Comparison of worldwide First-ever-in-a-lifetime (FES) stroke incidence risk: implications for

current and future stroke incidence

Syme, P.D., Byrne, A., Chen, R., Finlayson, A.

Aims To determine the contribution of stroke incidence risk to crude incidence

Methods 18 worldwide incidence studies were compared with the Scottish Borders stroke study (SBSS) Studies were selected if they fulfilled “ideal” incidence criteria and data was available on first-ever stroke (FES) numbers, the population denominator for each age group and the study duration

Methods cont. Logistic regression was used along with age standardisation to estimate risk

An SBSS crude incidence prediction model was developed

The SBSS model was tested on the Scottish National dataset (110,000,000 person years of risk) for FES and admissions. The model was then tested on Australian National dataset for stroke admissions

Comparison of age standardisation and odds ratio estimation of age-adjusted risk

Res

idu a

ls (

Age

-adj

u ste

d in

c ide

nce

risk)

Worldwide risk of stroke (all ages)

Stu

dyNW England

Dijon London

ESPRO

All UKFredericksberg

Arcadia

Tees Aukland

SEPIVAC NEMESIS

OCSPPerth

RochesterBelluno

Inherred Valle D'Aosta

SoderhamnNovosibirsk

Age and sex-adjusted Odds Ratio (95% CI)

1.81.61.41.21.0.8.6.4

UK studies

SBSS

Worldwide risk of stroke in < 65 years old

Stu

dyDijon

NWEngland Inherred

All UK<65ESPRO

Vallle D'Aosta

Arcadia LondonAukland

OCSPPerth

Fredericksberg

Soderhamn SEPIVAC

Tees Belluno

NEMESIS

Rochester Novosibirsk

Age and sex-adjusted Odds Ratio (95% CI)

3.02.52.01.51.0.50.0

UK studies

SBSS

Worldwide incidence risk

Auc

k 81

Roc

85-

8N

ovo

OC

SP

Per

thLo

ndon

d'A

osta

ES

Pro

Dijo

nT

ees

NW

Eng

NE

ME

SIS

Bel

luno

SB

SS

SE

PIV

AC

Innh

erre

Sod

89-

9A

rcad

iaF

red

89-0

10

20

30

40

50

60

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

(n/1

0000

)

OR

World incidence studies

% aged 65 years and over

crude incidence (n/10000) Odds ratio (OR) Odds ratio <65

Worldwide incidence risk

Au

ck 8

1

Ro

c 8

5-8

No

vo

OC

PS

Pe

rth

Lo

nd

on

d'A

ost

a

ES

Pro

Dijo

nT

ee

s

NW

En

gN

EM

ES

ISB

ellu

no

SB

SS

SE

PIV

AC

Inn

he

rre

So

d 8

9-9

Arc

ad

ia

Fre

d 8

9-

0

10

20

30

40

50

60

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

(n/1

0000

)

OR

World incidence studies

% aged 65 years and over

crude incidence (n/10000) Odds ratio (OR)

Odds ratio 65 years and over

Change in incidence risk

Odds ratios

Res

idua

ls (

Age

-adj

uste

d in

cide

nce

risk)

Odds ratio estimation of age-adjusted risk

Scottish First-ever strokes

(SMR1) from 1981- 2000

Scottish First-ever stroke 1981-2000

percentage of the population >= 65 years old

18161412108

Sco

ttish

Firs

t-ev

er s

trok

e (n

)3000

2000

1000

0

-1000

Western Is

Tayside

Lothian

Lanark

Glas

Gramp

Forth V

Fife

D & G

Bord

A & A

A & C

SBSS estimation of first-ever stroke(SMR1 returns 1981-2000)

SBSS predicted first-ever stroke male or female

120010008006004002000

1600

1400

1200

1000

800

600

400

200

0

-200

Western Is

Tayside

Shetland

Orkney

Lothian

Lanark

Highland

Glas

Gramp

Forth V

Fife

D & G

Bord

A &A

A &C

TotalPopulationRsq = 0.9701

Firs

t-ev

er

stro

ke n

um

bers

(n)

Western Is

Tayside

Lothian

Lanark

Glas

Gramp

Forth V

Fife

D & G

Bord

A & A

A & C

Rsq=0.97

Scottish stroke admissions

(SMR1) from 1981- 2000 Scottish Stroke Admissions 1981-2000

percentage of the population >= 65 years old

18161412108

Sco

ttish

Str

oke

Adm

issi

ons

(n)

5000

4000

3000

2000

1000

0

-1000

Western Is

Tayside

Lothian

Lanark

Glas

Gramp

Forth V

Fife

D & G

Bord

A & A

A & C

SBSS estimation of admissions (SMR1 returns 1981-2000)

SBSS estimated First-ever stroke

3000200010000

Sco

ttish

Str

oke

Adm

issi

ons

(n)

4000

3000

2000

1000

0

Western Is

Tayside

Lothian

Lanark

Glas

Gramp

Forth V

Fife

D & G

Bord

A & A

A & C

Rsq= 0.97

SBSS FES model tested on Australian stroke admissions for 1999

Australian cerebrovascular admissions

SBSS estimated First-ever stroke

120001000080006000400020000

Aus

tral

ian

Str

oke

Adm

issi

ons

(n)

14000

12000

10000

8000

6000

4000

2000

0

NT

ACT

Tas

SA

WA

Qld

Vic

NSW

Total Population

Rsq = 0.9912

Predicted First-ever stroke/year

2000 2025 2050

Male Female Both Male Female Both Male Female Both

UK 63,293 68,041 131,334 93,119 91,461 184,580 111,921 108,740 220,661

Europe 678,373 822,599 1,500,972 99,9005 1,107,013 2,106,018 1,234,753 1,332,148 2,566,900

USA 242,783 253,026 495,809 451,123 436,857 887,980 589,360 571,817 1,161,177

World 3,220,191 286,2318 6,082,510 6,177,150 5,671,623 11,848,773 10,842,281 10,180,342 21,022,623

Conclusions

• We have demonstrated significant differences in age-adjusted stroke incidence risk worldwide

• Incidence risk has not declined over the last 20 years of incidence studies

• For most populations, crude incidence can be accurately estimated by age-dependent incidence

• We predict a massive increase in stroke incidence over the next 50 years due to population ageing