STAR Webinar - December 20th, 2012 Stroke POpulation Risk Tool.

STAR Webinar - December 20th, 2012

Stroke POpulation Risk Tool


What is a Stroke?


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.


Effects of a Stroke


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


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


Development Cohort (CCHS 1.1 – CCHS 3.1)


RestrictionsRisk factors available in public use filesExcluding intermediate (ex. BMI) risk factors


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


Variables


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’



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.


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


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



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


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



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.


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


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


References:

STAR Webinar - December 20th, 2012 Stroke POpulation Risk Tool.

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