24-hour ambulatory blood pressure and cryptogenic ischemic stroke in young adults

Figures & data

Table 1. Characteristics of patients and controls included in the study.

Characteristic (no. of participants with missing data)	Patients (n = 132)	Controls (n = 106)	P
Age at the time of ABPM, y	41.9 (35.3–46.7)	41.9 (34.4–46.8)	0.913
Male sex	74 (56.1)	60 (56.6)	0.933
Low level of education (1)	64 (48.5)	40 (38.1)	0.109
Physical inactivity (4)	49 (38.0)	35 (33.3)	0.461
Diet score (4)	25 (22–29)	26 (24–30)	0.023
Obesity	72 (54.5)	47 (44.3)	0.118
Heavy alcohol use	18 (13.6)	7 (6.6)	0.079
Current tobacco smoking (1)	39 (29.8)	19 (17.9)	0.035
History of hypertension	47 (35.6)	30 (28.3)	0.231
Hypercholesterolemia	8 (6.1)	7 (6.6)	0.864
Diabetes mellitus	5 (3.8)	1 (0.9)	0.230
Cardiovascular disease	1 (0.8)	0	1.000
History of venous thrombosis	5 (3.8)	1 (0.9)	0.230
Patent foramen ovale (5)	76 (57.6)	28 (27.7)	<0.001

Data are median (interquartile range) or n (%). ABPM: ambulatory blood pressure monitoring.

Table 2. Characteristics of ambulatory blood pressure monitoring.

Characteristic (no. of participants with missing data)	Patients (n = 132)	Controls (n = 106)	P
Duration, h	23.7 (22.8–24.0)	23.7 (23.2–24.3)	0.224
Percentage of successful measurements	95.2 (90.5–98.0)	92.0 (85.8–96.0)	<0.001
Successful measurements during
the whole monitoring	60 (55–64)	60 (56–64)	0.679
daytime	43 (39–48)	44 (40–48)	0.156
nighttime	16 (14–18)	16 (14–17)	0.046
Length of nighttime, h	8.0 (8.0–9.0)	8.0 (7.0–8.7)	<0.001
Participants with poor quality of sleep during monitoring (26)	36 (29.8)	28 (30.8)	0.873
Participants on antihypertensive medication	54 (40.9)	9 (8.5)	<0.001
Number of antihypertensives per participant (in those on antihypertensive medication)	1 (1–1), 1–3	1 (1–1), 1–1	0.121
Frequency of taking antihypertensives (in those on antihypertensive medication)	1 (1–1), 1–4	1 (1–1), 1–1	0.102

Data are median (interquartile range); n (%); or median (interquartile range), range.

Table 3. Comparison of blood pressure levels between patients and controls.

	All participants (n = 238)			Participants without antihypertensives (n = 175)
BP, mm Hg	Patients (n = 132)	Controls (n = 106)	P	Patients (n = 78)	Controls (n = 97)	P
Office SBP at a baseline study visit	121 (115–132)	125 (117–135)	0.126	119 (112–128)	125 (116–134)	0.004
Office DBP at a baseline study visit	74 (68–84)	76 (68–83)	0.725	72 (66–79)	76 (68–83)	0.045
Ambulatory
24-hour SBP	117 (110–127)	122 (115–129)	0.014	115 (109–125)	121 (114–128)	0.004
24-hour DBP	75 (70–80)	77 (72–82)	0.016	72 (68–77)	77 (72–82)	0.002
daytime SBP	123 (115–132)	128 (120–134)	0.009	121 (114–129)	127 (119–133)	0.004
daytime DBP	79 (73–84)	82 (77–87)	0.002	77 (72–83)	81 (77–86)	<0.001
nighttime SBP	105 (98–116)	107 (99–114)	0.592	104 (96-110)	105 (99–113)	0.184
nighttime DBP	63 (59–72)	63 (59-69)	0.589	62 (57–68)	62 (58–68)	0.614

Data are median (interquartile range). BP: blood pressure; DBP: diastolic blood pressure; SBP: systolic blood pressure.

Table 4. Prevalence of different hypertension and non-dipping phenotypes in patients and controls.

