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Table 2 Characteristics of the original research studies included in the systematic review

From: Hormonal contraceptives and risk of ischemic stroke in women with migraine: a consensus statement from the European Headache Federation (EHF) and the European Society of Contraception and Reproductive Health (ESC)

Study

Population

Design

Sample size

Study period

Outcome of interest

Exposure

Diagnostic criteria for migraine

Confirmation of stroke diagnosis

Type of hormonal contraceptive

Quality of evidence (ACCP)

Collaborative Group, 1975 [33]

Women with stroke aged 15–44 years

Hospital-based, case-control

430 strokes, 429 hospital controls, 451 neighborhood controls

1969–71

Ischemic stroke

Migraine vs no migraine

Interview; no ICHD

Yes

Estrogen ≥50 μg

C

Tzourio, 1995 [18]

Women with stroke aged <45 years

Hospital-based, case-control

72 strokes, 173 controls

1990–93

Ischemic stroke

Migraine vs no migraine

Questionnaire; ICHD

Yes

Estrogen 50 μg (14.6%), 30–40 μg (73.8%), 20 μg (6.8%), progestogen only (4.8%)

C

Lidegaard, 1995 [36]

Women aged 15–44 years

Hospital-based, case-control

497 ischemic strokes, 1396 controls

1985–1989

Ischemic stroke

Migraine vs no migraine, HC use vs non-use

Questionnaire; no ICHD

No

Estrogen 50 μg (4.5%), 30–40 μg (11.0%), progestogen only (1.5%), unspecified (1.6%)

C

Schwartz, 1998 [34]

Women with stroke aged 18–44 years

Hospital-based, case-control

373 strokes, 1191 controls

1991–95

Ischemic stroke

Migraine vs no migraine

Interview; no ICHD

Yes

Estrogen <50 μg

C

Chang, 1999 [11]

Women with stroke aged 20–44 years

Hospital-based, case-control

291 strokes, 736 controls

1990–94

Ischemic stroke

Migraine vs no migraine

Questionnaire; ICHD

Yes

Estrogen ≥50 μg and <50 μg (stratified data)

C

Milhaud, 2001 [38]

Women with ischemic stroke

Hospital-based, cohort

3502 ischemic strokes (130 migraineurs)

1979–98

NA

NA

Interview; ICHD

Yes

Not specified

C

Nightingale, 2004 [37]

Women aged 15–49 years

Hospital-based, case-control

190 strokes, 1129 controls

1992–1998

Ischemic stroke

Migraine vs no migraine, HC use vs non-use

Administrative code (GPRD); no ICHD

Yes

Not specified

C

MacClellan, 2007 [17]

Women with ischemic stroke aged 15–49 years

Hospital-based, case-control

386 ischemic strokes, 614 controls

2001–03

Ischemic stroke

Migraine with aura vs no migraine

Questionnaire; ICHD

Yes

Not specified

C

Pezzini, 2011 [39]

Subjects with ischemic stroke aged ≤45 years

Hospital-based, cohort

981 strokes (235 migraineurs, 50.6% women)

2000–09

NA

NA

Interview; ICHD

Yes

Not specified

C

Kurth, 2016 [2]

Women aged 25–42 years at baseline

Prospective, cohort

115,541 women

1989–2011

Stroke

Migraine with and without aura vs no migraine

Questionnaire; ICHD

No

Not specified

B

Albieri, 2016 [35]

Subjects aged 25–80 years (subanalysis in women aged 25–50 years)

Retrospective, cohort

49,711 ischemic strokes

2003–2011

Stroke

Triptan prescription

Administrative code (triptan prescription); No ICHD

No

Not specified

C

Champaloux, 2017 [10]

Women aged 15–49 years

Population-based, case-control

25,887 ischemic strokes

2006–2012

Ischemic stroke

Migraine with or without aura vs no migraine

Administrative code (ICD-9-CM); Nno ICHD

 

Not specified

C

  1. NA indicates not applicable; GPRD indicates General Practice Research Database; HC indicates hormonal contraceptives; ICD-9-CM indicates International Classification of Diseases, Ninth Revision, Clinical Modification; ICHD indicates International Classification of Headache Disorders