Looking to the future: should 'prognosis' be heard as often as 'diagnosis' in medical education?

Much medical education is concerned with principles of disease diagnosis and treatment. Much medical research is, as a result, concerned to inform those principles with new understanding about the causes and mechanisms of disease and how best to reach a diagnosis and prescribe effective treatments linked to the diagnosis.[1] Primary care education seeks to develop expertise in understanding the patient as a person at the centre of this clinical activity, and in the decision-making, communication and care that must frame a diagnosis and effective treatment for an individual patient. Skills in history taking and examination, knowledge of differential diagnosis, and the use of investigations are taught as means to overcome diagnostic uncertainty and guide decisions about care for patients such as the person with new onset headache who may have a subarachnoid haemorrhage. Primary care education also aims to help the clinician learn how to handle uncertainty when further pursuit of a disease diagnosis is unlikely to influence the choice of treatment or alter the patient’s outcome. Concluding that a patient has simple or mechanical low back pain may not supply a distinct and definite pathological diagnostic label, as compared with, say, diagnosing lung cancer or polymyalgia rheumatica, but it does indicate a low probability of avoidable serious outcomes and provides an alternative to ‘disease diagnostic’ labels. [2] By contrast, a male aged 63 years with new onset loose stools and rectal bleeding may benefit from the search for a diagnosis because it leads to treatment which improves his likelihood of surviving with good health in the future. Diagnosis is of questionable relevance when it arbitrarily labels the patient as having a disease, and is not intimately linked with prognosis – such as a diagnosis of mild hypertension in low cardiovascular risk individuals [3] – or if it causes harm because it leads to excessive or inappropriate treatments and unnecessary investigations, such as a diagnosis of bone fragility in a patient with low hip fracture risk,[4] the phenomenon of overdiagnosis.[5] A broader framework beyond disease diagnosis for teaching and thinking about such decision-making is provided by the science and art of prognosis,[6] which asks whether a decision will affect an individual patient’s future outcome. Disease diagnosis is important when it resolves uncertainty and improves the patient’s prognosis, most obviously in acute illnesses such as the significant unexplained breathlessness in a 40-year-old patient which could signify pulmonary embolism. For many patients, however, diagnosis alone does not provide sufficient knowledge and evidence about likely future health and quality-of-life status to guide care.[7] The diagnosis of coronary heart disease, for example, has been subsumed by different classifications defined by ECG patterns and blood markers, which carry very different prognoses and implications for treatment.[8] A patient in her 80s with a range of chronic medical conditions may have a likelihood of future dependency, hospitalisation and death most strongly predicted by inadequate diet, excessive medication and poor status of her feet, all of which can be altered to improve her prognosis.[9] The increasing volume of information and research about a person’s risk of future health states, from starting points such as blood pressure or blood sugar or genetic markers, or psychological and social factors, adds fuel to the idea that prognosis should take a prominent place beside diagnosis as the basis for decision-making in clinical practice, drawing on the patient’s own wishes and values for the future, in order to deliver personalised useful interventions targeted to improve the patient’s likelihood of achieving those desired future outcomes.[8]