MPH Master pieces

Teamwork and breast cancer survival

In 1995 Gillis and Hole showed that women with breast cancer survived longer if treated by specialists: a 16% survival advantage compared to women treated by non-specialists. They concluded that

"Survival differences of the magnitude demonstrated have implications for the provision of services for the treatment of women with breast cancer. There is a need to improve equity in the treatment of breast cancer."

A current paper gives the story of  what happened next in Glasgow. Note the careful definition of 'multidisciplinary team' - Definition, definition, definition: without it everything is a fog and you learn nothing!

 

 

Helicopter ambulances

Helicopter ambulances are noisy, shiny and expensive - sexy in fact. So that makes any evaluation hugely emotive and hugely difficult.

Here is a recent study from the USA. The crucial question is whether like has been compared with like. With a seriously injured patient, you are more likely (perhaps) to call for an air ambulance. When hospital is reached, some trauma centres may perform better than others at saving life. The effort is made to sort that out by "propensity matching" and by analysing separately for Level I and Level II trauma centres. Propensity matching is an increasingly used technique which aims to control for severity. The analysis was restricted to severe trauma only. I'm slightly bothered that patients who died before reaching hospital were excluded, because maybe all that flying around may be more likely to cause death in transit - or the reverse: but either way it seems to be that this info should be included.

With such a large study, all differences will be statistically significant - the key question is whether the differences are large enough to be important.

Two final points. Geography matters - the speed of a helicopter is more relevant in the wilds of Nevada than in the suburbs of Surrey. An early evaluation in the UK was pretty downbeat. Part of the reason then was that the speed of the air ambulance was more than offset by huge delays in the hospital. Hopefully now that we are getting trauma care sorted out that is no longer true, but it is only this month that trauma centres have been officially designated (and hence properly staffed and on standby) in the south of England

And when all that is sorted out, there remains the economic question. Helicopters are hugely expensive: would the money have been better spent on putting out more ground ambulances?

Is suicide preventable?

If someone is determined enough to kill themselves, you can't stop them. You could sedate them or restrain them or put them on a 15-minute watch but sooner or later you will have to ease up. And that allows the space for them to commit suicide.

So on one reading, suicide cannot be prevented. This has resulted in much fatalism in mental health services.

But on another reading, it can, at least to some extent. All you need to do is implement a small set of recommendations, as this paper shows. It's an ecological study but well designed and executed, with limitations frankly acknowledged.

One sentence in the report made me angry:

"Services that did not implement recommendations saw little reduction in suicide."

Were these services arrogant (we don't need recommendations)? Or ignorant (unaware of national recommendations)? Or just plain indolent (can't be bothered)?

Just about the only acceptable excuse would be that there were too many other priorities and too many other recommendations. But what, for a mental health service, is more important than prevention of suicide?

See a previous post for someone who did take suicide seriously.

Too old at 50

When you read a study like this you want it to be wrong. That is, if you are over 50 yourself.

The attention grabbing result is that surgeons aged over 50 got worse results than those aged 35 to 50. How can we pick a hole in that? The first temptation is to note that the study was based in France and blame it all on garlic and red wine.

Resisting that temptation, we can move on to methodology. Actually, the paper seems quite strong on that. A research question focussed on a well defined operation, with prospective data collection on surgical complications, and good compliance.

One possible explanation  for older surgeons doing less well might be failure to adopt newer techniques but the authors tell us that thyroid surgery really hasn't changed much over the past few decades.

The relationship between age of surgeon and complication rate is assessed through logistic regression to deal with confounding factors such as case mix. Often papers using these sophisticated techniques give you no sight of the raw data, which makes it very difficult to get a feel for what is going on. This paper does not have that failing - there is a useful set of graphs with the raw data. These allow us to see that the whole 'worse over 50' bit depends on just three or four individuals, and in fact the oldest of them is better than his slightly younger colleagues.

What does it all mean? I'm not sure.  But at a minimum it should prompt further studies which hopefully will be as well executed and reported as this one.

 

 

the inverse care law

The inverse care law, coined by the great Julian Tudor Hart, states that those most in need of care receive it least. Here is a glimpse into one mechanism by which this law operates.

Tudor Hart served a deprived population in south Wales. Here is a paper which sums up his life's work.

Outcome measures

Something a bit different today as there doesn't seem to be much of interest in the journals.

Suppose you were asked to come up with some indicators of how well your local health service was performing. It has already been agreed that the five domains of interest are:

1. Preventing premature death
2. Good quality of life in chronic disease
3. Speedy recovery from acute illness
4. Good experience of care
5. Patient safety

What indicators would you suggest? Here are the ones your colleagues in the Department of Health came up with.

 

ISTCs

The Independent Sector Treatment Centres were politically contentious, and the arguments for and against were conducted in a data-free environment. We like our NHS, so there was plenty of support for claims of botched operations at ISTCs were terrible with the NHS left to pick up the pieces: or alternatively a grudging admission that the outcomes of treatment at ISTCs were ok BUT ONLY because they cherry picked the easy cases. Some people managed to make both claims at the same time.

So here are some data, published two years in arrears. No doubt the arguments will continue, not least because of all the things mentioned in the 'limitation' section of the discussion.

This paper is a good example of pragmatic evaluation, which is what you often have to do with political initiatives. When you can't randomise, you have to make do with matching, and since matching is never perfect / never as good as randomising, you are left to wonder if you really did compare like with like.

The scope of the study was ambitious - data collection on all patients treated for a period of 16 months, and patient reported outcomes (hence requiring return of a questionnaire). 

 

The ecological fallacy

The ecological fallacy is a problem of cross level inference - wrongly transferring conclusions from one level of aggregation to another. Specifically, applying group data to individuals. Here is a contemporary example:

Dropout from substance abuse programmes is associated with worse outcomes, so programmes with high follow-up rates should be better for patients. Right? No, because that's the ecological fallacy at work. This paper shows you the maths of the fallacy. I must admit that even when shown the maths I still can't quite see how it works. I've got a niggling feeling that it may be because facilities with very high rates of follow up are putting all their efforts into that - hitting the target - and not into providing good treatment. 

Makes you think about all those other hospital-level indicators, doesn't it?

Meanwhile over at the IJE, some diligent Dutchmen have shown that Robinson's original work on the fallacy contained an error which lay undetected for 50 years.

 

Safer hospitals

You don't often see evaluations in the UK of organisational change but here is a good example. It is probably relevant that the initiative was funded by a private organisation: they wanted a decent evaluation. The evaluation consisted of a mix of quantitative and qualitative: statistical measures and interviews with staff.

The aim was to improve patient safety in four study hospitals (later disseminated more widely). Great use was made of statistical process control charts.

The number work showed no detectable effect of the intervention, but this as the authors emphasise was against a high baseline and a rising secular (i.e. NHS wide) trend in the control hospitals. The ethnography was interesting - enthusiasm at the top but mystification at the bottom. The authors point out that the hospitals didn't really have an organistional strategy for delivering the change.

Organisational change is really difficult, or as one of my favourite book titles has it 'Hope is not a strategy'.

Data alert! cancer survival

Much is made of the apparently poor survival of cancer patients in England, and this leads to calls for increased funding for cancer, relaxation of judgements about cost-effectiveness and more. But mortality from breast and bowel cancer are declining in the UK so we can't be doing all that badly. A useful commentary in the Lancet points out how misleading some of these comparisons can be.