The value of the GP's clinical judgement in predicting dementia: a multicentre prospective cohort study among patients in general practice.

Background: Clinical judgement is intrinsic to diagnostic strategies in general practice; however, empirical evidence for its validity is sparse.
Aim: To ascertain whether a GP's global clinical judgement of future cognitive status has an added value for predicting a patient's likelihood of experiencing dementia.
Design and Setting: Multicentre prospective cohort study among patients in German general practice that took place from January 2003 to October 2016.
Method: Patients without baseline dementia were assessed with neuropsychological interviews over 12 years; 138 GPs rated the future cognitive decline of their participating patients. Associations of baseline predictors with follow-up incident dementia were analysed with mixed-effects logistic and Cox regression.
Results: A total of 3201 patients were analysed over the study period (mean age = 79.6 years, 65.3% females, 6.7% incident dementia in 3 years, 22.1% incident dementia in 12 years). Descriptive analyses and comparison with other cohorts identified the participants as having frequent and long-lasting doctor-patient relationships and being well known to their GPs. The GP baseline rating of future cognitive decline had significant value for 3-year dementia prediction, independent of cognitive test scores and patient's memory complaints (GP ratings of very mild (odds ratio [OR] 1.97, 95% confidence intervals [95% CI] = 1.28 to 3.04); mild (OR 3.00, 95% CI = 1.90 to 4.76); and moderate/severe decline (OR 5.66, 95% CI = 3.29 to 9.73)). GPs' baseline judgements were significantly associated with patients' 12-year dementia-free survival rates (Mantel-Cox log rank test P <0.001).
Conclusion: In this sample of patients in familiar doctor-patient relationships, the GP's clinical judgement holds additional value for predicting dementia, complementing test performance and patients' self-reports. Existing and emerging primary care-based dementia risk models should consider the GP's judgement as one predictor. Results underline the importance of the GP-patient relationship.
(© British Journal of General Practice 2019.)