	All participants (n = 238)			Participants without antihypertensives (n = 175)
Phenotype	Patients (n = 132)	Controls (n = 106)	P	Patients (n = 78)	Controls (n = 97)	P
24-hour hypertension	40 (30.3)	42 (39.6)	0.133	19 (24.4)	34 (35.1)	0.126
Daytime hypertension	35 (26.5)	44 (41.5)	0.015	15 (19.2)	37 (38.1)	0.007
Nocturnal hypertension	41 (31.1)	28 (26.4)	0.432	18 (23.1)	21 (21.6)	0.822
Any of the above three	49 (37.1)	49 (46.2)	0.156	22 (28.2)	41 (42.3)	0.054
Isolated nocturnal hypertension	7 (5.3)	2 (1.9)	0.305	3 (3.8)	2 (2.1)	0.657
Masked hypertension	13 (9.8)	25 (23.6)	0.004	13 (16.7)	25 (25.8)	0.146
Masked or masked uncontrolled hypertension	26 (19.7)	30 (28.3)	0.120	13 (16.7)	25 (25.8)	0.146
Uncontrolled hypertension	27 (20.5)	8 (7.5)	0.005	N/A	N/A	N/A
Hypertension by any definition	67 (50.8)	55 (51.9)	0.862	26 (33.3)	46 (47.4)	0.060
Non-dipping pattern of
SBP	37 (28.0)	17 (16.0)	0.028	16 (20.5)	16 (16.5)	0.494
DBP	25 (18.9)	5 (4.7)	0.001	10 (12.8)	3 (3.1)	0.015
SBP and/or DBP	43 (32.6)	18 (17.0)	0.006	20 (25.6)	16 (16.5)	0.137
both SBP and DBP	19 (14.4)	4 (3.8)	0.006	6 (7.7)	3 (3.1)	0.190

Data are n (%). DBP: diastolic blood pressure; N/A: not applicable; SBP: systolic blood pressure. Hypertension by any definition was defined as fulfilling the criteria for a history of hypertension and/or any criteria for hypertension on ambulatory blood pressure monitoring.

Table 5. Odds ratios and 95% confidence intervals from multivariable binary logistic regression models on the associations of non-dipping patterns of blood pressure and a dip in blood pressure with cryptogenic ischemic stroke.

Non-dipping pattern of BP/dip in BP from daytime to nighttime	All participants (n = 233)*	All participants except patients in whom antihypertensive medication was initiated between the stroke and ABPM (n = 197)^†	Participants without antihypertensives (n = 172)^‡	All participants except patients in the first tertile of the delay between the stroke and ABPM (n = 194)^§
Non-dipping pattern of
SBP	1.37 (0.62–3.02)	1.20 (0.50–2.87)	0.87 (0.34–2.26)	1.87 (0.78–4.49)
DBP	3.85 (1.20–12.42)	4.63 (1.31–16.36)	4.86 (1.07–22.02)	2.16 (0.54–8.56)
SBP and/or DBP	2.43 (1.25–4.70)	2.39 (1.16–4.90)	1.74 (0.77–3.94)	2.21 (1.07–4.56)
both SBP and DBP	4.34 (1.37–13.72)	4.17 (1.22–14.29)	2.40 (0.53–10.93)	4.85 (1.37–17.10)
10 mm Hg dip in SBP	1.16 (0.59–2.28)	0.99 (0.46–2.14)	1.37 (0.59–3.20)	0.78 (0.37–1.62)
10 mm Hg dip in DBP	0.31 (0.13–0.70)	0.33 (0.13–0.86)	0.24 (0.09–0.68)	0.58 (0.24–1.38)
10% dip in SBP	1.43 (0.58–3.53)	1.13 (0.40–3.17)	1.82 (0.59–5.60)	0.93 (0.35–2.45)
10% dip in DBP	0.36 (0.17–0.73)	0.41 (0.18–0.94)	0.31 (0.13–0.77)	0.59 (0.27–1.27)

ABPM: ambulatory blood pressure monitoring; BP: blood pressure; DBP: diastolic blood pressure; SBP: systolic blood pressure. All models are adjusted for age, sex, education, physical inactivity, diet score, obesity, heavy alcohol use, current tobacco smoking, and a history of hypertension. The models of a non-dipping pattern of SBP and the models of a dip in SBP are further adjusted for the same variable of DBP, and vice versa. No. of participants with missing data: *5 (2.1%), ^†4 (2.0%), ^‡3 (1.7%), and ^§3 (1.5%).

Table 6. Odds ratios and 95% confidence intervals from multivariable binary logistic regression models on the associations of non-dipping patterns of blood pressure and a dip in blood pressure with cryptogenic ischemic stroke (as a difference to Table 5, the confounder ‘a history of hypertension’ was replaced with ‘hypertension by any definition’.

