Rigid following of dogma will not be best for all patients

Editor—As general practitioners who run a training scheme we found the series “Getting research findings into practice” thought provoking.¹ The most difficult part of general practice is arriving at a diagnosis, and the articles seem to start after the crucial decisions of general practice have been taken, after the art has been practised.

In 1948 Ryle wrote: “The three main tasks of the clinician are diagnosis, prognosis and treatment. Of these diagnosis is by far the most important, for upon it the success of the other two depend.”² Often the diagnosis of disease is much less objective than we as doctors would like and is not based on one simple test—consider angina, asthma, epilepsy, and depression. Patients often come with a loose amalgam of symptoms to their general practitioner, who tries to make sense of it with a mixture of open and closed questions, postures, pauses, and tests.

We have found it helpful to use a framework to explain why general practitioners’ knowledge of patients is important. We believe that all patients have their own inherent set of predictive values, which may change with time according to their experience. Patients who consult infrequently are more likely to have disease with a given symptom than those who consult frequently in whom numerous investigations over the years have failed to identify clinically significant disease. General practitioners learn to assign increased validity to the concerns of an experienced mother. Doctors may have feared that every minor symptom they developed as students heralded the onset of a rare and life threatening syndrome, yet as qualified doctors they can ignore serious problems in themselves.³

Predictive values of individual patients can help general practitioners determine the best course of action and enhance use of resources. They must not be used to deny patients tests or referrals, but they help in understanding the case and pre-empting results. Indeed, high predictive values are likely to facilitate earlier detection of disease. Patients with thin files merit great caution.

Students and house officers are often taught the blunderbuss approach to diagnosis: ask enough questions and organise enough tests and the “answer” will appear. We try to help doctors become aware of the bigger picture and not to rush in to assign labels of disease at an inappropriately early stage. We recognise that evidence based medicine demands the right questions and correct interpretation of answers but a rigid following of dogma will not be best for all patients.