Basic information
566 cases were investigated with an average age of (56.34±9.78) years. The average score of QOL was 72.69±18.10. There were 304 cases with good QOL(>72.69) and 262 cases with poor QOL(≤72.69). 253 cases had anxiety (44.7%); 192 cases had hypertension (33.9%); 113 cases had anxiety with hypertension (20.0%). The difference of QOL between the two groups was statistically significant (P<0.01). The details are shown in Table 1.
Table 1 Comparison of basic conditions of patients with different QOL (N=566)
Variables
|
Good
|
Poor
|
χ2
|
P
|
Marital status
|
|
|
0.681
|
0.409
|
Married/cohabited
|
33
|
23
|
|
|
Single /separated
|
271
|
239
|
|
|
Education level
|
|
|
4.722
|
0.094
|
Junior high school and below
|
170
|
170
|
|
|
High/Technical secondary school
|
116
|
80
|
|
|
Bachelor degree or above
|
18
|
12
|
|
|
Monthly income (RMB)
|
|
|
6.112
|
0.047
|
<2000
|
78
|
62
|
|
|
2000-4000
|
163
|
164
|
|
|
>4000
|
63
|
36
|
|
|
Habitation
|
|
|
3.636
|
0.057
|
Rural
|
199
|
191
|
|
|
Urban
|
105
|
71
|
|
|
Hypertension
|
|
|
56.254
|
<0.001
|
No
|
243
|
131
|
|
|
Yes
|
61
|
131
|
|
|
Stage of cancer
|
|
|
5.034
|
0.081
|
Ⅰ
|
163
|
122
|
|
|
Ⅱ
|
61
|
73
|
|
|
Ⅲ+Ⅳ
|
80
|
67
|
|
|
BMI
|
|
|
11.391
|
0.001
|
<24
|
178
|
189
|
|
|
≥24
|
126
|
73
|
|
|
Anxiety symptoms
|
|
|
144.458
|
<0.001
|
No
|
239
|
74
|
|
|
Yes
|
65
|
188
|
|
|
PSS
|
|
|
61.869
|
<0.001
|
Low/Moderate
|
49
|
122
|
|
|
High
|
255
|
140
|
|
|
Notes: “Good” includes “fairly good” and “very good”, “Bad” includes “fairly bad” and “very bad” responses.
Multivariate logistic regression analysis of the factors affecting the QOL
Taking the QOL as the dependent variable, the variables with P<0.1 in the single factor were included in the multiple logistic regression. The results showed that the factors that entered the equation were monthly income (RMB), hypertension, anxiety, and social support. Monthly income >4000 yuan and social support were the protective factors for the QOL, and hypertension and anxiety were the risk factors for the QOL. The details were shown in Table 2.
Table 2 Multiple logistic regression analysis of QOL
Factors
|
B
|
S.E.
|
Wald χ2
|
P
|
OR
|
95%CI
|
Monthly income (RMB)
|
|
|
|
|
|
|
2000-4000 v s<2000
|
-0.068
|
0.283
|
0.058
|
0.810
|
0.934
|
0.537-1.625
|
>4000 vs 2000
|
-0.890
|
0.367
|
5.889
|
0.015
|
0.411
|
0.200-0.843
|
BMI
|
-0.078
|
0.223
|
0.123
|
0.726
|
0.925
|
0.597-1.433
|
Hypertension
|
1.229
|
0.221
|
30.888
|
<0.001
|
3.419
|
2.216-5.273
|
Anxiety
|
1.945
|
0.230
|
71.584
|
<0.001
|
6.994
|
4.457-10.975
|
PSS
|
-0.692
|
0.242
|
8.189
|
0.004
|
0.501
|
0.312-0.804
|
Constant
|
-0.832
|
0.389
|
4.575
|
0.032
|
0.435
|
|
Calculation of additive interaction index of anxiety and hypertension on QOL
As shown in Table 3, 113 patients (20.0%) were anxiety with hypertension. The reference were no anxiety and no hypertension. The OR value of hypertension without anxiety on QOL was 3.112 (95%CI:1.778-5.447); The OR value of anxiety without hypertension on QOL was 7.978 (95%CI:4.939-12.886); The OR value of hypertension and anxiety on QOL was 32.327 (95%CI: 16.848-62.026). The interaction between anxiety and hypertension was significant. The relative excess risk ratio (RERI) was 22.238 (95%CI:44.119-88.596); the attribution ratio (AP) was 0.688 (95%CI:0.234-1.142); The interaction index (S) was 3.466 (95%CI: 0.823-14.435). AP was 0.688, indicating that 68.8% of the patients with poor QOL due to the interaction between anxiety and hypertension.
