STAR Webinar - December 20th, 2012
Stroke POpulation Risk Tool
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What is a Stroke?
STAR Webinar - December 20th, 2012
Table 1 Ranking and number of deaths for the 10 leading causes of death, Canada, 2000 and 2009
2000 2009 Cause of death
rank number percent rank number percent
All causes of death ... 218,062 100.0 ... 238,418 100.0
Total, ten leading causes of death ... 175,149 80.3 ... 182,139 76.4
Malignant neoplasms (cancer) 1 62,672 28.7 1 71,125 29.8
Diseases of heart (heart disease) 2 55,070 25.3 2 49,271 20.7
Cerebrovascular diseases (stroke) 3 15,576 7.1 3 14,105 5.9
Chronic lower respiratory diseases 4 9,813 4.5 4 10,859 4.6
Accidents (unintentional injuries) 5 8,589 3.9 5 10,250 4.3
Diabetes mellitus (diabetes) 6 6,714 3.1 6 6,923 2.9
Alzheimer's disease 7 5,007 2.3 7 6,281 2.6
I nfluenza and pneumonia 8 4,966 2.3 8 5,826 2.4
I ntentional self-harm (suicide) 9 3,606 1.7 9 3,890 1.6
Nephritis, nephrotic syndrome and nephrosis (kidney disease)
10 3,136 1.4 10 3,609 1.5
All other causes ... 42,913 19.7 ... 56,279 23.6 ...not applicable Note: The order of the causes of death in this table is based on the ranking of the 10 leading causes of death in 2009.
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Effects of a Stroke
STAR Webinar - December 20th, 2012
Stroke Prediction Models
Framingham USA 1971 - 1974
Score Australian 1988 - 2003
Interstroke 22 Countries 2007 - 2010
Qrisk England-Wales 1993 – 2008
SPoRT Canada 2000 - 2006
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Development CohortCCHS 1.1 32,848 Sep 2000/Nov 2001CCHS 2.1 33,679 Jan 2003 / Jan
2004CCHS 3.1 33,402 Jan 2005 / Jan
2006
Linked to Ontario health administration data until March 31, 2012.
Registered Person DatabaseCIHI/DAD
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Development Cohort (CCHS 1.1 – CCHS 3.1)
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RestrictionsRisk factors available in public use filesExcluding intermediate (ex. BMI) risk factors
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Competing RiskThe type of failure that prevents the observation or fundamentally alters the probability of the occurrence of the event of interest .
Death is a competing risk for stroke
OutcomeDiagnostic codes for stroke were taken
from Canadian Stroke Network
Time to stroke
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Variables
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Risk Factor CategoriesRisk Behaviour Category DefinitionSmoking Heavy smoker Daily current smoker (≥1 pack/day)
Light smoker Daily current smoker (<1 pack/day)Former smoker Former daily smoker
Non-smoker Former occasional smoker or never smokerAlcohol Heavy drinker >24 (men) or >17 (women) drinks/week in
previous month or at least one binging in a weekModerate drinker 5 to 24 (men) or 3 to 17 (women) drinks/weekLight drinker 0 to 4 (men) or 0 to 2 (women) drinks/week
Occasional drinker <1 drink/monthCurrent non-drinker No alcohol consumption in the last 12 months
Physical activity Inactive 0 to <1.5 METs/day Moderately active 1.5 to <3 METs/day
Active ≥3 METs/dayDiet Poor diet Weekly vegetable serving <7
Fair diet 7 <= Weekly vegetable serving <14
Adequate diet 14 <= Weekly vegetable servingStress
Very high stress Self-perceived stress: ‘quite a bit’ or ‘extremely’
Somewhat stress Self-perceived stress: ‘a bit’Low stress Self-perceived stress: ‘not at all’ or ‘not very’
STAR Webinar - December 20th, 2012
STAR Webinar - December 20th, 2012
Univariate AnalysisRisk Factors and Categories Male Female
Smoking HR (95% CI) HR (95% CI)
Heavy 1.55 (1.17,2.04) 2.20 (1.71,2.84)Light 1.41(1.07,1.84) 1.67 (1.36,2.05)
Former 1.16 (0.98,1.41) 1.02 (0.87,1.2)Non-smoker Ref. Ref.
AlcoholHeavy drinker 1.25 (0.93,1.70) 1.12 (0.59,2.13)
Moderate drinker Ref. Ref.Light drinker 0.99 (0.81,1.21) 1.10 (0.88,1.38)
Occasional drinker 1.09 (0.84,1.44) 1.20 (0.95, 1.52)
Current non-drinker 1.18 (0.95,1.47) 1.43 (1.16,1.76)
Physical activityInactive 1.28 (1.05,1.56) 1.25 (1.02,1.54)
Moderately active 1.21 (0.96,1.51) 1.04 (0.82,1.32)Active Ref. Ref.