Non-dipping pattern of BP/dip in BP from daytime to nighttime	All participants (n = 233)*	All participants except patients in whom antihypertensive medication was initiated between the stroke and ABPM (n = 197)^†	Participants without antihypertensives (n = 172)^‡	All participants except patients in the first tertile of the delay between the stroke and ABPM (n = 194)^§	Participants without hypertension by any definition (n = 114)^ǁ	Participants with hypertension by any definition (n = 119)^#
Non-dipping pattern of
SBP	1.45 (0.66–3.22)	1.26 (0.52-3.04)	0.95 (0.36–2.48)	2.12 (0.87–5.16)	0.77 (0.21–2.79)	2.12 (0.71–6.33)
DBP	4.12 (1.29–13.20)	5.15 (1.47–17.99)	5.26 (1.17–23.64)	2.17 (0.55–8.56)	8.06 (0.66–98.71)	3.88 (0.97–15.55)
SBP and/or DBP	2.66 (1.36–5.19)	2.64 (1.27–5.49)	1.95 (0.85–4.46)	2.51 (1.20–5.27)	1.46 (0.48–4.44)	4.23 (1.68–10.61)
both SBP and DBP	4.75 (1.50–15.05)	4.71 (1.38–16.08)	2.70 (0.59–12.34)	5.29 (1.49–18.70)	5.67 (0.54–60.09)	5.26 (1.33–20.84)
10 mm Hg dip in SBP	1.14 (0.58–2.25)	0.99 (0.45–2.16)	1.37 (0.59–3.22)	0.73 (0.35–1.53)	1.70 (0.55–5.28)	0.93 (0.37–2.37)
10 mm Hg dip in DBP	0.31 (0.13–0.70)	0.32 (0.12–0.83)	0.24 (0.08–0.67)	0.61 (0.25–1.47)	0.18 (0.04–0.77)	0.36 (0.12–1.04)
10% dip in SBP	1.38 (0.56–3.42)	1.15 (0.41–3.26)	1.84 (0.59–5.73)	0.86 (0.32–2.30)	2.74 (0.64–11.73)	0.90 (0.24–3.35)
10% dip in DBP	0.34 (0.17–0.70)	0.37 (0.16–0.85)	0.28 (0.11–0.70)	0.58 (0.27–1.26)	0.21 (0.06–0.72)	0.41 (0.15–1.08)

ABPM: ambulatory blood pressure monitoring; BP: blood pressure; DBP: diastolic blood pressure; SBP: systolic blood pressure. All models are adjusted for age, sex, education, physical inactivity, diet score, obesity, heavy alcohol use, and current tobacco smoking. The models of columns two to five are further adjusted for hypertension by any definition. In addition to these adjustments, the models of a non-dipping pattern of SBP and the models of a dip in SBP are further adjusted for the same variable of DBP, and vice versa. No. of participants with missing data: *5 (2.1%), ^†4 (2.0%), ^‡3 (1.7%), ^§3 (1.5%), ^ǁ2 (1.7%), and ^#3 (2.5%).

Table 7. Odds ratios and 95% confidence intervals from multivariable binary logistic regression models on the associations of non-dipping patterns of blood pressure and a dip in blood pressure with cryptogenic ischemic stroke stratified by the status of patent foramen ovale.

	All participants		All participants except patients in whom antihypertensive medication was initiated between the stroke and ABPM		All participants except patients in the first tertile of the delay between the stroke and ABPM
Non-dipping pattern of BP/dip in BP from daytime to nighttime	PFO (n = 101)*	no PFO (n = 127)^†	PFO (n = 80)^‡	no PFO (n = 112)^§	PFO (n = 83)^ǁ	no PFO (n = 106)^#
Non-dipping pattern of
SBP	1.33 (0.34–5.24)	1.55 (0.49–4.95)	1.80 (0.41–7.97)	1.10 (0.31–3.97)	1.62 (0.37–6.97)	2.32 (0.63–8.59)
DBP	3.17 (0.31–32.19)	7.37 (1.47–36.81)	2.78 (0.24–32.68)	9.58 (1.69–54.37)	1.27 (0.09–18.38)	4.03 (0.59–27.62)
SBP and/or DBP	1.52 (0.48–4.81)	4.48 (1.71–11.70)	1.72 (0.49–6.02)	3.94 (1.40–11.14)	1.19 (0.34–4.13)	3.88 (1.28–11.77)
both SBP and DBP	N/A	6.06 (1.46–25.19)	N/A	4.76 (1.02–22.17)	N/A	7.81 (1.52–40.05)
10 mm Hg dip in SBP	0.96 (0.28–3.32)	1.60 (0.60–4.29)	0.95 (0.23–3.95)	1.40 (0.47–4.12)	0.86 (0.24–3.03)	0.74 (0.23–2.34)
10 mm Hg dip in DBP	0.37 (0.08–1.68)	0.15 (0.04–0.54)	0.23 (0.04–1.50)	0.19 (0.05–0.75)	0.56 (0.12–2.77)	0.42 (0.11–1.58)
10% dip in SBP	0.93 (0.20–4.30)	2.09 (0.53–8.26)	0.81 (0.14–4.63)	1.84 (0.40–8.51)	0.86 (0.18–4.14)	0.83 (0.18–3.95)
10% dip in DBP	0.49 (0.14–1.73)	0.19 (0.06–0.57)	0.41 (0.09–1.79)	0.23 (0.07–0.80)	0.67 (0.17–2.55)	0.45 (0.14–1.45)

ABPM: ambulatory blood pressure monitoring; BP: blood pressure; DBP: diastolic blood pressure; N/A: not applicable because there were no controls with both a PFO and a non-dipping pattern of both SBP and DBP; PFO: patent foramen ovale; SBP: systolic blood pressure. All models are adjusted for age, sex, education, physical inactivity, diet score, obesity, heavy alcohol use, current tobacco smoking, and a history of hypertension. The models of a non-dipping pattern of SBP and the models of a dip in SBP are further adjusted for the same variable of DBP, and vice versa. No. of participants with missing data: *3 (2.9%), ^†2 (1.6%), ^‡2 (2.4%), ^§2 (1.8%), ^ǁ2 (2.4%), and ^#1 (0.9%). Additionally, 5 participants were excluded from all these models due to missing PFO status data.

Table 8. Selected characteristics, blood pressure levels, and different hypertension and non-dipping phenotypes of patients stratified by the delay between the stroke and ambulatory blood pressure monitoring.

Characteristic/BP, mm Hg/phenotype (no. of participants with missing data)	Patients with a delay of <9 days (n = 41)	Patients with a delay of ≥9 days (n = 91)	P
Age at the time of ABPM, y	44.0 (38.7–48.3)	40.5 (34.0–45.6)	0.004
Male sex	21 (51.2)	53 (58.2)	0.452
Physical inactivity (3)	16 (40.0)	33 (37.1)	0.752
Obesity	28 (68.3)	44 (48.4)	0.033
Heavy alcohol use	5 (12.2)	13 (14.3)	0.746
Current tobacco smoking (1)	11 (27.5)	28 (30.8)	0.706
History of hypertension	22 (53.7)	25 (27.5)	0.004
Patent foramen ovale	19 (46.3)	57 (62.6)	0.080
NIH Stroke Scale score on admission (1)	2 (1–3), 0–13	1 (0–2), 0–12	0.087
SBP at a baseline study visit	125 (118–139)	121 (114-129)	0.032
DBP at a baseline study visit	79 (72–89)	73 (67–81)	0.008
Delay between the stroke and ABPM, d	4 (3–6)	18 (12–33)	<0.001
Antihypertensive medication initiated between the stroke and ABPM	9 (22.0)	28 (30.8)	0.297
Antihypertensive medication at the time of ABPM	14 (34.1)	40 (44.0)	0.289
Ambulatory
24-hour SBP	124 (112–134)	115 (109–125)	0.006
24-hour DBP	77 (72–84)	72 (69–78)	0.007
Daytime SBP	127 (116–138)	121 (114–129)	0.011
Daytime DBP	80 (75–87)	78 (73–82)	0.044
Nighttime SBP	109 (103–125)	104 (96–110)	0.003
Nighttime DBP	70 (64–77)	62 (57–67)	<0.001
24-hour hypertension	18 (43.9)	22 (24.2)	0.022
Daytime hypertension	16 (39.0)	19 (20.9)	0.029
Nocturnal hypertension	23 (56.1)	18 (19.8)	<0.001
Any of the above three	24 (58.5)	25 (27.5)	<0.001
Isolated nocturnal hypertension	5 (12.2)	2 (2.2)	0.030
Masked or masked uncontrolled hypertension	11 (26.8)	15 (16.5)	0.167
Uncontrolled hypertension	10 (24.4)	17 (18.7)	0.452
Non-dipping pattern of
SBP	10 (24.4)	27 (29.7)	0.532
DBP	14 (34.1)	11 (12.1)	0.003
SBP and/or DBP	16 (39.0)	27 (29.7)	0.289
Both SBP and DBP	8 (19.5)	11 (12.1)	0.261
Antihypertensive medication at the time of a 3-month study visit	19 (46.3)	38 (41.8)	0.623
SBP at a 3-month study visit (7)	127 (117–139)	119 (111–127)	0.002
DBP at a 3-month study visit (7)	77 (72–85)	72 (67–79)	<0.001
Hypertensive values at three months (7)	10 (25.0)	9 (10.6)	0.036
Uncontrolled hypertension at three months (7)	7 (17.5)	7 (8.2)	0.139

Data are median (interquartile range); n (%); or median (interquartile range), range. ABPM: ambulatory blood pressure monitoring; BP: blood pressure; DBP: diastolic blood pressure; SBP: systolic blood pressure.

Data availability

The corresponding author had full access to all the data in the study and takes responsibility for its integrity and the data analysis. The data of this study may be available from the corresponding author upon reasonable request.