Subtypes of masked hypertension and target organ damage in untreated outpatients

Figures & data

Figure 1. Distribution of subtypes of hypertension (A) and masked hypertension (B). Values are number of patients (% of the corresponding total). MHT: masked hypertension.

Table 1. Characteristics of the participants by subtype of masked hypertension.

Characteristic	Normotension	Isolated daytime MHT	Isolated night-time MHT	Day-night MHT	p Value
	(n = 550)	(n = 123)	(n = 78)	(n = 471)
Demographic characteristics
Age, y	54.1 ± 10.3	48.8 ± 10.5*	51.7 ± 9.8^†	49.3 ± 9.7*^‡	<0.001
Male sex, n (%)	186 (33.8)	71 (57.7)*	40 (51.3)*	277 (58.8)*	<0.001
Body mass index, kg/m²	23.9 ± 3.3	24.6 ± 2.6*	24.7 ± 2.7*	24.8 ± 3.0*	<0.001
Smokers, n (%)	53 (9.7)	22 (17.9)*	15 (19.2)*	113 (24.0)*	<0.001
Alcohol drinkers, n (%)	63 (11.5)	32 (26.0)*	17 (21.8)*	120 (25.5)*	<0.001
Diabetes mellitus, n (%)	31 (5.6)	4 (3.3)	5 (6.4)	13 (2.8)	0.088
Clinic BP, mmHg
Systolic	123.4 ± 9.8	127.6 ± 7.3*	126.1 ± 7.6*	129.1 ± 6.7*^‡	<0.001
Diastolic	74.6 ± 6.9	80.5 ± 5.4*	79.6 ± 4.8*	82.2 ± 5.1*^†‡	<0.001
Ambulatory BP, mmHg
24-H systolic	116.1 ± 7.3	126.0 ± 7.0*	124.7 ± 5.7*	131.8 ± 8.9*^†‡	<0.001
24-H diastolic	73.2 ± 5.0	81.3 ± 3.8*	81.2 ± 2.8*	86.3 ± 4.7*^†‡	<0.001
Daytime systolic	122.7 ± 8.4	136.9 ± 8.8*	126.3 ± 5.5*^†	138.4 ± 9.6*^‡	<0.001
Daytime diastolic	77.6 ± 5.9	88.7 ± 5.3*	82.4 ± 3.1*^†	90.9 ± 5.6*^†‡	<0.001
Night-time systolic	103.7 ± 9.0	105.4 ± 6.4	117.3 ± 7.9*^†	119.6 ± 9.9*^†‡	<0.001
Night-time diastolic	64.6 ± 6.2	66.7 ± 3.1*	75.8 ± 4.3*^†	77.5 ± 5.5*^†‡	<0.001
24-h pulse rate, bpm	70.4 ± 7.5	74.0 ± 7.2*	72.5 ± 7.5*^†	74.9 ± 7.8*^‡	<0.001
Serum measurements, mmol/L
Fasting glucose	5.07 ± 0.82	4.91 ± 0.56*	4.91 ± 0.65	5.00 ± 0.71	0.078
Total cholesterol	5.16 ± 0.94	5.07 ± 0.91	4.91 ± 0.87*	5.09 ± 0.93	0.110
HDL cholesterol	1.62 ± 0.44	1.50 ± 0.37*	1.45 ± 0.38*	1.45 ± 0.37*	<0.001
LDL cholesterol	2.93 ± 0.86	2.94 ± 0.79	2.82 ± 0.78	2.97 ± 0.83	0.528
Triglycerides	1.23 (0.90–1.70)	1.24 (0.87–1.65)	1.30 (0.90–1.87)	1.34 (0.95–1.79)*	0.093

Values are arithmetic mean ± SD or geometric mean (interquartile range) or number of subjects (percentage of the column total). BP: blood pressure; HDL: high-density lipoprotein; LDL: low-density lipoprotein; MHT: masked hypertension. Vs. normotension, *p < 0.05, vs. isolated daytime MHT, ^†p < 0.05; vs. isolated night-time MHT, ^‡p < 0.05.

Table 2. Unadjusted and adjusted means of target organ damage indices by subtype of masked hypertension.