DietPoor 1.54 (1.25,1.90) 1.43 (1.18,1.73)Fair 1.25 (1.03,1.52) 1.25 (1.06,1.46)
Adequate Ref. Ref.Stress
Very high 1.22 (0.98,1.52) 1.40 (1.16,1.69)Somewhat 1.06 (0.90,1.26) 1.04 (0.90,1.22)
Low Ref. Ref.
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The Index Risk Factors and Categories Male Female
Smoking HR (95% CI)Index Score
HR (95% CI)Index Score
Heavy 1.55 (1.17,2.04) 3 2.20 (1.71,2.84) 4Light 1.41(1.07,1.84) 2 1.67 (1.36,2.05) 3
Former 1.16 (0.98,1.41) 1 1.02 (0.87,1.2) 1Non-smoker Ref. 0 Ref. 0
AlcoholHeavy drinker 1.25 (0.93,1.70) 1 1.12 (0.59,2.13) 2
Moderate drinker Ref. 0 Ref. 0Light drinker 0.99 (0.81,1.21) 0 1.10 (0.88,1.38) 1
Occasional drinker 1.09 (0.84,1.44) 0 1.20 (0.95, 1.52) 1
Current non-drinker 1.18 (0.95,1.47) 1 1.43 (1.16,1.76) 2
Physical activityInactive 1.28 (1.05,1.56) 2 1.25 (1.02,1.54) 1
Moderately active 1.21 (0.96,1.51) 1 1.04 (0.82,1.32) 0Active Ref. 0 Ref. 0
DietPoor 1.54 (1.25,1.90) 2 1.43 (1.18,1.73) 2Fair 1.25 (1.03,1.52) 1 1.25 (1.06,1.46) 1
Adequate Ref. 0 Ref. 0Stress
Very high 1.22 (0.98,1.52) 1 1.40 (1.16,1.69) 2Somewhat 1.06 (0.90,1.26) 0 1.04 (0.90,1.22) 0
Low Ref. 0 Ref. 0
Models
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Model Assessment
Male Female
C-stat (95% CI) 0.85 (0.83 – 0.86) 0.87 (0.85 – 0.88)
75/25 14.1 14.95/95 152.5 197.3# O-P > 20% 5/53 3/51
STAR Webinar - December 20th, 2012
STAR Webinar - December 20th, 2012
STAR Webinar - December 20th, 2012
STAR Webinar - December 20th, 2012
Development Cohort (CCHS 4.1)
Female Male Overall
Records 15573 13032 28605
Years follow up 65629 54558 120187
# strokes in overall follow-up
114 104 218
Development Cohort
Overall Male Female n=82259 n=37483 n=44776
Mea
n SE Mean SE Mean SE
Age 48.9 0.0583 48.20.0836
6 49.4 0.0809Gender
Male 45.60.0017
4
Female 54.40.0017
4
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Validation cohortOverall Male Female
n= 28605 n=13032 n=15573
Mea
n SEMea
n SEMea
n SE
Age50.6
20.099
3 50.20.144
9 51.00.136
3Gender
Male45.5
60.002
9
Female54.4
40.002
9
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STAR Webinar - December 20th, 2012
Diagnostic codesDiagnostic codes for stroke were taken from Canadian Stroke Network definition as
362, 3623, 430, 431, 435, 436 for ICD-9 and
G45, H340, H34.1, I60, I61, I63, I64 excluding I608, I636, and G454 for ICD-10.
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References:Let’s talk about stroke. Heart & Stroke
foundationBéland Y. Canadian Community Health Survey.
Methodological overview. Health Reports, Vol. 13, No. 3, March 2002
OHIP Eligibility, Ontario Ministry of Health and Long Term Care. 9-23-2009. 7-21-2011. Ref Type: Online source
Pintilie M. Dealing with competing risks: testing covariates and calculating sample size. Stat Med 2002; 21 : 3317-3324
Melberg T, Nyg+Ñrd OK, Kuiper KK-J, Nordrehoug JE. Competing risk analysis of events 10 years after revascularization. Scand Cardiovasc J 2010; 44; 279-288
Walter, Kremers, Concordance for survival time data: Fixed and time-dependent covariates and possible ties in predictor and time. Technical report series #80. April 2007.
http://www.openmedicine.ca/article/view/483/459 Claudia SanMartin
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References:
Statistical evaluation of prognostic versus diagnostic models: Beyond the ROC curve
Tripepi, G., Statistical methods for the assessment of prognostic biomarkers (part II); calibration and reclassification. Nephrol. Dial. Transplant 2010 May 25 (5): 1402-5 Epub 2010 Feb 18
Handbook of constructing composite indicators, OECD http://www.oecd.org/std/leadingindicatorsandtendencysurveys/42495745.pdf
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References: