Objectives The objective is to allow evidence obtained from the patient in the form of symptoms, signs and test results to be applied after careful reflection in order to avoid over-diagnosis and over-treatment. EBM focuses on research evidence from assessing the efficacy of treatment mainly using RCTs and tests using sensitivity and specificity. However during a consultation it is also important to explain a diagnosis and decision to patients and colleagues using the evidence obtained from that particular patient. If this is put in writing, it will help the patient (and anyone else seeing the patient) to understand and remember each diagnosis and decision without having to search through the entire medical record. In the context of this conference, it will make the writer pause to reflect and think again as to whether the evidence provided by patient and science justifies each diagnosis and the treatment, thus minimizing over-diagnosis and over-treatment.

Method The first step is to outline the current problems as perceived by the patient. Next, list the diagnoses, tests to be done, the treatments to be stopped, continued and started. Next check that there is a diagnosis that explains each of these actions. All the diagnoses are numbered and the number of the diagnostic indication then placed in brackets after each action. Finally, the outline evidence is placed in brackets after each diagnosis. This includes the presenting finding, the latest marker of progress and the types of finding used to confirm the diagnosis (e.g. ‘clin’ for clinical, ‘haem’ for haematological, etc), with dates allowing a reader to look up the results if necessary. This can be supported by copying text from guidelines. This approach can be used for hospital referral letters and discharge summaries and updated subsequently in primary care and on readmission to hospital.

Results In a study on the accuracy of diagnoses in patients with acute abdominal pain, experienced surgeons made 300 subjective diagnoses of which 235 (78.4%) were correct. If they only committed themselves when they were also able to specify in a thoughtful and logical way with ‘patient’s evidence’ based on symptoms and signs of demonstrable diagnostic accuracy, they made 221 diagnoses of which 200 (95.5%) were correct. However, when they could not support their diagnoses with such evidence in 79 cases, only 35 (44%) were correct. When these evidence-based summaries were drafted on admission to hospital, 60% of patients were discharged within 2 days compared to 40% if this was not done. When such summaries were created with the aid of standard text from guidelines, 80% were posted within a week of discharge compared to 5% of summaries dictated and typed in a conventional manner by a secretary.

Conclusions This is an example of ‘patient’s evidence’ based medicine where each diagnosis and treatment is supported by an outline of that patient’s findings in writing. The patient’s evidence should be supported by research evidence of its diagnostic accuracy during the differential diagnostic process. This can result in reducing the number of diagnosis made and increasing their accuracy, thus reducing over-diagnosis. These summaries support the process by making the writer pause to reflect and think again as to whether the evidence provided by the patient and by science justifies each diagnosis and the treatment, thus minimising over-diagnosis and over-treatment. When copies are given to patients, they summarise the conclusion of shared decision making. They can also improve the efficiency of health care by reducing hospital stays and improving communication between secondary and primary care. The standard text guidelines for diagnostic evidence can also be used in research studies.