Dementia: predictors of diagnostic accuracy and the contribution of diagnostic recommendations

To explore and quantify the relative contribution of guideline recommendations and other determinants in the family physicianamprsquos diagnostic work-up of patients suspected of dementia.

We prospectively studied 64 family physicians in an Eastern district in the Netherlands who diagnosed dementia according to the national Dutch guidelines in primary care. Their diagnoses were compared with the reference standard embodied by the memory clinic team of the University Medical Center Nijmegen.

The physicians evaluated 107 patients older than 55 years suspected of having dementia.

Predictive values of various clinical and demographic parameters were measured in both univariate and multivariate logistic regression analyses.

Activities of daily living (ADL) dependency (odds ratio [OR] = 5.3, P =.03), years since symptoms first started (OR = 1.84, P =.03), and the presence of somatic comorbidity (OR = 0.48, P =.02) independently contributed to the prediction of the presence or absence of dementia. The area under the receiver-operating characteristic (ROC) curve for these 3 variables together was 0.79. The ROC area of the family physiciansamprsquo diagnosis to determine the final diagnosis was 0.74. The number of recommendations applied did not additionally contribute to the assessment of the final diagnosis.

The diagnostic accuracy of the family physician was reasonable. For family physicians, ADL dependency is a better predictor of dementia than cognitive impairment. Family physicians should be aware of diagnostic difficulties in patients with somatic comorbidity. We were unable to confirm the diagnostic value of many of the recommendations of dementia guidelines.