Medical evidence is in a state of constant flux. Most of us would feel comfortable if amassing research evidence was like completing a jigsaw puzzle. Each new piece would add to the greater picture. Unfortunately, that is not the case. When viewing medical research we must learn, as we did as adolescents, that not everything in our lives fits together in one nice picture. It is much more important to understand how and when to effectively embrace new paradigms and then when to let them go. And not just one concept at a time.
Understanding, tolerating, and nurturing variety and difference is an asset in this world. It is the same for medicine and medical research. What might be good for one individual patient may not benefit another nor the whole community. So, when public health pundits and our clinical colleagues both appear in our electronic mailboxes with different messages, we need to let them both in.
What has been guidance from one group of experts for decades may change seemingly overnight as new evidence arises. Take the recent data about daily aspirin in the prevention of heart disease and stroke. Research published this week sheds a new light. If you don’t have established severe heart disease, then you shouldn’t take aspirin as a preventive measure. Contrary to previous evidence and guideline advice, aspirin does not prevent heart attacks or strokes.
Of course, the evidence about the benefits and risks of aspirin is as old, voluminous, and changeable as assertions about coffee.
As far back as the Assyrians and ancient Egyptians, there is evidence of the use of salicylate-containing plants such as myrtle and willow leaves to alleviate joint pains. Salicylates, or the acid version, salicylic acid, is the main ingredient in aspirin. Pharmaceutical preparations of aspirin came onto the market in the 19th century.
Even after two centuries of evaluation, the use of these preparations remains in a state of flux and seemingly contradictory. Take the use of aspirin in pregnancy. Hippocrates, a well-known medical sage, recommended chewing willow leaves for pain relief in childbirth.
Modern sages have recommended the use of aspirin in pregnancy too. In the early stage, that is before the 16th week of a pregnancy, aspirin can reduce the risk of serious high blood pressure (preeclampsia) but not the preeclampsia associated with the late-stage pregnancy.
Similarly, as recently as five years ago, it was postulated that treatment with aspirin helps maintain cognitive function in older people. Now that evidence has come into question and there is additional evidence about the harms of aspirin in older persons.
If the evidence about pharmacological preparations of aspirin is confusing, think twice next time you add spices to your cooking – unless you’re looking for pain relief. Dried basil, cumin, oregano and cloves all contain large amounts of salicylates.