Why we can’t trust clinical guidelines

On 13 April 1990, in an unprecedented action, the US National Institutes of Health faxed a letter to every physician in the US on how to correctly prescribe a breakthrough treatment for acute spinal cord injury. Many neurosurgeons were sceptical of the evidence that lay behind the new recommendation to give high dose steroids, yet when two respected organisations released a review and a guideline recommending the treatment, they felt obliged to give it. Now, over two decades later, new guidelines warn against the serious harms of high dose steroids. This case and others like it point to the ethical difficulties that doctors face when biased guidelines are promoted and raise the question: why do processes intended to prevent or reduce bias fail?

Doctors who are sceptical about the scientific basis of clinical guidelines have two choices: they can follow guidelines even though they suspect doing so will cause harm, or they can ignore them and do what they believe is right for their patients, thereby risking professional censure and possibly jeopardising their careers.1 2 3 4 This is no mere theoretical dilemma; there is evidence that even when doctors believe a guideline is likely to be harmful and compromised by bias, a substantial number follow it.5