The study involved 244 adult hypertensive patients having followed at TASH cardiac or renal clinics. The mean age of the cohort was 59.4 years, and 54% of subjects were female. Significant proportion of patient had comorbidities with 29 % of patients having diabetes, 56% dyslipidemic or on statin therapy, and 16 % having IHD. Majority of patients (65%) were taking more than 1 anti-hypertensive drug (Table 1).
Table 1. Baseline demographic data
PARAMETER
|
Number of Patients
|
percentage of Patients
|
total patients
|
244
|
|
Mean Age (years)
|
59.4 years
|
|
Females
|
132
|
54%
|
Type of anti-hypertensive
|
|
|
CCB
|
150
|
61.5
|
ACEI
|
147
|
60.2
|
ARB
|
19
|
7.8
|
HCT
|
63
|
25.8
|
BB
|
75
|
30.7
|
Other anti-HTN
|
21
|
8.6
|
Number of anti-hypertensives
|
|
|
1
|
83
|
34
|
2
|
91
|
37
|
3
|
55
|
23
|
4
|
13
|
5
|
5
|
1
|
.4
|
COMORBIDITY
|
NUMBER
|
PERCENT
|
DIABETES
|
70
|
28.7
|
DYSLIPIDEMIA
|
136
|
55.7
|
STROKE
|
5
|
2
|
IHD
|
38
|
15.6
|
Baseline laboratory and imaging data from echocardiography, doppler ultrasound of peripheral vessels and electrocardiogram revealed the extent of comorbidities and hypertension mediated target organ damage (Table 2).
Table 2. Baseline laboratory and imaging parameters
Parameter
|
N
|
Minimum
|
Maximum
|
Mean
|
Std. Deviation
|
creat
|
114
|
0.6
|
11
|
.97
|
1.132
|
fbs
|
165
|
60
|
413
|
123.39
|
44.754
|
hga1c
|
56
|
4
|
138
|
9.20
|
17.594
|
tc
|
164
|
100
|
321
|
170.51
|
48.632
|
ldl
|
155
|
26
|
238
|
120.66
|
40.721
|
hdl
|
168
|
18
|
96
|
46.79
|
11.545
|
tg
|
167
|
42
|
469
|
133.98
|
68.772
|
sv1_rv5_6
|
5
|
1
|
4
|
2.80
|
1.095
|
ravl
|
5
|
1
|
3
|
1.40
|
.894
|
ivs_thickness
|
124
|
6
|
16
|
11.32
|
2.207
|
BP control was suboptimal as shown from the mean of both OBP 137 (19)/81 (10) mmHg and 24‑h ABP 137 (16)/81 (10) mmHg. Rates of controlled BP were 58.6% for OBP, 45.1% for mean 24‑h ABPM and only 21.7 % for mean night time BP (Table 3).
Table 3. Results of ABPM and OBPM
|
sample
|
min
|
max
|
Mean
|
SD
|
Office SBP
|
244
|
90
|
200
|
137.52
|
19.058
|
|
|
|
|
|
|
Office DBP
|
244
|
60
|
120
|
81.30
|
10.929
|
Mean 24hr DBP
|
244
|
60
|
120
|
80.95
|
10.371
|
mean_day_SBP
|
244
|
102
|
198
|
135.45
|
17.576
|
mean_day_DBP
|
244
|
60
|
120
|
79.30
|
11.075
|
mean_night_SBP
|
244
|
100
|
198
|
138.41
|
16.247
|
mean_night_DBP
|
244
|
62
|
125
|
84.09
|
11.546
|
maximum 24hr SBP
|
244
|
113
|
260
|
191.00
|
30.145
|
Maximum 24hr DBP
|
244
|
66
|
130
|
114.44
|
10.836
|
minimum_24_SBP
|
244
|
80
|
225
|
100.36
|
16.355
|
Minim_24_DBP
|
244
|
60
|
127
|
64.37
|
8.519
|
The proportion of patients with controlled BP was different as per the office and ambulatory blood pressure recordings. This proportion also differs based on the period of the ABPM studied for both sexes (Table 4).
Table 4. Proportion of controlled ABPM and OBPM by sex
Parameter
|
Male
|
Female
|
total
|
Number (total=244)
|
OBP controlled
|
59.8
|
57.6
|
58.6
|
143
|
24hr controlled
|
42%
|
47%
|
45.1
|
110
|
Day time controlled
|
53.6%
|
58.3
|
56.1
|
137
|
Night time controlled
|
19.6
|
23.5
|
21.7
|
53
|
Correlation studies done using Pearson product-moment correlation coefficient revealed significant correlation of age, and OBP values with ABPM values.
