The collateral history: an overlooked core clinical skill

Patients with cognitive impairment are often unable to provide information relating to their pre-morbid cognition and function. Such information is essential to correctly identifying delirium and dementia, as well as making an accurate diagnosis and planning appropriate treatment. It is the standard of care recommended by the EuGMS.

We reviewed medical notes and administered a short questionnaire to nursing staff of a convenience sample of 100 patients aged ≥ 75 years admitted to medical wards in a tertiary teaching hospital.

There were 100 patients with a mean age of 82.3 years, 49% of whom were female. Of 43 patients with cognitive impairment, 19 (44%) had a collateral history. Half of the patients described as having dementia did not have any further detail on the severity of dementia documented. Among those for whom a collateral history was obtained, the level of detail regarding pre-morbid cognition, function, mobility, and continence was sparse. Of the total sample, 13% had formal cognitive testing.

Acute illness characteristically causes significant impairments in cognition and function in frail older patients. Identifying and reversing these impairments is impossible without a comprehensive collateral history. It is alarming that such an essential component of clinical assessment is so often disregarded and highlights the lack of awareness from clinicians of the importance of collateral history in the management of patients with dementia and delirium. This must be emphasised in both undergraduate and postgraduate teaching.