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Monday, 24 December 2018

Asking the wrong question about bed occupancy doesn't help fix the problem

Campaigning for the NHS to have more beds is a distraction from searching for the most effective way to improve the flow of patients through hospitals. The right question is "which actions could we take now to improve flow". More beds is a bad answer to that question. Worse, the metrics we use actively distract the system from looking for the right answer. The NHS desperately needs to do better.

Bed occupancy in the English NHS has reached new record levels at the end of 2018 and this has, yet again, led to calls for the NHS to increase the number of beds (see this in the BMJ, this from the BMA and this in the Independent). The argument is that England has few beds relative to peer group countries and has been cutting them over the last two decades. So, reversing that trend would ease winter pressures, increase hospital safety and reduce long waits in A&E.

But there is a problem with this interminable debate: the answer campaigners propose assumes the wrong question has been asked. And it naively assumes that the solution would have the intended effect. Worse, it distracts from any proper analysis of the problem and the search for other effective solutions.

It also constantly repeats dubious statistics about what works which also distract from any useful understanding of what the problem is.

The right question to ask is "what intervention would most increase the capacity of hospitals to treat patients quickly and effectively". And "more beds" is far from being a useful answer to that question.

So here are a few thoughts about why we are having the wrong debate and what we can do about it.

You can't add more beds quickly
The simple solution "lets have more beds" sounds easy but isn't. Though not every campaigner stops after demanding more beds, many do. But this is just passing the buck and not actually helping much.

The problem isn't that the NHS doesn't have enough beds. The problem is it doesn't have enough staff to man the beds at currently accepted levels of safe staffing or relax the rules about safe staffing. You can only overcome the staffing problem if you can recruit more staff. But, to paraphrase Dido Harding, the problem is that not enough people want to work for the NHS.

To get more staff you need a source of qualified recruits (Brexit isn't helping with that) and a working environment that doesn't drive them away. And you can't improve the working environment without understanding why it is currently unattractive. Which implies fixing other problems before you can recruit the staff needed to man the extra beds. But every time the call is made for more beds, the system and commentators on it are distracted from the search for those other problems.

Campaigning for more beds is a little like a doctor whose primary advice to patients is to be less sick: it almost sounds plausible but does fuck all to fix the problem.


Adding more beds doesn't necessarily fix the problem
The idea that adding more beds would automatically fix the problem is naive. It hides a deeply false assumption about how admissions and discharges work in a real hospital.

The intuition that for a given sick patient there is a fixed number of days they need to spend in a bed is plain wrong. But the idea that more beds would lead to reduced occupancy implicitly assumes this is true. We know it isn't.

There are several different lines of evidence that point to this intuition being wrong.

The first is empirical evidence about what happens when more beds are added to a system. The Modernisation Agency had interesting evidence about this in the early 2000s. They showed clear evidence that while adding extra beds lowers the bed utilisation in the short term, the benefit disappears quickly because the length of stay rises in the medium term eliminating the benefit.

And it is easy to see why if you know how discharge processes work in the NHS. To get a patient out of a bed you have to coordinate several activities: they have to be assessed as fit to go home; they have to get their take home medicines; they have to have transport; discharge letters have to be written… But these activities are often not coordinated and unnecessary delays are common. Where there are many free beds and few problems admitting new patients there is little incentive to coordinate or speed those processes, so delays increase and patients spend longer in the beds. When there are few free beds, the system feels pressure to discharge more patients and they speed up, lowering the length of stay.

That this is a problem is reinforced by other strands of evidence. Clinical audits of all the patients currently occupying beds often suggest that a quarter to a half of them are fit to leave an acute hospital (but haven't been discharged yet for reasons unrelated to how fit they are). The delayed discharge stats–which assign primary responsibility for the delays to long stay discharges–usually pin more of the blame on hospitals than on social care organisations (despite the social care problems being talked about a lot more).

Adding more beds doesn't change the discharge process but reduces the incentives to get it right. Perhaps putting more effort into consistent disciplined discharges would yield a faster benefit than adding more beds (and also lay the foundation for extra future beds to provide a bigger benefit).

The way we measure bed occupancy is wrong
This brings us to another very serious problem: we measure the wrong thing in current metrics about bed occupancy. Arguably the current metrics for occupancy in the NHS are actively harmful to better bed management.

I've ranted about this problem before. In essence what the normal metric measures is how many beds are occupied at midnight on a single weekday. But this tells us nothing useful about whether beds are being used effectively not least because it tells us nothing about whether beds are available at the time of day when they are actually needed for admissions. On a typical day something like 15-20% of patients will be discharged. But, if those discharges happen late in the day the beds will not be free at the time of day when there is the highest demand for empty beds (which peaks around midday). What matters for the patient and the hospital is whether there is a free bed at the specific hour of the day when the bed is needed. Whether the bed is free at midnight is only vaguely related to whether it is free when it is required. And not being free at the right time leads to very long delays for admission and those delays dramatically increase mortality for patients (according to emerging evidence) never mind the increased clinical workload and stress for staff.

