Medicine, evidence & decision-making
The phrase “this medicine works” compresses several different questions: for whom, against what, compared with what, how large the benefit is, and at what cost in adverse effects. A doctor who explains uncertainty is not rejecting science. They are translating group data into a decision for an individual.
1. What the evidence shows
NICE guidance on shared decision-making requires healthcare professionals and patients to discuss reasonable options, their benefits and harms, and what matters to the patient together. Where available, the conversation should use comprehensible absolute figures.[1]
NICE patient decision aids are intended to supplement, not replace, a conversation with a healthcare professional. They help compare options and uncertainty, but they are not a stand-alone recommendation for every person.[2]
A Cochrane review of placebo interventions found no generally significant effects on binary and objective outcomes. Some continuous patient-reported outcomes, particularly pain, showed variable effects that were susceptible to bias.[3]
2. How to read the claim in context
A relative reduction in risk can sound large even when baseline risk is small. The absolute difference therefore matters to a patient: how many people out of a hundred the treatment will help, how many it will not help, and how many will experience a serious adverse effect over the given period.
A group average cannot identify in advance the particular person who will benefit. Biomarkers and clinical experience can refine the estimate, but usually cannot eliminate uncertainty. An honest plan therefore also includes a review date and a rule for when to adjust the treatment.
The placebo effect is not an explanation for every outcome and should not be used to trivialize symptoms. The context of care can affect perceived symptoms, while the medicine’s specific effect and the natural course of the condition need to be assessed separately.
- Treatment effects are probabilistic and depend on the population and outcome.
- Absolute risk is often easier to understand for decisions than a relative percentage alone.
- Shared decision-making includes both evidence and the patient’s values.
- The exact outcome for a particular person before treatment begins.
- The individual balance of benefit and harm without a diagnosis, dose and medical history.
- Whether a study’s general result applies to someone who was not represented in it.
3. Five questions to ask
- What is my baseline risk without treatment?
- How many people out of a hundred will the treatment help, and over what period?
- What are the common and serious harms?
- What other options are available, including watchful waiting?
- When and by what criteria will we decide together that the plan should change?
4. Conclusion
Openly acknowledged uncertainty is not the opposite of expertise. It is a condition for a free and safe decision: the patient knows what to expect, what remains unknown, and when the choice will be revisited together.
— Jiný Kontext