Interpreting Risks / Benefits of Treatment

Patients have every right to be afraid of the medical system.  The tests we do, and the treatments we give or perform, have inherent dangers, just like everything (such as driving on an interstate, etc.).  But itโ€™s important to view these risks unemotionally and logically.  Just because your uncle or friend had something bad happen, does not mean that this is likely to occur to you (or anyone else).  About 1 in 50,000 people may die from an aspirin, if they happen to have the worst kind of allergy to it.

Virtually all of the medicines we prescribe have a favorable risk-benefit ratio.  In other words, the chance of something bad resulting is much less than the benefit it may confer.  This is of course relative; take, for example, cancer chemotherapy.  Side effects may include vomiting, fevers, hair loss, & on rare occasions even death.  But the benefit may be living longer, or even curing the cancer.

The same is true for any surgery.  Nature never meant for our bodies to be cut open; nonetheless, in a fair many cases, operations may be life-saving (Nature may not have meant for us to live very long either).  Cosmetic surgery, on the other hand, has its risks of disfigurement and even death.  Only a person themselves can decide if a procedure is worth the risk.

Anybody who is about to have any sort of surgery, or undergo any major any new medical treatment, should always ask their provider for the following numbers (or estimates):

  • Whatโ€™s the chance of success?  Of partial success (would be defined in each case)?
  • Whatโ€™s the chance of harm occurring?
    • Specifically, what harm?  Mild nausea?  Death?
  • Whatโ€™s the chance of harm occurring from the disease or condition itself?
    • What would happen without the treatment?

So if a treatment has, say, a 10% chance of success, and a 75% chance of serious side effects, well, maybe donโ€™t opt for it.  But if the disease needing it has a 100% chance of imminent mortality, well, maybe say โ€œyes!โ€  We need to know these numbers before undergoing anything major.

Relative Risks vs. Absolute Risks — This difference is important to understand when you read or hear media reports or advertisements. A drug company, for example, may boast that their new product “decreases death by 50% compared to standard treatment !!!” Sounds good, doesn’t it? But that depends. Let’s say that standard treatment saves lives in 2 out of 1,000 people, while the new drug saves 3 out of 1,000.

The extra “1 life” equals 50% of the original 2 who were saved, so the claim is true — the “50%” is a “relative” improvement. But we really want to know the “absolute” improvement, which here is not so impressive (just an extra 1 in 1,000). For most things, absolute differences are much more important than relative ones, although the latter is what usually gets touted.

Some Stories

A medical assistant had a patient with HIV who sneezed in her eye.  She was very upset, and hoped there was something we could do.  There is in fact medicine she could take which might help prevent infection, but I recommended against it.  Why?  Because the risk of getting HIV from a blood-splash to the eye is less than 1 in 1,000 (& sneezes donโ€™t carry blood).  The patientโ€™s HIV was under excellent control, meaning he wouldnโ€™t even transmit it by unprotected sex. 

I asked her if she wears a helmet while driving, in case of a major accident โ€“ of course not.  Well, that would help save her life more so than trying preventive treatment in this case.  She smiled (gratefully).

Another patient needed medication for latent tuberculosis (TB), to prevent it from becoming active.  At his age, there was a 1-in-500 risk of liver damage, but a 10% lifetime chance of active TB.  He didnโ€™t quite understand my explanation, so I tried, โ€œTake Russian Roulette for example; the odds are one-in-six,โ€ and he replied, โ€œI know, I played that once.โ€ [!!!!!]

Unfortunately, life and society work against us.  On the internet there are countless anecdotes preaching horrible nonsense.  If you read them, look for hard data, or good explanations, instead of arguments or polemics.  The same goes for all the drugs advertised on TV, which my patients sometimes ask for.  Theyโ€™re all profit-makers, and most donโ€™t offer much advantage over the drugs we have.  And we always see happy actors bouncing joyfully in  nature while the sing-song background monotone lists a wide array of dangers (including death).

For pain, over-the-counter medications like acetaminophen (Tylenolยฎ) and topical gels are equally effective as prescription-strength NSAIDs (ibuprofen, etc.), without risk of stomach or kidney damage.  Yet people often want something โ€œstrong,โ€ which truly doesnโ€™t make sense, but convincing is very hard (although there is additional placebo relief from getting prescriptions).

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