The relationship between age and diastolic BP was investigated using Pearson product-moment correlation coefficient. Preliminary analyses were performed to ensure no violation of the assumptions of normality, linearity and homoscedasticity. There was a Small, negative correlation between the two variables, r = –.0.21, n = 244, p < .001, with increasing age associated with lower DBP Levels.
An independent-samples t-test was conducted to compare the ABPM results for males and females. There was no significant difference in mean ABPM values between males (24 hr SBP = 137(14)/82(10) and females (24 hr SBP = 136(17)/80(11); t (242) = 0.46, p = .65, two-tailed). The magnitude of the differences in the means (mean difference = .95, 95% CI: –3.10 to 5.01) was non significant.
Comparison between patients with and without Comorbidities showed significant difference in ABPM measurements.
- Diabetics had higher 24hr systolic ABPM values compared to non diabetics (Diabetic 24hr SBP = 141(17)/81(12) vs non diabetic (24 hr SBP = 134(15)/80(10); t (241) = 2.8, p = .005, two-tailed). The magnitude of the differences in the means (mean difference =6 .5, 95% CI: 1.99 to 10.99) was significant. Similar results were seen for day and night SBP but not DBP.
- Dyslipidemia patients had significantly higher systolic ABPM . dyslipidemic pt 24 hr SBP = 139(17)/81(10) vs non dyslipidemics (24 hr SBP = 134(14)/80(10); t (241) = 2.2, p = .029, two-tailed). The magnitude of the differences in the means (mean difference =4.5, 95% CI: 0.4 to 8.6) was significant. Similar result was seen for day time SBP but not night SBP or DBP.
- Patients with IHD also had poorer 24 hr systolic ABPM control (IHD patients 24 hr SBP = 142(18)/82(8) compared to patients without IHD (24 hr SBP = 136(16)/81(11); t (242) = 2.0, p = .046, two-tailed). The magnitude of the differences in the means (mean difference = 5.7, 95% CI: 0.1 to 11.4) was significant. Similar result was seen for day time SBP but not night SBP or DBP.
ABPM values were compared based on Type of anti-hypertesive drugs patient used. ARB users had poor day time SBP and DBP control. Day time ABPM in ARB users SBP = 147(23)/87(14) vs patients without IHD (24 hr SBP = 134(17)/78(10); t (242) = 3.0, p = .003, two-tailed). The magnitude of the differences in the means (mean difference SBP = 12.5, 95% CI: 1.1 to 24 and DBP Mean = 8.2 95% CI= 1.2-15.2) was significant. Subgroups were compared based on the Number of anti-hypertensive medications they used by the one way analysis of variance test and no difference was seen.
Patients with controlled OBP status had better ABPM values compared with those having uncontrolled OBP.
Chi square test for independence with Yates’ Continuity Correction was done to compare groups with respect to control status of their ABPM measurements as per the current guidelines.
A chi-square test for independence (with Yates’ Continuity Correction) indicated no significant association between gender and ABPM control status, χ2 (1, n = 244) = .59, p = .44, phi = –.058. Office BP values showed medium correlation with ABPM; the strongest positive correlation was seen between office DBP and mean night DBP , r = –.0.35, n = 244, p < .001, with increasing Office DBP associated with HIGHER mean night DBP Levels.
OBPM control status had statistically significant but small degree of association of with 24hr ABPM control status (χ2 (1, n = 244) = 9.8, p = .002, phi = .021.), but was not correlated with night BP control status (Table 5).
Table 5. Correlation and Discrepancy between ABPM and OBP control
Parameter
|
Controlled OBP
|
UnControlled OBP
|
P value
|
Phi
|
Controlled 24 hr ABP
|
53.8 %
|
32%(White coat effect)
|
=0.002
|
0.21
|
Uncontrolled 24 hr ABP
|
46.2% (masked uncontrolled BP)
|
68%
|
|
|
Kappa measure of agreement showed Weak correlation between OBP and 24 HR ABPM control status(kappa=0.2 with p<0.001). OBP was able to predict controlled BP as per 24 HR ABPM with sensitivity of 70% and specificity of 50%.
Among the comorbidities, DM was inversely related with 24hr ABPM control status, χ2 (1, n = 244) = 10.6, p =0 .005, phi = 0.20, albeit to a small degree. Other comorbidities had no significant correlation with ABPM status. The class of anti – hypertensive drug used by patients had no significant correlation with ABPM control status.