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-excellent ideas, James and others -we are acceptin a right diagnosis but this remember me Hoffman JR and Cooper RJ' paper: *For most conditions, the benefit of a given treatment is relative, reducing bad outcomes in a percentage of patients who have the condition. Treatments also produce harm, usually in a fixed percentage of those treated, independent of whether they have the di*sease for which th*e treatment was intended. For example, consider a new **antibiotic, “gorillacillin.” Although gorillacillin is so toxic **that it kills 10% of those who receive it, it is tremen**dously beneficial among patients with the dreaded “in**fectiosis,” decreasing mortality from 50% to 25%. Goril**lacillin is less attractive, however, when only 20% of **treated patients actually have infectiosis; the 10 lives saved **among the 20 patients who would have died are com**pletely offset by the 10 drug-related deaths among 100 **patients treated.* https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/1203523 -un saludo juan gérvas @JuanGrvas 2018-06-14 18:20 GMT+02:00 McCormack, James <[log in to unmask]>: > Hi Rohini - Great discussion - I would like to add my 2 cents worth. > > 1) It is important to think about NNTs for prevention (BP/statins for > heart attacks and strokes) different than for the treatment of symptoms. > The big difference is for heart attacks and strokes neither you nor your > patient will ever know or be able to figure out if they benefit. It is > just a chance thing. > > 2) for symptoms - in your question - you might be able to figure out if > there is a benefit. > > 3) NNTs for symptomatic conditions are not all that useful - although this > condition is trickier because if I am correct one uses the treatment for a > while to reduce infantile spasms and then taper the treatments after 3 > months (for the vigabatrin) > > 4) the problem with NNTs for benefits is that it gives you no idea about > what goes on in the placebo group - what you really need to know is what > happens in the treatment group AND the placebo group > > 5) If I read the paper correctly - and I have no experience with treating > infantile spasms so I might make some incorrect assumptions but this is the > general approach to using NNTs for symptoms - 72% got the desired outcome > (cessation of spasms) when vigabatrin was added to hormones and 57% got the > desired outcome from placebo added to hormones - so for convenience let’s > round the numbers to 75% and 60% respectively > > 6) So if you use the combination, 75% of children will be spasm free > between day 14 and 42 in the combination group. However, 60% in the hormone > only group were also spasm free so if a child is spasm free from the > combination > 80% (60/75) of the time it had nothing to do with the vigabatrin. > > 7) In other words if the combination worked it’s likely not because of the > combination. > > 8) It looks like the only important difference in adverse reactions was in > drowsiness (maybe movement disorder as well). Again it is useful to look at > the differences ~25% in the vigabatrin group and close to 0% in the hormone > group - in other words 1 in 4 will get drowsy and because this almost was > never reported in the hormone alone group, if drowsiness is an issue then > it very likely is because of the vigabatrin. > > 9) Because the combination is more effective (assuming a 15% absolute > benefit is clinically relevant) in my mind it would make sense to start > with hormone plus a very low dose of vigabatrin (decreases the risk of > sedation) and titrate up over a few days - if the spasms go away, I would > stop the vigabatrin because it is likely not because of the vigabatrin and > then if after stopping the vigabatrin they come back, restart vigabatrin at > a low dose > > 10) now all of the above is caveated by the fact that I know nothing about > infantile spasms but I’m speaking more in general about how to deal with > NNTs and symptoms - in fact this condition is different than someone who > has ongoing symptoms. > > See our recent editorial in the BMJ for the same sort of discussion on > depression https://www.bmj.com/content/360/bmj.k1073 > > James McCormack, BSc(Pharm), Pharm D > Professor > Faculty of Pharmaceutical Sciences > UBC, Vancouver, Canada > Co-host - Best Science (BS) Medicine Podcast > > therapeuticseducation.org > > > > On Jun 14, 2018, at 3:48 AM, Rohini R Rattihalli < > [log in to unmask]> wrote: > > I am doing this for the first time, so apologies if I haven't done this > right! > I would be grateful for your advice on the following paper: > https://www.thelancet.com/journals/laneur/article/ > PIIS1474-4422(16)30294-0/fulltext > > I was keen to know that if I chose to change practice based on this > paper, how many children would I treat with both steroids and vigabatrin, > who would have got better with just steroids. > > I did NNT calculation on the internet which said 6.7 patients would have > to receive both treatments (instead of just steroid treatment) for one > additional patient to remain spasm free between 14 and 42 days. Which would > imply to me that I would be subjecting nearly 6 patients to side effects of > vigabatrin when they did not need it. > > Does that sound correct? > > Thanks for your help. > > ######################################################################## > > To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following > link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1= > EVIDENCE-BASED-HEALTH&A=1 > > > > ------------------------------ > > To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following > link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1= > EVIDENCE-BASED-HEALTH&A=1 > ######################################################################## To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1