Diagnosing dementia with confidence by GPs.

Background: Earlier reports suggest limited clinical reasoning and substantial uncertainty of GPs in assessing patients suspected of dementia.

Objective: To explore the predictors of GPs to decide on the presence and absence of dementia as well as the predictors of diagnostic confidence of GPs.

Design: An observational study was set up among 107 patients of 64 GPs. The GPs were instructed to use the Dutch national dementia guideline on consecutive patients newly suspected of dementia and to register their assessment on a detailed form. The predictors of the presence and absence of dementia according to the GPs and their diagnostic confidence were explored by logistic regression analyses.

Dependent Variables: (i) presence and absence of dementia according to GPs and (ii) diagnostic confidence.

Independent Variables: clinical (cognitive, behavioural, somatic, functional), applications of recommendations, patient related and GP related.

Results: Dementia was diagnosed in 67% of the suspected patients. The presence of dementia according to the GPs was positively associated with observed impairment of the higher cognitive functions, absence of depression and female gender of patients. The GPs expressed diagnostic confidence in 58% of the cases. This was positively associated with application of recommendations, ADL dependency, longer duration, informant availability, restless behaviour and a patient's female gender. Use of the Mini Mental Status Examination was not associated with confidence.

Conclusions: GPs seem to base the diagnosis of dementia on rational grounds. Application of the dementia guideline's recommendations may contribute to more diagnostic confidence.