english.prescrire.org > Spotlight > Archives : 2011 > Knowing the natural course of a disease makes for better decisions on whether or not to treat

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Knowing the natural course of a disease makes for better decisions on whether or not to treat

Knowing how a disease is likely to develop in the absence of treatment helps to evaluate whether or not a treatment is useful, and whether its harm-benefit balance is favourable.

Are a treatment’s adverse effects acceptable in view of its efficacy, and in view of what will most likely occur in the absence treatment? The answer is not obvious.

Many illnesses are harmless, with a quick return to the former state of health and often with no lasting ill-effects (sore throat, diarrhoea, conjunctivitis, etc.). While short-term treatment sometimes affords relief from the most bothersome symptoms, patients who prefer to do without are taking no particular risks. Drugs whose adverse effects are disproportionate should be avoided.

Some diseases fluctuate, getting better, going into remission, worsening more or less rapidly (cancer, Parkinson’s disease, asthma, etc.), and do not get better on their own. If some treatments may offer a cure, or slow the progression, most often they only partially alleviate some of the symptoms. Choosing not to undertake these treatments does not constitute an undue risk; it avoids the adverse effects, but leaves the symptoms to be endured.

For some recurrent disorders, such as herpes labialis (cold sores), choosing to forego treatment aimed to prevent recurrences (in order to avoid adverse drug effects) does not create undue risk, as long as the recurrences do not create a risk of serious complications.

Sometimes complications can arise. They may be more frequent, or more severe, in certain persons who are especially vulnerable. Their potential seriousness must be taken into account when deciding whether or not to initiate a treatment to prevent these complications. Sometimes in the absence of preventive treatment, it is better to keep an eye out for complications and, possibly, treat them early on.

©Prescrire 1 August 2011

"Évolution naturelle des maladies : que se passe-t-il sans traitement ?" Rev Prescrire 2011; 31 (334): 566-567.
For more information:

Contents of  the special
issue of La Revue Prescrire
"Affections du quotidien -
Retenir les traitements utiles,
sans ou avec médicaments"
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