Number needed to...

Number needed to...

One of the conceptually difficult areas of medicine is that while we treat the individual, sometines the benefits are in populations. A statin may only benefit a fraction of those who take the medication. This is expressed as the number needed to treat: how many people need to take a medication to have a favorable outcome in one person. For statins

“In low risk patients the number needed to treat in order to prevent one death per year was 1000.”

That is the nice thing about infectious diseases. Most of the time the number needed to treat is one. Kind of spoils you.

I recently came across another concept: the Number needed to harm, (NNTH) which, if I had ever heard of the concept before, didn’t stick. It is a

measure that indicates how many patients need to be exposed to a risk-factor over a specific period to cause harm in one patient that would not otherwise have been harmed.

Part of this calculus, of course, is the risk of the therapy and the benefit of the therapy vrs the severity of disease. You will offer and accept more risk from a therapy if the outcome is severe, like death.

As best I can tell, most pseudo-medicines have no efficacy with the exception of manual therapy for low back pain. Most pseudo-medicines only have complications to offer patients. So there is no number needed to treat, only number needed to harm.

I cannot find any calculations for NNTH for chiropractic, homeopathy, or acupuncture, the big three of pseudo-medicine. It would be valuable information, although, as in the case of chiropractic, any potential for an adverse effect is denied.  Cannot calculate a NNTH if the intervention causes no complications.

Number needed to harm. It is all that pseud-medicine has to offer.

A whiff of corruption
Herbals for the Heart