Great site for doctors

For a couple of hundred dollars a year you get Rick and Jerry discussing 40 abstracts each month to do with primary care or emergency medicine, Rick is front line doc and Jerry an academic doc who works in an emergency department as well as being a critical appraiser. As likable as Rick is I get these abstracts to hear Jerry. We need many more docs like Jerry. He does the statistical and methodological stuff. Sounds great but is it?

Here they talk about blood pressure pills

Here they talk about aggressive treatment of CVD in the elderly

Jerry should write a book for us front line docs - please Jerry

If placing these audios from this great site upsets the guys and or gals who own it please let me know and I'll take them down. I have put them here hoping more docs will listen to Rick and Jerry.

What do I want more information on at the moment?

Long acting beta agonists - there is a major push going on with regards these. NMow we are supposed to be using one of them in a similar way to ventolin.

NNT - osteoporosis

What is the NNT to prevent an osteoporotic fracture using Risedronate or Aledronate? Similarly using calcium and vitamin D? Is it necessary to give calcium supplements as well as risedronate or aledronate?

Great website - here - non drug company funded too

another NNT

NNT - how come some are so different

There's another instructive way to consider the numbers. Suppose that 100 people with high cholesterol levels took statins. Of them, 93 wouldn't have had heart attacks anyway. Five people have heart attacks despite taking Pravachol. Only the remaining two out of the original 100 avoided a heart attack by taking the daily pills. In the end, 100 people needed to be treated to avoid two heart attacks during the study period—so, the number of people who must get the treatment for a single person to benefit is 50. This is known as the "number needed to treat - see rest of
article

Example

Sixty-year-old female with hypercholesterolaemia

The readily available New Zealand cardiovascular risk calculator can quantify absolute risk. With a blood pressure of 130/80, total cholesterol of 7.5 mmol/L, and an HDL cholesterol of 1.1 mmol/L, a non-smoking non-diabetic female has a fiveyear cardiovascular event risk of 7%. It is generally agreed that statins will reduce risk by a third. With treatment the five-year risk is thus about 5%.

When discussing the merit of treatment against the effort and potential adverse effects, consider the absolute risk reduction. About seven in 100 people will have an event in five years with no treatment, but if 100 take the statin for five years, five will have an event.

Beta blockers 20 people for five years
Asprin like drugs 50 people for five years
Statins 100 people for five years
take a look

Here's more on statins

Here's a good one with statins relating NNT to cardiovascular risk
same here NZ calculator

BP treatment 50 to 80 need to be treated for five years to prevent one death. And about 20 for five years to prevent one cardiovascular event.

Here's another list of NNTs
And another list of NNTs

Here Bandolier on NNT and here

some more statin ones in primary prevention and .

• the authors affirm that statin therapy could reduce the absolute risk of coronary events during the next 4.3 years by 0.75% in low-risk patients (NNT= 133), by 1.63% (NNT=61) in moderate-risk patients and by 2.51% (NNT=40) in high-risk patients. They also conclude that it could be cost-effective in patients with an absolute risk over 20% of having a coronary event in the following 10 years. It would not be cost-effective in patients with a risk <10%,>
• the study authors concluded that, in patients without CV disease, statin therapy decreases the incidence of major coronary and cerebrovascular events and revascularizations but not coronary heart disease or overall mortality

Reference:

1. Thavendiranathan P et al. Primary prevention of cardiovascular diseases with statin therapy: a meta-analysis of randomized controlled trials. Arch Intern Med. 2006 Nov 27;166(21):2307-13.

Statins - yet again

Abramson, J., et al, Lancet 369:168, January 20, 2007

These authors conclude that present lipid-lowering guidelines are not evidence-based.

Dr Malcom Kendrick essays

numbers needed to treat

Here are some examples of Numbers Needed to Treat, found at the Bandolier web site (http://www.jr2.ox.ac.uk/bandolier/index.html).

Prevention of post-operative vomiting using Droperidol, NNT=4.4. For every four or five surgery patients treated with Droperidol, you will see one less vomiting incident on average.

Prevention of infection from dog bites using antibiotics, NNT=16. For every 16 dog bites treated with antibiotics, you would see one fewer infection on average.

Primary prevention of stroke using a daily low dose of aspirin for one year, NNT=102. For every hundred patient years of treatment with aspirin, you will see one fewer stroke on average.

Here's another example from the British Medical Journal (Freemantle 1999: 318(7200); 1730-1737). Prevention of cardiac death using beta blockers among patients with previous myocardial infarction, NNT=42. For every 42 patients treated for two years with beta blockers, you would see one fewer death. This is superior to treatment with antiplatelet agents (NNT=153), Statins (NNT=94), or Warfarin (NNT=63), but not as effective as thrombolysis and aspirin for 4 weeks (NNT=24).

