Association Between Blood Pressure Indicators and Stroke in Aged Population: A Community-Based Nested Case-Control Study

Figures & data

Table 1 Characteristics of Study Participants

Characteristics	Case Participants (n=415, %)		Control Participants (n=415, %)	P-value
Sociodemographic and behavioral features
Age (years)	69.59±5.77		68.99±5.58	0.128
BMI	24.84±3.63		24.80±3.38	0.878
SBP (mmHg)	146.16±20.47		137.21±20.30	<0.001
DBP (mmHg)	79.99±12.03		78.04±11.60	0.018
PP (mmHg)	66.17±17.56		59.17±17.01	<0.001
MAP (mmHg)	102.05±12.95		97.77±12.76	<0.001
PPI	0.45±0.08		0.43±0.08	<0.001
TG (mmol/L)	1.53±1.00		1.49±0.85	0.545
TC (mmol/L)	4.83±0.96		4.82±0.96	0.890
LDL-C (mmol/L)	2.88±0.90		2.90±0.86	0.716
HDL-C (mmol/L)	1.31±0.34		1.41±0.39	<0.001
HbA1c (%)	6.06±0.96		6.05±1.00	0.857
FBG (mmol/L)	5.75±1.37		5.80±1.50	0.682
Smoking	103(24.8)		125(30.1)	0.051
Drinking	20(4.8)		33(8.0)	0.044
High salt diet	3(0.7)		2(0.5)	0.500^a
Regular physical exercise	131(31.6)		177(42.7)	0.001
Medical history
Hypertension		333(80.2)	218(52.5)	<0.001
Diabetes		94(22.7)	57(13.7)	0.001
Dyslipidemia		72(17.3)	40(9.6)	0.001
Coronary heart disease		193(46.5)	84(20.2)	<0.001
Medications
Antihypertensive		272(65.5)	171(41.2)	<0.001
Antidiabetic		71(17.1)	39(9.4)	0.001
Lipid lowering drugs		31(7.5)	14(3.4)	0.007

Notes: The variables with normal distribution were expressed as the mean± SD. Categorical variables were presented as number of patients (column percentage). ^aFisher’s exact probability test.

Abbreviations: BMI, body mass index; WHR, waist hip ratio; SBP, systolic blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; MAP, mean arterial pressure; PPI, pulse pressure index; TG, triglyceride; TC, total cholesterol; LDL-C, Low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; HbA1C, glycated hemoglobin; FBS, fasting blood glucose.

Table 2 Relationship Between Different Blood Pressure Indicators and the Risk of Stroke

Variables	AOR	95% CI	P-value
SBP (mmHg)	1.02	1.02–1.03	<0.001
Normal (<140)	–		Reference
Stage I (140–160)	1.60	1.15–2.23	0.006
Stage II (160–180)	2.26	1.435–3.56	<0.001
Stage III (>180)	16.71	3.79–73.66	<0.001
DBP (mmHg)	1.01	0.99–1.03	0.068
Normal (<90)	–		Reference
Stage I (90–100)	2.01	1.29–3.14	0.002
Stage II (100–110)	2.32	0.96–5.59	0.061
Stage III (>110)	0.45	0.09–2.25	0.333
PP (mmHg)	1.03	1.02–1.04	<0.001
First quartile (<50)	–		Reference
Second quartile (50–60)	1.80	1.19–2.75	0.006
Third quartile (61–73)	1.43	0.94–2.17	0.099
Fourth quartile (>73)	3.71	2.39–5.78	<0.001
MAP (mmHg)	1.02	1.01–1.04	<0.001
First quartile (<91)	–		Reference
Second quartile (91–100)	0.85	0.55–1.30	0.440
Third quartile (100–108)	1.66	1.08–2.55	0.020
Fourth quartile (>108)	2.14	1.38–3.30	0.001
PPI	25.68	3.19–206.90	0.002
First quartile (<0.39)	–		Reference
Second quartile (0.39–0.44)	0.78	0.51–1.19	0.248
Third quartile (0.44–0.49)	1.78	1.17–2.71	0.007
Fourth quartile (>0.49)	1.74	1.14–2.66	0.010

Notes: The variables that indicated P<0.05 in Table 1 were selected into the logistic regression model for assessment of each blood pressure indicators correlated with stroke. SBP and DBP were formed into four categories according to Guidelines for the prevention and treatment of hypertension in China 2017. PP, MAP and PPI were categorized into quartiles from the lowest to the highest value. Multivariate model-controlled baseline HDL-C level, drinking history, regular physical exercise, medical history and medications.

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; MAP, mean arterial pressure; PPI, pulse pressure index.

Figure 1 Nomogram constructed from baseline related indicators.

Notes: To calculate participants’ stroke incident probability, points for each parameter are assigned by corresponding values from the “Points” axis, and sum of the points is plotted on “Total points” axis. The stroke incident probability is the value at a vertical line from corresponding total points.

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; MAP, mean arterial pressure; PPI, pulse pressure index.

Figure 2 Internal calibration plots of nomogram calibration curves for each blood pressure indicators: (A) SBP, (B) DBP, (C) MAP, (D) PP, and (E) PPI.

Notes: The 45°line represents a perfect match between the actual survival outcome (y-axis) and nomogram-predicted survival (x-axis). Closer distance from the points to the 45°line indicates higher prediction accuracy.

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; MAP, mean arterial pressure; PPI, pulse pressure index.

Figure 3 Forest plots for different SBP and PP conditions.

Notes: SBP was formed into normal group and abnormal group according to 140mmHg, PP was formed into group according to 50mmHg. Multivariate model-controlled baseline HDL-C level, drinking history, regular physical exercise, medical history and medications.

Abbreviations: AOR, adjusted odds ratio; SBP, systolic blood pressure; PP, pulse pressure.