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.