Approaches to diagnosing dementia syndrome in general practice

: Determining the value of clinical judgement and tests

Abstract

People with cognitive symptoms often report a long wait to see a specialist in order to be given a diagnosis of dementia or some other disorder, or be told they are normal. This thesis investigates the accuracy of a range of tests potentially suitable for GP use, including GP clinical judgement, for the diagnosis of two target conditions, dementia and normal.
A systematic review was done in five electronic databases. A diagnostic test accuracy study was done in 21 GP surgeries in South West England with a total eligible population of 34,956. Qualitative interviews were done to explore the acceptability of GP diagnosis. From 12,681 citations, 16 were included, referring to 10 studies, of which seven were included in a meta-analysis. For dementia, in the studies at lowest risk of bias, the sensitivity of GPs clinical judgement ranged from 34% (95% CI 18% to 54%) to 91% (95% CI 85% to 96%) and the specificity ranged from 58% (95% CI 51% to 66%) to 99% (95% CI 97% to 100%). In 240 people aged 70 years or more without a previous diagnosis of dementia who had presented to their GP with cognitive symptoms, for dementia using ICD-10 criteria as judged by an expert the sensitivity of single tests ranged from 23% (95% CI 16% to 31%) for TAC to 100% (95% CI 97% to 100%) for MOCA; and specificity ranged from 4% (95% CI 1% to 11%) for Sniffin Sticks to 97% (95% CI 92% to 99%) for FAQ. GP judgement had sensitivity 56% (95% CI 47% to 65%) specificity 89% (95% CI 81% to 94%).
In 26 interviews, GP diagnosis of dementia was judged acceptable if the service was adequately resourced and met the specific needs of patients.
A number of candidate index tests were identified that could be further investigated to help select people with a high probability of dementia in general practice who may not need specialist evaluation for diagnosis.

Date of Award	29 Sept 2020
Original language	English
Awarding Institution	University of Bristol
Sponsors	Wellcome Trust
Supervisor	Yoav Ben-Shlomo (Supervisor) & Sarah Purdy (Supervisor)