Overdiagnosis and Chronic Kidney Disease

Last week's Inside Health on BBC Radio 4 was the first of two editions discussing over diagnosis. The suggestion is that we are creating diseases which are, at best, risk factors. Chronic Kidney Disease (CKD), which has been part of the QOF for a few years now, was given as an example.

It is well worth downloading and listening to. Particular focus was placed on the MDRD formula for calculating the estimated glomerular filtration rate. This is the basis for entry to the register.

The formula (taken from Wikipedia) is

There are only two variables for any given person (race and gender are pretty constant). I see a lot of low eGFRs in older patients and wondered how the formula works. I downloaded Gnuplot and, after a bit of reading the manual, plugged the formula in. I have plotted for non black men but the chart would simply be moved a bit to the left or right in other patients.

For those that don't see that many of these things this is a not untypical range for creatinine. 125 is about the top of the normal range in my lab. You can see how the threshold for CKD (and eGFR of 60 or below) drops from a creatinine of 125ish in a 30 year old to 100ish at 90.

This is actually a smaller effect than I thought it would be but it does give some idea of the shape of the formula. What a low eGFR actually means for individuals remains under some debate.

Smoking indicators

The business rules for the QOF are rather murky place and I am grateful to a couple of people who have pointed out some odd things happening in the smoking cessation areas

Just as a reminder smoking cessation advice now applies to all patients in the practice who are over 15 years old and smoke. There is a difference between those with chronic disease and those without that those with chronic disease should have the advice annually (well, within 15 months of the end of the QOF year) and those without within two years (27 months). So for this year the smoking cessation advice requirements applied since January 2011, or 14 months before the business rules actually came out.

Despite fairly minimal change to the wording the actual smoking cessation indicator has changed. Two codes are now needed to pass this indicator. One code from each of the two following groups. The fist group is basically the same codes as before. The patient should receive advice or be referred or pointed to self referral to a smoking cessation clinic.

8CAL	Smoking Cessation Advice
8HTK	Referral to stop smoking clinic
8HkQ	Referral to NHS stop smoking service
8H7i	Referral to smoking cessation advisor
8IAj	Smoking cessation advice declined
8IEK	A declined code
9N2K	Seen by smoking cessation advisor
13p50	Practice based smoking cessation programme start date
9Ndf	Consent given for follow up by smoking cessation team
9Ndg	Declined consent for follow up by smoking cessation team

This is all pretty sensible. Most of the evidence points to a good smoking cessation clinic improving quit rates. However there is now a second part that requires a prescription to be issued. Note in both these areas there is a declined code. I use EMIS PCS at work and the declined codes are not yet available on the system. That is 17 months after they could first require to be entered.

745H	Smoking cessation therapy (and all its subtypes)
8B3f	Nicotine replacement therapy provided free
8B2b	Nicotine replacement therapy
8B3Y	Over the counter nicotine replacement therapy
8IEM	A declined code
Rx	Smoking cessation product prescription

Quite how this helps anything is beyond me. We have a local smoking cessation clinic that does not (or nor does it need to) inform me every time they advice someone to get some patches at the chemist. Logically the most sensible thing for me to do would be to throw patches at patients like confetti. This is likely expensive for my PCT/CCG and, in the curse of QOF, it seems that nicotine therapy may actually reduce quit rates.

Even the evidence quoted in the official guidelines is confused and muddled.

It would be nice if these retrospective changes were corrected in the next ruleset although past experience suggests that this is policy and not error and change is unlikely.

QOF indicators for 2013-14

NICE is currently consulting on the potential new QOF indicators for 2013-14. These are the indicators that could be put forward to the negotiators in the summer for consideration of the following year's contract. There is certainly no guarantee that they would go forward. This year rather fewer than half of the suggestions in the menu actually made it into practice.

As this is a consultation then the more responses the better. My response to the QOF consultation is on the web in the interests of openness. In generally the aims seem laudable although there are some significant practical problems that may arise with the implementation of these indicators. Some clearly need more work but your view may differ and I would encourage you to put them forwards.

Access Databases to download

The access databases are now available on the download page. These are actually version two. If you have downloaded before Saturday night (21st January) there were some errors in the indicator descriptions and some practice codes - basically a lack of 'N's due to over vigorous removal of null values.

You can download this years data or the data for all QOF years. The latter is a very large download and it makes Access run like an asthmatic sloth but that could all be the way I have set it up. I am no Access guru.

You may also have noticed the new timelines on the site. You can see how achievement for an indicator has changed over time. This is something that would not have been possible on the old site - the new database structure makes it much easier.

2011 Data online - and the new site

I am delighted to be able to say that the 2011 data is on the site, and the new version of the site is on line. This currently mirrors of the function of the old site with more detail at the SHA, country and UK level.

There is more functionality to come which is made easier by an entirely new data model in the background. The database will be able to cope with things such as comparisons between years.

There is also a new look which is hopefully easier to find your way around. Search is on pretty much every page. Please do let me know how you find it. Everything can change and this is rather more simple in the new site. I have used Django to build the site which has a very simple template system. I would update the look to this blog but Blogger templates are such horrible things that I really can't figure out at all.

The downloads should be available soon. I need to tidy the database a little first.

Update - and coming soon!

I have not written here for quite a while, at least partly due to there being little going on until the past couple of weeks. I have been writing for the GP Business magazine though in that time.

The data for all four countries has now been released and I am getting it onto the database currently. I am also giving the site a makeover from top to bottom which will increase what is possible and make the whole thing more maintainable. It will also have a new look, have less clutter and have graphs that work where there is no flash (ipods,pads and phones mainly)

This is a pretty big change so I will have to take the site down for 24 hours or so in the next week before it reappears with all the data. New features can be added after that.

Hope to see you there soon!

Blood pressure monitoring

Lots of stuff on the news today about the NICE guidance that all new patients should have an ambulatory blood pressure measurement. Savings of about ten million pounds in five years are promised. But what is the cost?

We can use the QOF data to work this out. As the PP1 indicator applies to all newly diagnosed hypertensives then the denominator is a good indicator of how many have been diagnosed in the previous year. (Acutally it underestimates buy up to 8% but I will let that pass for just now.) The total of the PP1 denominator over the UK in 2009/10 is 278,012

We can buy an ambulatory blood pressure machine. If we pick a decent supplier - I promise I am not on commission here - the cheapest today is £1350 including VAT.

As they go on one day and come off the next these could be used four times a week in most practices - 208 times a year.

Lets do a little bit of maths - 278012 patients per year divided by 208 slots (lets assume perfect useage) needs 1337 machines. At total cost of £1,804,404.

Of course if use is less than perfect - and to operate at all there will have to be some free slots - then the cost will be more. Possibly two to three times as much. This is a big upfront capital cost. Recurring costs will need to be added on as well as replacement costs. I would imagine a machine is going to start to look pretty shabby after 208 uses!