Covariates of non-dipping and elevated night-time blood pressure in ischemic stroke patients: the Norwegian Stroke in the Young Study*

Figures & data

Table 1. Clinical characteristics of the total study population and groups according to their dipping status.

	Overall population	Dipping	Non-dipping	p
		(n = 167)	(n = 101)
Age (years)	49 ± 10	48 ± 10	50 ± 10	0.170
Male gender	68	63	76	<0.05
Smoking	50	47	55	0.230
Metabolic syndrome	34	35	32	0.596
Obesity	25	22	31	0.070
Body mass index (kg/m^2)	27.2 ± 4.9	26.8 ± 4.8	27.5 ± 4.5	0.259
Diabetes mellitus	12	8	14	<0.05
Antidiabetic treatment	7	5	10	0.164
Hypertension	44	35	55	<0.01
Antihypertensive treatment	26	19	32	<0.05
Hypercholesterolemia	61	63	58	0.229
Clinic SBP (mmHg)	133 ± 18	131 ± 18	136 ± 18	0.060
Clinic DBP (mmHg)	81 ± 10	80 ± 10	82 ± 10	0.250
PWV (m/s)	7.8 ± 1.9	7.6 ± 1.7	8.2 ± 2.2	0.002
High for age PWV	16	10	26	<0.01
Mean cIMT (mm)	0.8 ± 0.2	0.8 ± 0.2	0.9 ± 0.3	<0.05
Carotid plaque	9	8	12	0.268
Creatinine (μmol/l)	76 ± 32	72 ± 14	83 ± 49	<0.05
Total cholesterol (mmol/l)	5.4 ± 1.2	5.4 ± 1.2	5.5 ± 1.3	0.610
HDL cholesterol (mmol/l)	1.4 ± 0.5	1.4 ± 0.5	1.3 ± 0.4	0.20
LDL cholesterol (mmol/l)	3.6 ± 1.1	3.6 ± 1.0	3.7 ± 1.1	0.452
Triglycerides (mmol/l)	1.6 ± 1.0	1.6 ± 1.1	1.6 ± 0.8	0.650
Fasting blood glucose (mmol/l)	5.7 ± 1.4	5.5 ± 1.1	5.9 ± 1.5	<0.05
HbA1c (%)	5.8 ± 0.9	5.6 ± 0.8	6.0 ± 1.2	0.110

Data are shown as mean ± SD or percentage.

SBP: systolic blood pressure; DBP: diastolic blood pressure; PWV: pulse-wave velocity; cIMT: carotid intima–media thickness; HDL: high-density lipoprotein; LDL: low-density lipoprotein; Hb_A1c: glycosylated hemoglobin.

Table 2. Ambulatory blood pressure (BP) measurements of the total study population and groups according to their dipping status.

	Overall population	Dipping	Non-dipping	p
		(n = 167)	(n = 101)
Day-time SBP (mmHg)	122 ± 14	123 ± 13	122 ± 16	0.684
Day-time DBP (mmHg)	80 ± 9	80 ± 8	79 ± 10	0.674
Day-time mean BP (mmHg)	94 ± 10	94 ± 9	94 ± 11	0.920
Day-time heart rate (beats/min)	78 ± 11	79 ± 10	75 ± 11	0.011
Night-time SBP (mmHg)	108 ± 16	103 ± 13	116 ± 17	< 0.001
Night-time DBP (mmHg)	70 ± 9	67 ± 8	76 ± 9	< 0.001
Night-time mean BP (mmHg)	83 ± 11	79 ± 9	89 ± 11	< 0.001
Night-time heart rate (beats/min)	65 ± 10	65 ± 10	66 ± 11	0.667
Elevated night-time BP	51	33	80	< 0.001
24 h SBP (mmHg)	120 ± 14	119 ± 13	121 ± 16	0.250
24 h DBP (mmHg)	78 ± 8	77 ± 8	79 ± 9	0.150
24 h mean BP (mmHg)	91 ± 10	90 ± 9	93 ± 11	0.104
24 h heart rate (beats/min)	75 ± 10	76 ± 10	74 ± 11	< 0.05

Data are shown as mean ± SD or percentage.

