialysis.
It is best to plan the procedure at last three months before starting dialysis. This is because the fistula needs 6-8 weeks to ‘mature’ (grow) so it is ready to be used – and to allow for a second operation as 75% of first fistulas do not work initially.
Other things you should consider
Your eGFR is not the only thing you and your doctor should look at in deciding when you should start dialysis. You will also consider:
- How bad are the symptoms of kidney failure?
- Your age and presence of diabetes and/or heart failure. Generally if you are older (say, >75 years) or have either of these two conditions, an earlier start is recommended
- Your general health aside from your kidney failure
- How do you feel? Do you have the energy to do your daily activities?
- Your ability to make lifestyle changes and to commit time to dialysis.
Consensus view
Although there are pros and cons of an earlier and later start to dialysis, most doctors tend to favour starting earlier, to avoid the risks of an emergency start.
Summary
We have described when to start dialysis. There are different views. But an earlier start may carry less risks.
Other resource
At what GFR level should dialysis start?
Last Reviewed on 24 June 2024