We’re talking about acute kidney injury (used to be known as acute renal failure) tonight on Radio 4 at 9pm.

There has been a paper today resulting in headlines like

‘Thousands die of thirst and poor care in NHS’

‘1,000 patients die each month from avoidable kidney problems”

Today programme, at 1.22

Updated; full text of interview follows between John Humphrys and Marion Kerr.

JH. At least a thousand people are dying in hospital every month because something has gone badly wrong with their kidneys and it hasn’t been spotted or at least nothing’s been done about it. It’s known by doctors as ‘acute kidney injury’. I’m joined by Marion Kerr who is the health economist at Inside Health Economist , she’s written about the economic impact of acute kidney injury. Good morning to you – Injury sounds like something horrible has happened to you -punch  in the back or something – we’re not talking about that, we’re talking about people whose kidneys have been damaged, because, mostly because they’ve been dehydrated.”

MK. “That’s exactly right. We’re typically talking about somebody – well let me give you an example. A case that’s known to me. A woman who went into hospital, she had no history of kidney problems, she had a broken leg, she had an operation for her broken leg, was discharged from hospital. And over the subsequent days she became very ill, she had a severe infection, she became very dehydrated, she was vomiting, she had 6 conversations with people at the GP surgery, including the GP, in the course of a week, no one suggested any problem with the kidneys, she was given antibiotics for the infection, and so on, eventually she took herself back to accident and emergency, and was admitted to hospital, at that point she was told, there is a problem with your kidneys, and she was put on an iv drip to rehydrate her. But, there was a technical problem, with the cannula in the drip, over a weekend, so she was left with 48 hours over the weekend without the drip, and her kidneys deteriorated further. And by the time the problem was really grasped, on the Monday, she was down to 10% kidney function, which is a life threatening situation. She was in a sense one of the lucky ones, she did survive it, many people die of acute kidney injury, but she has been left with permanently severely damaged kidneys.

JH. I was going to ask you whether the kidney recovers after something like that.

MK. Some degree of recovery is possible, but clinical studies suggest that even amongst patients who appear to make a complete recovery, they are at an increased risk of kidney problems further in life and many of them over the long term will end up needing dialysis or transplant.

JH Can I ask a really naive question, are both kidneys affected in the same way as it were.

MK Not necessarily, but I think that in a situation where somebody as in the case  that I’ve cited is down to 10% kidney function, then clearly both kidneys will have been impacted.

JH. Right. Now doctors obviously know about the effect of dehydration on kidneys so the obvious question is why isn’t this being spotted?

MK I think that’s a really challenging question.

JH Sounds a very easy one if you see what I mean

MK Yes in a sense because we are talking about basic care here, we are talking about identifying patients who are at risk, we know what the risk factors are, we are talking about monitoring patients so they don’t get seriously dehydrated, we are also talking about catching it early if it happens so that you prevent the problem becoming very very serious. I think one of the reasons that it has been underrecognised by doctors as well as by everybody else, is that in the past there hasn’t been a clear definition of it, in recent years a definition has been put together and that has opened the way for the kind of through study that we’ve done trying for the first time to get the full measure of it. To work out how many people are we talking about here, how many deaths, the numbers are deeply shocking, and also, how much does it cost the NHS each year.

JH. But why should it cost the NHS anything to make sure that everybody on their books whether they’re in hospital or a GP’s patient gets enough moisture, enough liquid, to enable their kidneys to function?

MK The truth is that that costs very little. What costs the money is doing things badly.

JH Exactly.

MK So we have found a lot of the costs that we have counted are because people who develop acute kidney injury stay in hospital very much longer than similar patients who don’t have acute kidney injury, they are very often admitted to critical care, and that’s very expensive.

JH So therefore, isn’t the answer quite simply to say to every doctor and every nurse in the health service make sure the patient is properly hydrated – full stop.

MK I completely agree. And I think, as a health economist, you more often than not work in situations where you are looking at something that has a substantial price tag for the NHS. And you’re  saying the NHS could potentially improve patients’ lives  but it costs a lot. It is something we should prioritise – this is a win/win situation.

JH Exactly. A glass of water costs nothing.

MK Where actually – you can save lives prevent suffering and you can save the NHS money in the process.

My notes

I found this rather astonishing, as the strong implication is that a lack of patients being given fluid is responsible for all the incidences of acute kidney injury.

This isn’t true.

The study itself looked at HES (hospital episode statistics) and hospital records of serum creatinine (a marker of kidney function). It found far more people who had variations in their kidney function before and after hospital stays, and the authors use this to support the view that there are far more kidney injuries than are currently coded.

However, we don’t know whether these variations were because of medications started in hospital (for example, ACE inhibitors can cause a decline in kidney function which is OK, if monitored, because there is still an overall benefit). We also don’t know whether this is more of a pattern of a slow decline of chronic kidney disease that was already in motion before the hospital admission.

This study did not look and see whether poor care or dehydration was a cause of kidney injury, and I think the press release AKI press release 160414

was very unhelpful.

No wonder, since it’s coat-tailing onto the NICE  press release of last year starting

“The National Institute for Health and Care Excellence (NICE) has published a new guideline which promises to save thousands of lives and hundreds of millions of pounds each year. The new guideline will help prevent, detect and treat acute kidney injury (AKI), a condition that affects one in six people who are admitted to hospital and although it is completely preventable, can lead to death in one in four of those.”

It’s not completely preventable, sadly, and not completely preventable with more fluids either.

Read about the prevention, multiple causes, and treatments here.

How many cases of acute renal failure can be prevented?

The most detailed analysis is I think the National Confidential Enquiry, who look with enormous detail at the care of sample of people who died of renal failure. Their aim is to look for deficiencies in care so that this can be remedied.

They found that in 69% of deaths, there was good clinical practice, 18% could be improved, and 4% were inadequate.

They found that 14% of deaths due to acute kidney injury were avoidable.

They did not find that dehydration was the cause in each of these. Instead, a lack of fluid volume is described as a risk factor, along with age, chronic kidney disease, sepsis, weight, and medication.

Clearly, good medical practice is all about trying to improve on what we are doing. It’s right that we should critically evaluate what we are doing and try and get better.

But it’s essential that people get good information about the causes of serious health problems and realistic advice on what we can do about it.

This study did not find that thirst was the cause of death in these patients, unlike the suggestion from the headlines. The evidence does not suggest this is the case from the Confidential Enquiry – though poor care was found to be a factor, and should be addressed, not  dismissed. But if we try and address the wrong problems, we won’t move forward.

Acute kidney injury is complex, multifactorial – and will not be sorted out simply by getting more inpatients to drink more water.