SBP: systolic blood pressure; DBP: diastolic blood pressure.

Table 3. Univariate predictors of non-dipping and elevated night-time blood pressure (BP).

	Non-dipping		Elevated night-time BP
	OR (95% CI)	p	OR (95% CI)	p
Age (years)	1.02 (0.99–1.05)	0.178	1.04 (1.01–1.06)	<0.01
Male gender	1.86 (1.05–3.27)	<0.05	2.83 (1.64–4.87)	<0.001
Body mass index (kg/m^2)	1.03 (0.97–1.08)	0.301	1.13 (1.06–1.20)	<0.001
Clinic SBP (mmHg)	1.01 (0.99–1.03)	0.062	1.04 (1.02–1.06)	<0.001
Clinic DBP (mmHg)	1.02 (0.99–1.04)	0.253	1.09 (1.06–1.13)	<0.001
Waist (cm)	1.01 (0.99–1.03)	0.299	1.04 (1.02–1.07)	<0.001
Weight (kg)	1.02 (0.99–1.03)	0.063	1.04 (1.02–1.06)	<0.001
Obesity	1.59 (0.90–2.81)	0.108	3.45 (1.87–6.36)	<0.001
Diabetes mellitus	1.96 (0.88–4.37)	0.100	2.50 (1.05–5.94)	<0.05
24 h mean BP (mmHg)	1.02 (0.99–1.05)	0.089	1.23 (1.17–1.31)	<0.001
Antihypertensive treatment	2.09 (1.15–3.79)	<0.05	3.42 (1.78–6.55)	<0.001
PWV (m/s)	1.18 (1.03–1.34)	<0.05	1.26 (1.09–1.45)	<0.01
High for age PWV	3.00 (1.53–5.91)	<0.01	2.82 (1.37–5.79)	<0.01
HDL cholesterol (mmol/l)	0.73 (0.44–1.22)	0.231	0.50 (0.30–0.84)	<0.01
Fasting blood glucose (mmol/l)	1.22 (0.99–1.50)	0.054	1.40 (1.10–1.78)	<0.01
Creatinine (μmol/l)	1.02 (1.01–1.04)	<0.01	1.03 (1.01–1.05)	<0.01
Mean cIMT (mm)	2.48 (0.97–6.30)	0.057	7.98 (2.57–24.81)	<0.001
Carotid plaque	1.63 (0.69–3.85)	0.268	3.01 (1.15–7.90)	<0.05

SBP: systolic blood pressure; DBP: diastolic blood pressure; PWV: pulse-wave velocity; HDL: high-density lipoprotein; cIMT: carotid intima–media thickness; OR: odds ratio; CI: confidence interval.

Table 4. Independent covariates of non-dipping blood pressure (BP) pattern in multivariate logistic regression analysis.

	OR	95% CI	p
High for age PWV	2.12	1.07–4.19	0.031
Antihypertensive treatment	1.45	0.81–2.59	0.208
Serum creatinine (μmol/l)	1.02	0.99–1.03	0.059
Male gender	1.19	0.65–2.19	0.576

PWV: pulse-wave velocity; OR: odds ratio; CI: confidence interval.

Figure 1. Higher night-time mean blood pressure (BP) was associated with (a) higher mean carotid intima–media thickness (IMT) and (b) higher carotid–femoral pulse-wave velocity (PWV).

Table 5. Independent covariates of elevated night-time blood pressure (BP) in multivariate logistic regression analysis.

	OR	95% CI	p
Mean cIMT (mm)	3.83	1.01–14.50	<0.05
Male gender	2.84	1.47–5.47	<0.01
Obesity	3.31	1.59–6.89	<0.01
Non-dipping	7.41	3.92–14.03	<0.001
Antihypertensive treatment	1.70	0.70–3.64	0.171
High for age PWV	1.29	0.52–3.23	0.581

cIMT: carotid intima–media thickness; PWV: pulse-wave velocity; OR: odds ratio; CI: confidence interval.