The single thing a hospital can do to get more free beds at the point where they are needed is to change the timing of discharges. Doing this makes no difference to any of the commonly reported metrics about beds (it doesn't affect midnight occupancy nor does it alter length of say). So the metrics everyone looks at completely fail to inform anyone about the most effective action they could take to get more free beds at the point of need and therefore better flow of patients through the hospital. If anything, the current metrics actively distract hospitals from the most effective actions they could take.

Of course most hospitals have some process to get a grip on where there free beds are. But those processes are rarely informed by good data on the live state of the beds. Imagine arriving at a hotel to occupy a room you booked weeks ago only to find the hotel has to send someone to walk the corridors to find out which rooms are free. That's not too far from how many hospitals manage their beds. Automated systems to record the live, hour by hour, bed occupancy are extremely rare despite the fact they would create vital data for doing a better job of managing the beds and support big improvements in discharge planning and patient flow.

We could probably get bigger and faster improvements if the central NHS bodies abandoned the current metric and, instead, insisted that every hospital should have reliable, real time occupancy statistics. At least then there would be evidence to drive better discharge timing and planning which could easily yield far bigger benefits for patients than most other initiatives.

85% occupancy is a stupid target that actively harms hospital strategy
The majority of stories on the latest bed crisis will quote the "safe" occupancy level for hospital beds of 85%. But this number is nonsense and focussing on it distracts from good bed management. It is a classic zombie statistic popular not because it is useful in any way but purely because it fits in a nice headline.

Few people read the original source of the number or understand the assumptions behind it. There are several problems with the number and its implications for what hospital policy should be.

A very detailed explanation for why the specific number is almost always the wrong target is given in this excellent paper by Simon Dodds. Part of his argument is that hospitals need to know for themselves what their target should be based on their characteristics (size, timing and volume of patient flow…). A focus on the 85% actively distracts local management from understanding their local circumstances and adopting the right policy to improve it.

Another reason for discounting the 85% is that the model that generated it deliberately ignored some of the most important factors that hospitals can control. Both admissions and discharge are assumed to be basically random which they are not. More importantly, the model completely ignores the issue of discharge and arrival timing so give a result that is true only if hospitals can do nothing about timing (hospitals could control the timing of elective admissions and the timing of all discharges and emergency admissions are fairly predictable).

We have a widely quoted target that encourages hospitals to ignore both their specific local circumstances and many of the most important actions that could improve their local flow of patients. A target that encourages hospitals to ignore what they do know and distracts them from what they could do about it is not a useful target.

What should hospitals be doing?

The campaign for more beds is bad for the NHS because it implicitly asks the wrong question. We should be asking "what actions can we take now to most improve the flow of patients though hospitals". There are plenty of answers to this question that could yield improvements far faster than any reasonable strategy to add more beds. And, even if we do need more beds, there are plenty of other actions that the NHS needs to undertake first before the extra beds will provide much benefit for patients.

Adding more beds is not a useful short term solution anyway as it is impossible to deliver without other parts of the NHS being improved (staff recruitment and retention for example). Staffing problems are, in turn, driven by the poor working environment in many hospitals. And this is partly a function of the poor coordination and management of staff, beds and patients and exacerbated by naive management bullying of staff to "work harder". Designing better ways to work would yield both a direct benefit in better patient flow and would also improve the working environment for staff making recruitment and retention better.

The fastest way for a hospital to get better flow is for it to achieve better coordination of the arrival and discharge processes (see this blog for some examples). Getting this right can dramatically increase the number of free beds at the times of day where free beds are needed (even though it doesn't affect the current metrics on occupancy or length of stay). Well-coordinated processes are also less stressful to staff and less wasteful of their time (too much of which is currently spent trying to find free beds or pushing for inappropriate discharges). This might also be the key to improving the retention and recruitment required to actually staff more beds in the future.

Achieving better coordination might require hospitals to invest in both technology to track patients and in the management expertise required to develop better processes for coordinated discharges and admissions.

Not only would a policy focus on better coordination be likely to yield actual improvements in flow relatively quickly, but it might be an essential prerequisite for any future drive to increase the number of staffed beds.

Campaigning for more beds isn't just naive, it actively stops us taking the right action to improve how the NHS manages its beds.

1 comment:

  1. Are we managing occupancy down now? I remember when it was introduced as a way of getting our bloated, inefficient NHS of the early 1990s to disgorge the cash!

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