Hypertension -numbers needed to treat

Treating newly diagnosed asymptomatic hypertension

In women ages 30 to 54 years (79% white), hypertension treatment results in a 41% risk reduction in fatal and nonfatal cerebrovascular events (95% CI 8-63%, 5 year NNT 264), and a 27% risk reduction in fatal and nonfatal cardiovascular events (95% CI 4-44%, 5 year NNT 259).

numbers needed to treat

This from Therapeutic Letters

The following is from PMCA subscription needed.

So here, from varying sources, are some NNT / NNS figures. You may find some of them very surprising. The determination of NNT / NNS is a moving target and is affected by newer clinical studies that refine our knowledge. So most of these numbers should be considered to be “in the ballpark.”

Mammographic Screening
How many women between the ages of 50-59 need to have a mammogram yearly for five years to prevent one death from breast cancer? The number is about 2,500 such women.

Lipid Treatment
71 patients with known cardiovascular risk factors have to be treated with a statin for 3-5 years to prevent one serious adverse cardiovascular event. But no increase in total mortality or total serious events can be expected. (me here does he mean no decrease) To put this into perspective, at $1,000 per year per patient for statins, for 71 patients taking them for an average of four years, the cost to prevent one serious adverse cardiovascular event is 71 patients x $1,000 x 4 years = $284,000

(See http://www.ti.ubc.ca/pages/letter48.htm)

Me again I checked above URL - this is primary prevention for risk factors not for those having CVD

Prevention of Colon Cancer Death with Occult Blood Testing
The number needed to screen for five years to prevent one death from colon cancer is 1,374 patients.

Prevention of Hip Fracture by Treatment of Osteoporosis
In women without risk factors, approximately 2,000 women between the ages of 60-64 need to be screened and subsequently treated for osteoporosis for five years to prevent one hip fracture (1,000 women if there is at least one risk factor).

Detection of Diabetes in Men With and Without Hypertension
The number is 13 in 55-year-old men with hypertension, and 19 in those without hypertension.

Simple Antihypertensive Treatment for Mild Hypertension
700 patients would need to be treated for one year to prevent one stroke, MI or death in that year.

Prophylactic Antibiotics for Dog Bites
Only about one in 16 patients will benefit.

Compression Stockings to Prevent Post-Op DVT
One in nine patients may be expected to benefit.

Antibiotics to Improve Short-Term Outcomes in Otitis Media
Only one in seven patients can expect to benefit from antibiotics (i.e., decreased symptoms at 7-14 days post onset of treatment).

Aspirin in Healthy Physicians to Prevent an MI or CV Death
The number is 500 over one year.

It's been a while

Finished working in kaitaia Northland, NZ. Now in Auckland being a domestic god while my wife works.We are living in a run down motorcamp in Remuera. It sold a year ago for 11 million. It's going to become an old folks village. Campsites all over NZ disappearing as owners get millions for the land - shame!!

Telecom hotspots $9 per hour - bugger. I just got used to endless high speed mega gigbytes for 40 a month. Oh well.

Probably won't be any medical stuff for a while as cooking is now more my focus, as well as fixing dings in fifth-wheel and ute.

Nice example on the radio today of evidence that suits being used.

Government agency is funding a cheaper ventolin alternative. Same stuff they say - bio equalivalence is the same two. Funny thing is it tastes different and a signioficant number of patients reckon its not as good.

The government agency didn't use a DOEM and certainly not a POEM. They used a COEM.



DOEM is disease orientated evidence that matters. POEM is patient orientated evidence that matters. COEM - I made it up C standing for chemical.

Ask your doctor for POEMs - sing me some poems doc!! We need evidence that matters to us. ASK FOR IT. DEMAND IT. And while you are at it asked for absolute number - ask for NNT and NNH - numbers needed to treat and harm.

How to use research to support your treatment decisions

It can be hard to know which medical research to believe. One day you may hear that drinking alcohol is good for your heart. The next day you may hear that alcohol makes it more likely that you'll get breast cancer. And your friend may swear that a treatment you've never heard of saved his mother's life.

This link will take you to an easy to read series of articles and visual presentations that should help you get a handle on what's involved in research and on using the figures doctors may sling around.

Relative risk - absolute risk - etc

What do those numbers means

Would you be willing to take drug X daily for the next 5 years if significant results from randomised placebo controlled trials showed that:

1. patients taking this drug for 5 years have 34% fewer heart attacks than patients taking placebo; or
2. 2.7% of the patients taking this drug for 5 years had a heart attack, comparing to 4.1% taking a placebo, a difference of 1.4%; or
3. if 71 patients took this drug for five years the drug would prevent one from having a heart attack. There is no way of knowing in advance which person that might be.

Did you make the same decision for all three scenarios? If not, you were fooled by the numbers, because the three scenarios represent the same data from the same trial presented to you in three different ways.