Is concordance the primrose path to health?

The concept of concordance—consensual prescribing—emerged after an inquiry “into the causes and consequences of non-compliance with medicines.”¹ The notion of “doctor's orders,” where the passive patient is given treatment by the authoritarian and supposedly knowledgeable doctor is replaced by the idea of discussion and agreement between patient and prescriber before treatment. The final aim is “to optimise the potential benefits of medical care.”¹ Two thirds of older patients prescribed a statin for coronary artery disease will have given up treatment within two years.² Concordance implies that these patients are denied real benefits if they do not take treatment as prescribed, and informed discussion should improve matters. Constructive dialogue between patient and prescriber is ethically and professionally desirable, even if the public good sometimes demands an authoritarian approach, as with directly observed treatment for tuberculosis or methadone maintenance. Usually, however, the patient, who has most to gain by success and the most to lose from harm, should decide whether to have treatment, and the prescriber should provide information on the risks and benefits to help make the decision.

To make rational therapeutic decisions, we should weigh risk of harm against chance of benefit. Risk is notoriously difficult to calculate, and even where it can be measured accurately, the same absolute risk will be perceived very differently by different people and in different contexts.³ This explains in part why it is hard to establish what risks patients would be prepared to take for a given benefit—for example, a cure for rheumatoid arthritis.⁴ It is also hard to establish how people perceive the chances of benefit. They spend £4.5bn ($7.5bn; €6.4bn) per year on United Kingdom lottery tickets, even though the probability of winning the jackpot is one in 14 million. This does not prove that treatments offering higher chances of benefit are good. A meta-analysis shows that treatment of 1000 people with hypertension (mean blood pressure 177/90) aged between 60 and 80 reduces the number who die in five years from 129 to 111, that is, by 0.36% per year; and all cardiovascular events are reduced by about 1% per year.⁵ The authors concluded that treating healthy elders with hypertension is highly efficacious, but 95% of patients who dutifully take their tablets for five years will be no better off, and there are benefits, too, in neither taking tablets nor regarding oneself as suffering from a medical condition.

It may be possible to discuss the potential benefit and harm from a treatment, and agree with the individual patient what course to take. This will probably be insufficient to influence behaviour. Up to 80% of information given to patients during medical consultations is forgotten at once, and almost half of what remains is incorrect.⁶ “Decision aids,” such as leaflets explaining the options for treatment of specific conditions, improve patients' knowledge and increase their satisfaction with treatment, but rarely, if ever, improve measures of physical outcome.⁷ Many patient information leaflets are unintelligible, anyway.⁸

Patients can intend to take treatment, but nevertheless find it hard to keep to the prescribed regimen. The consequences may be less severe for some drugs than for others but generally act to reduce the benefits that might be expected from clinical trials.⁹,¹⁰ Patient diaries and tablet counts overestimate the degree of adherence to the prescribed schedule when they are compared with more sophisticated methods of assessment.¹¹,¹² We should hardly be surprised that our patients wish to hide their failings from us, and concordance, where the patient and prescriber have discussed in detail the value of adherence, and by implication the price of failure to adhere, may encourage this all too human deceit.

The practical difficulties of providing information, allowing the individual patient to make rational decisions, and translating decisions into action, stand beside the realisation that, in altering behaviour, logic counts for little. Doctors are certainly bad at altering their own behaviour in response to logic. They accept that hand washing can reduce the spread of healthcare associated infection, but they still do not wash their hands.¹³ Such failings do not encourage optimism about concordance.

There is another way in which behaviour may inhibit rational drug treatment. “The strategy of desire,”¹⁴ which appeals to the emotions rather than the intellect, is the foundation of modern ideas of selling. In the United States and New Zealand it has been deployed in advertising of prescription only medicines directly to consumers (that is, directly to patients). The consequence has been an explosive rise in the sales of advertised brands.¹⁵ This reminds us that pharmaceutical companies, enthusiastic partners in the ideas of concordance, want first and foremost to sell medicines. Concordance might increase the sales of medicines, but we should not assume that it will increase the benefits that patients derive from them.