Measurements	Adjustment	Normotension	Isolated daytime MHT	Isolated night-time MHT	Day-night MHT	p Value
Cf-PWV, m/s (n = 1222)	Unadjusted	7.58 ± 0.05	7.73 ± 0.11	7.59 ± 0.14	7.77 ± 0.06*	0.086
	Adjusted	7.51 ± 0.05	7.86 ± 0.11^†	7.58 ± 0.13	7.82 ± 0.05^‡	<0.001
Carotid IMT, μm (n = 1188)	Unadjusted	623.7 ± 4.24	623.8 ± 8.91	640.1 ± 11.17	624.6 ± 4.60	0.584
	Adjusted	611.3 ± 3.86	638.1 ± 7.87^†	639.8 ± 9.64^†	634.3 ± 4.13^‡	<0.001
LVMI, g/m² (n = 904)	Unadjusted	80.0 ± 0.75	77.9 ± 1.61	79.2 ± 2.15	81.0 ± 0.81	0.347
	Adjusted	79.6 ± 0.76	79.1 ± 1.57	77.9 ± 2.08	81.4 ± 0.81	0.216
E/E’ (n = 901)	Unadjusted	9.92 ± 0.12	9.49 ± 0.25	10.12 ± 0.34	9.78 ± 0.13	0.349
	Adjusted	9.63 ± 0.12	9.91 ± 0.24	10.09 ± 0.32	10.06 ± 0.12*	0.078
eGFR, ml/min/1.73 m^2	Unadjusted	117.9 ± 1.11	116.8 ± 2.37	119.7 ± 2.96	119.6 ± 1.21	0.607
(n = 1218)	Adjusted	116.8 ± 1.09	117.8 ± 2.23	119.8 ± 2.74	120.7 ± 1.17*	0.119
Urinary ACR, mg/mmol	Unadjusted	0.62 (0.58‒0.67)	0.59 (0.51‒0.69)	0.77 (0.63‒0.92)*	0.69 (0.64‒0.75)*	0.041
(n = 1222)	Adjusted	0.58 (0.56‒0.60)	0.65 (0.61‒0.70)	0.79 (0.72‒0.87)^†	0.74 (0.71‒0.77)^‡	<0.001

Values are mean ± standard error or geometric mean (95% confidence interval). In adjusted models, age, sex, body mass index, 24-h pulse rate, current smoking, alcohol drinking, serum fasting glucose and total cholesterol were considered as covariables. Abbreviations: ACR, albumin-to-creatinine ratio; Cf-PWV, carotid-femoral pulse wave velocity; IMT, intima-media thickness; LVMI, left ventricular mass index; MHT, masked hypertension. Comparison with the normotension group, *p < 0.05, ^†p < 0.01, ^‡p < 0.001.

Figure 2. Fully adjusted means of target organ damage indices according to the subtype of masked hypertension. The differences in cfPWV (A), carotid IMT (B), LVMI (C), E/E’ (D), eGFR (E) and urinary ACR (F) among patients with normotension, isolated daytime MHT, isolated night-time MHT and day-night MHT were compared using the analysis of covariance method. Means were adjusted for age, sex, body mass index, 24-h heart rate, smoking, alcohol drinking, serum total cholesterol and fasting glucose, and office systolic and diastolic blood pressure. ACR: albumin to creatinine ratio; cfPWV: carotid-femoral pulse wave velocity; IMT: intima-media thickness; LVMI: left ventricular mass index; MHT: masked hypertension. Compared to normotension, ∗p < 0.05, ^†p < 0.01, ^‡p < 0.001.

Table 3. Multivariate-adjusted correlation of target organ damage indices with daytime and night-time blood pressures.

Target organ damage	Systolic blood pressure, mmHg		p Value	Diastolic blood pressure, mmHg		p Value
	Daytime	Night-time		Daytime	Night-time
cfPWV, m/s (n = 1222)	0.24 (0.18, 0.29)^‡	0.20 (0.15, 0.26)^‡	0.38	0.04 (−0.02, 0.09)	0.08 (0.02, 0.14)^†	0.30
Carotid IMT, μm (n = 1188)	0.15 (0.09, 0.20)^‡	0.13 (0.08, 0.19)^‡	0.79	0.05 (−0.01, 0.11)	0.06 (0.00. 0.12)*	0.85
LVMI, g/m^2 (n = 904)	0.08 (0.02, 0.15)*	0.11 (0.04, 0.17)^‡	0.62	0.07 (0.00, 0.13)*	0.09 (0.03, 0.16)^†	0.61
0.11 (0.04,0.17)^†	0.10 (0.04, 0.17)^†	E/E’ (n = 901)	0.97	0.07 (0.01, 0.14)*	0.08 (0.01, 0.14)*	0.96
eGFR, ml/min/1.73 m^2 (n = 1218)	0.04 (−0.02, 0.10)	0.07 (0.02, 0.13)*	0.45	0.04 (−0.02, 0.09)	0.04 (−0.02, 0.10)	0.93
Urinary ACR, mg/mmol (n = 1222)	0.10 (0.04, 0.16)^‡	0.13 (0.07, 0.18)^‡	0.52	0.11 (0.05, 0.16)^‡	0.14 (0.08, 0.20)^‡	0.40

Values are partial correlation coefficient (r) with 95% confidence interval (CI) in the parentheses. Covariates in adjusted model included age, sex, body mass index, 24-h pulse rate, smoking, alcohol drinking, serum glucose, and serum total cholesterol. p values are for the comparison between daytime and night-time blood pressures. Significance of the partial r, *p < 0.05, ^†p < 0.01, ^‡p < 0.0001. For abbreviations, please refer to the footnotes of Table 2.