Differing Demographics of Vascular Parkinsonism and Idiopathic Parkinson’s Disease
Karthik Sarma MDResident PGY4
Shreyansh Shah MD and William Ondo MDDept of Neurology
14th April, 2011 63rd AAN Annual Meeting, Hawaii, 2011.
Disclosures
• Anand K Sarma, MD• Shreyansh D Shah, MD
• William G Ondo, MD
No disclosures
No disclosures
W. Ondo: Grant Support: Ipsen, Acadia, Bayer, Takeda, Allergan, PSG, HSG, IMPAX
Speaking / Consulting fees: GSK, Allergan, Novartis, Ipsen, TEVA, UCB Pharma, Merz, Lundbeck
Vascular Parkinsonism
• Critchley introduced the term in 1929• Initially used to describe clinical presentations
consisting of…rigidityshort-stepping gaitfixed facies pyramidal, pseudobulbar signs and cerebellar signsdementia and urinary incontinence
• Variously referred to as Lower Body Parkinsonism, Arteriosclerotic Pseudo-Parkinsonism, etc.
Features of VP• Clinical
Typically older age of onset Shorter duration of symptoms at presentation Symmetric gait difficulties No rest tremor
• Imaging Typically chronic small vessel ischemic changes
• Pathology Absence of Lewy body pathology
Imaging
Source: BCM imaging database
Diagnosing VP
• No consensus diagnostic criteria available• Diagnostic problem in the community especially
when non-neurologists and non-movement disorders experts involved in making the diagnosis of Parkinsonian symptoms
• Several criteria proposed including: Vascular Rating Scale by Winikates and Jankovic Loeb and Gandolfo’s modification of Hachinski score Zijlmans et al criteria for VP
Epidemiology of idiopathic PD
• Age of the patient considered as one of the most important risk factors for development of PD
AGE α RISK of PD
• Studies have revealed that both Incidence and Prevalence increase with age
Prevalence studies
Incidence of PD
Incidence and distribution of parkinsonism in Olmsted County, Minnesota, 1976-1990.Bower JH, Maraganore DM, McDonnell SK, Rocca WA.Neurology. 1999 Apr 12;52(6):1214-20.
Age- and sex-specific average annual incidence rates (per 100,000 person-years) of parkinsonism and its types: Olmsted County, MN, 1976–1990*
Question…
Does the misdiagnosis of VP as PD increase the age of onset of PD in epidemiologic studies?
Hypothesis
VP misdiagnosed as PD would cause the average age at symptom onset of PD to increase, altering the age related distribution of PD and hence the epidemiology of PD.
The incidence of PD in the population follows a bell shaped (normal) distribution about a median age of 60 years.
Study Methods
• Queried the PDCMDC database for the last 100 consecutive active patients with a diagnosis of VP and PD each.
• Collected demographic information including age at symptom onset, risk factors, clinical and radiological features.
• Examined entire database for diagnoses ratio.• Calculated how VP would alter epidemiology of
PD if labeled as PD.
Results
Diagnosis No. of Patients Mean Age at Sx Onset
VP without overt stroke 81 74.07
VP with overt stroke 17 71.29
All VP 98 (31F) 73.59
PD 102 (37F) 57.81
No. of VP charts examined: 108 Diagnosis changed after initial assignment: 10 Total No. of VP considered for analysis: 98 The difference of the mean age at symptom onset between VP with and without overt stroke was not significantly different, p = 0.34
Results continued
VP PD p value *
Mean age in years at presentation (SD) 77.12 (6.58) 63.4 (12.22) <0.0001
Mean age in years at symptom onset
(SD)73.1 (7.62) 57.8 (11.22) <0.0001
*- using Mann Whitney U test
Early Clinical Features: Comparison
Prominent Symptom VP (%) PD (%) p value*
Bradykinesia 16 24 0.22
Tremor 13 70 <0.0001
Gait 87 13 <0.0001
RBD 3 0 0.116
UE symptoms 3 0 0.116
* Chi Square test
Prominent Clinical Features at Presentation
%Patients
Clinical features
Risk Factors: ComparisonRisk Factor VP (%) PD (%) p value*
HTN 59 41 0.016
Smoking 35 23 0.044
HLD 32 27 0.356
CAD 29 15 0.016
DM 23 16 0.212
Afib 10 2 0.017
TIA 9 4 0.158
Stroke 17 1 <0.0001
PVD 1 1 1
Carotid Dz 1 2 1
No known risk 16 35 0.006
* Chi Square test
Risk Factors: ComparisonRisk Factor VP (%) PD (%) p value*
HTN 59 41 0.016
Smoking 35 23 0.044
HLD 32 27 0.356
CAD 29 15 0.016
DM 23 16 0.212
Afib 10 2 0.017
TIA 9 4 0.158
Stroke 17 1 <0.0001
PVD 1 1 1
Carotid Dz 1 2 1
No known risk 16 35 0.006
* Chi Square test
Risk Factors
% Patients
Vascular Risk Factors
Imaging Characteristics
% Patients
Age wise distribution of Onset of Symptoms
% Patients
Age Groups in years Age Groups in years
Caveats of extrapolating the results to predict age of onset for “PD”…
• Sample of 200 patients may not be a representative sample of the database
• Patient sample and database may not be representative of the population
• Obvious recruitment bias at a Parkinson’s Disease center
• Relative occurrence of VP and PD in the population are not similar to database
But if we did extrapolate…
VP PD Total
Study Patient Nos. 98 102 200
Mean age at onset of symptoms in
Study73.59 57.81
Database Patient Nos. 805 6937 7742
Does VP misdiagnosed as PD increase the average age at onset of PD?
Mean Age at Onset for PD would increase from: 57.81 to 59.36
[ 73.59 * 805 / 7742 ] + [ 57.81 * 6937 / 7742 ]= 59.36
Proportional weighting based on relative occurrence
Value of study
• Provides a possible explanation for variability in epidemiology trials of age of onset for PD and more commonly, falsely elevated ages
• Encouraged future studies such as the ongoing sorting of our entire database
• Demands a population based incidence study differentiating VP and PD
• Importance of differentiating the two in the community given disparate pathophysiology, progression, response to treatment, prognosis and importantly, person making the diagnosis.
Acknowledgements
I would like to thank my friend and colleague, Yogeshwar V Kalkonde for his valuable input and help.
View of Waikiki sunset from my room.Karthik Sarma; 9th April, 2011.
Questions?
Thank you!
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