Table 3 Analysis of interaction between anxiety symptoms and hypertension on QOL
Anxiety
|
Hypertension
|
QOL
|
β
|
P
|
OR/RR
|
95%CI
|
Good
|
Poor
|
-
|
-
|
192
|
42
|
-
|
|
|
|
-
|
+
|
47
|
32
|
1.135
|
<0.001
|
3.112
|
1.778-5.447
|
+
|
-
|
51
|
89
|
2.077
|
<0.001
|
7.978
|
4.939-12.886
|
+
|
+
|
14
|
99
|
3.476
|
<0.001
|
32.327
|
16.848-62.026
|
RERI
|
|
|
|
|
|
22.238
|
44.119-88.596
|
AP
|
|
|
|
|
|
0.688
|
0.234-1.142
|
S
|
|
|
|
|
|
3.446
|
0.823-14.435
|
Correlations among continuous variables
As shown in Table 4, anxiety was negatively correlated with QOL and PSS, and positively correlated with BP (P<0.01). BP was negatively correlated with PSS and QOL (P<0.01). PSS was positively correlated with QOL (P<0.01 ).
Table4 Correlations among study variables
Variables
|
Mean±SD
|
1
|
2
|
3
|
4
|
Anxiety
|
47.43±14.45
|
|
|
|
|
BP
|
124.94±23.25
|
0.140**
|
|
|
|
PSS
|
68.11±12.12
|
-0.539**
|
-0.246**
|
|
|
QOL
|
72.69±18.10
|
-0.473**
|
-0.349**
|
0.560**
|
1
|
Notes: **P<0.01.QOL: quality of life, PSS: perceived social support, BP: blood pressure.
Hierarchical regression analysis
As shown in Table 5, age, monthly income (RMB), and BMI were added in the first step. In the second block, anxiety and PSS were added. Finally, the PSS&Anxiety interaction term were added in the last block. The PSS&Anxiety interaction term was negatively correlated with QOL (β=-0.219, P<0.01), and explained an extra 4.0% of the variance (F= 68.649, Adjusted R2=0.399, ΔR2=0.040, P<0.01); The PSS&BP interaction term was not associated with QOL (β=0.013, F=55.138, Adjusted R2=0.365, ΔR2=0.001, P=0.730).
Table5 Hierarchical linear regression for anxiety symptoms and PSS with quality of life
Variables
|
Quality of Life
|
Block 1
|
Block 2
|
Block 3
|
Age
|
0.052
|
0.021
|
0.004
|
Monthly income (RMB)
|
0.057
|
0.101**
|
0.082*
|
BMI
|
0.110**
|
-0.026
|
-0.047
|
Anxiety
|
|
-0.256**
|
-0.220**
|
PSS
|
|
0.430**
|
0.373**
|
PSS&Anxiety
|
|
|
-0.219**
|
F
|
3.546*
|
64.673**
|
63.459**
|
Adjusted R2
|
0.013
|
0.360
|
0.399
|
ΔR2
|
0.019
|
0.347
|
0.040
|
Notes: *P<0.05, **P<0.01.
Simple slope analysis
In Figure 1, simple slope analysis showed that the association between anxiety and QOL was gradually decreased in the low (-1SD below the mean, B=0.110, β=0.093, P<0.05), mean (B=-0.269, β=-0.229, P<0.01) and high (+1SD above the mean, B=-0.648, β=-0.552, P<0.01) groups of PSS.