DO STATISTICS LIE? NUMBERS, NUMBERS AND DAMN NUMBERS. THE ISSUE OF NOAC

When I last wrote a critique on Dabigatran in mid 2013, I upset some friends in Boeringher I, who have decided " not to friend me". They took offence at my blog. I was saying that I do not think that Dabigatran was advantages, especially as the cost is significantly more when compared to warfarin.Well the issue lies with statistics. A relative risk reduction of 50% sounds very impressive. But when you look at the actual numbers, the absolute risk reduction was only  0.65%. Wow, what a difference?

Dr John Mandtrola  ( Clinical Electrophysiologist - Louisville Kentucky ) looked into this issue. The actual risk of the new novel oral anticoagulants ( NOAC ), in the managment of atrial fibrillation, comparing NOAC and warfarin, with regards to their stroke risk and their cerebral hemorrahge risk.

Lets take a look at the details.

Lets begin with the meta-analysis on bleeding risk of NOAC Vs Warfarin as published in JAMA Neurology by Chatterjee. The NOAC included dabigatran, apixaban, rivaroxaban, and endoxaban. They enrolled about 60,000 patients. 31,830 patients were on NOAC and 25,661 were on warfarin. There were 186 major bleeds with NOAC use and 317 episodes with warfarin used. They called this a 50% reduction in major bleed. But if you look at this anotherway, the bleeding risk with MOAC is 0.58% and with warfarin 1.24%, an 0.65% reduction in major bleeds. Put another way, if you were to treat 60,000 patients, you can assure 99.4% taking NOAC that they will not have a bleed and 98.8% that they may have a bleed.
Well, that is statistics for you.

Well lets take the second issue. Does NOAC prevent more strokes than warfarin? This was published in the Lancet 2013 in a study by Christian Ruff. They recruited about 60,000 patients. 29, 312 were given NOAC and 29, 229 were given warfarin. There were 911 strokes -embolism in the NOAC gp ( 3.1% )  and 1107 in the warfarin gp. ( 3.8% ), an absolute risk reduction of 0.7%. So if you treat 60,000 patients, you can assure those taking MOAC that they have a 96.9% of not getting a stroke - embolism, and those taking warfarin that they have a 96.2% chance of not getting a stroke or major embolism.

Put this way, things are not so rosy for NOAC not to forget that warfarin is dirt cheap, and NOAC is gold expensive.

I rest my case. I hope that my friends in Boeringher, Bayer, Dachi Sankyo, and pfizer will understand. My is just to tell it like it is.

These are hard times. I need to help the country save as much as much money as I can.