JAMA Neurology august 2015
Importance There is increasing evidence that Parkinson disease
(PD) is heterogeneous in its clinical presentation and prognosis. Defining
subtypes of PD is needed to better understand underlying mechanisms, predict
disease course, and eventually design more efficient personalized management
strategies.
Objectives To identify clinical subtypes of PD, compare the
prognosis and progression rate between PD phenotypes, and compare the ability to
predict prognosis in our subtypes and those from previously published clustering
solutions.
Design, Setting, and Participants Prospective cohort study. The
cohorts were from 2 movement disorders clinics in Montreal, Quebec, Canada
(patients were enrolled during the period from 2005 to 2013). A total of 113
patients with idiopathic PD were enrolled. A comprehensive spectrum of motor and
nonmotor features (motor severity, motor complications, motor subtypes,
quantitative motor tests, autonomic and psychiatric manifestations, olfaction,
color vision, sleep parameters, and neurocognitive testing) were assessed at
baseline. After a mean follow-up time of 4.5 years, 76 patients were reassessed.
In addition to reanalysis of baseline variables, a global composite outcome was
created by merging standardized scores for motor symptoms, motor signs,
cognitive function, and other nonmotor manifestations.
Main Outcomes and Measures Changes in the quintiles of the
global composite outcome and its components were compared between different
subtypes.
Results The best cluster solution found was based on
orthostatic hypotension, mild cognitive impairment, rapid eye movement sleep
behavior disorder (RBD), depression, anxiety, and Unified Parkinson’s Disease
Rating Scale Part II and Part III scores at baseline. Three subtypes were
defined as
mainly motor/slow progression,
diffuse/malignant, and
intermediate. Despite similar age and disease duration, patients with the
diffuse/malignant phenotype were more likely to have mild cognitive impairment,
orthostatic hypotension, and RBD at baseline, and at prospective follow-up, they
showed a more rapid progression in cognition (odds ratio [OR], 8.7 [95% CI,
4.0-18.7];
P < .001), other nonmotor symptoms (OR, 10.0 [95% CI,
4.3-23.2];
P < .001), motor signs (OR, 4.1 [95% CI, 1.8-9.1];
P = .001), motor symptoms (OR, 2.9 [95% CI, 1.3-6.2];
P < .01),
and the global composite outcome (OR, 8.0 [95% CI, 3.7-17.7];
P < .001).
Conclusions and Relevance It is recommended to screen patients
with PD for mild cognitive impairment, orthostatic hypotension, and RBD even at
baseline visits. These nonmotor features identify a diffuse/malignant subgroup
of patients with PD for whom the most rapid progression rate could be
expected.