FROM JAMA NEUROLOGY
A simple, office-based screening tool was at least as effective as biomarker-based assessments in predicting which patients with Parkinson’s disease are likely to develop dementia in an international study.
The eight-item scale “is a short and easily-administered office tool that despite its simplicity can nonetheless accurately screen for dementia risk in Parkinson’s disease,” investigators noted in reporting the results of an international multicenter study in 607 patients with Parkinson’s disease but free of dementia at baseline. The results of the study, testing the predictive validity of the Montreal Parkinson’s Risk of Dementia Scale, were published online in JAMA Neurology.
After a mean follow-up of 4.4 years, 11.5% of the study cohort developed dementia. Those who were stratified by the scale as having a low risk of dementia had an annual risk of 0.6%. Those in the intermediate-risk group had a 5.8% annual risk of developing dementia, and those in the high-risk group had a 14.9% annual risk.
Compared with patients in the low-risk group, those in the high-risk group had a 20-fold higher risk of dementia, and those in the intermediate risk group had a 10-fold higher risk (P less than 0.001).
A positive screen result – a cut-off of four or above – showed a sensitivity of 77.1% and a specificity of 87.2%. The positive predictive value was 43.9% and the negative predictive value was 96.7%, and the overall area under the receiver operating characteristic curve was 0.877.
Benjamin K. Dawson, from the department of neurology and neurosurgery at McGill University, Montreal, and coauthors said a previous study using a combination of lumbar puncture, dopamine transporter scanning with [123I]FP-CIT single photon emission CT (DaTscan), and clinical markers had an area under the curve of 0.80, while clinical-genetic risk score that included an analysis of GBA mutations had reported an AUC of 0.88.
The Montreal Parkinson’s Risk of Dementia Scale includes eight items: age below 70 years, male sex, falls and/or freezing, bilateral disease onset, history suggestive of rapid eye movement sleep behavior disorder, orthostatic hypotension, mild cognitive impairment, and visual hallucinations.
The authors noted that the risk scores were lower when the cohort was limited to patients without mild cognitive impairment. Because sex was also such a strong risk factor for dementia, the authors divided the results according to sex and found that the scale did perform somewhat better in men.
The authors commented that the main advantage of the Montreal Parkinson Risk of Dementia Scale was its practicality in an office-based clinical setting.
“Featuring demographic data as well as motor and nonmotor signs, the items of the scale are already often screened for in a routine office visit of a patient with [Parkinson’s disease], with no need for biological samples, neuroimaging, or genetic testing,” they wrote. “Therefore, compiling results is rapid for the clinician during a single outpatient office visit, and the results are available without delay or requirement for statistical software.”
The study was supported by the Fonds de la Recherche Sante Quebec and the Canadian Institute of Health Research. One author declared travel and speaking fees and consultancies with the pharmaceutical, and he and two other authors declared a range of grants from other funding bodies including Fonds de la Recherche Sante Quebec. No other conflicts of interest were declared.
SOURCE: Dawson B et al. JAMA Neurol. 2018 Mar 26. doi:10.1001/jamaneurol.2018.0254.