We aimed to examine the prevalence of lower-extremity peripheral artery disease (LE-PAD) and its associated factors in 3,128 Chinese hypertensive adults 45 to 75 years old without known cardiovascular disease, PAD, chronic kidney disease, diabetes, and dyslipidemia. A cross-sectional investigation was carried out in a rural area of Lianyungang, China. An ankle–brachial index ≤0.90 in either leg was used to define LE-PAD. Prevalence of LE-PAD was 9.0% (10.0% in women and 7.4% in men). In the multivariable logistic regression model, odds ratios (95% confidence interval) of having LE-PAD, were 1.82 (1.27 to 2.61) for participants 65 to 75 versus 45 to 55 years old, 1.48 (1.00 to 1.20) for participants with a waist circumference ≥90 versus <90 cm, 1.47 (1.05 to 2.04) and 1.62 (1.15 to 2.27) for participants with grade 2 and 3 hypertension versus controlled blood pressure or grade 1 hypertension, 1.35 (1.00 to 1.83) and 1.61 (1.16 to 2.23) for participants with heart rate at rest 70 to 80 and ≥80 versus <70 beats/min, and 1.41 (1.00 to 1.97) for participants with poor versus good sleeping quality. For other risk factors, gender-related differences were observed. Adjusted odds ratios of having LE-PAD for men and women were 1.07 (0.66 to 1.74) and 0.65 (0.47 to 0.90) for inland versus coastal residents and 1.03 (0.57 to 1.86) and 1.62 (1.09 to 2.41) for participants with body mass index ≥25 versus <25 kg/m 2 . In conclusion, there was a high prevalence of LE-PAD in Chinese hypertensive adults without known cardiovascular disease, PAD, chronic kidney disease, diabetes, and dyslipidemia, particularly in women in coastal areas and in participants with higher heart rate and poor sleeping quality. Therefore, ankle–brachial index determinations should be encouraged in clinical practice in Chinese hypertensive adults.
Patients with symptomatic or asymptomatic lower-extremity peripheral artery disease (LE-PAD) have a significantly increased risk for premature mortality and cardiovascular events. The primary noninvasive test for diagnosis of LE-PAD is the ankle–brachial index (ABI) at rest, and typically an ABI ≤0.90 is used to define LE-PAD. Numerous studies have identified hypertension as 1 of the major risk factors for LE-PAD. In recent guidelines for the management of hypertension, presence of LE-PAD based on ABI measurement has been listed as a prognostic factor for risk stratification to be used in planning hypertension management. This study aimed to examine the prevalence of LE-PAD and its associated factors in Chinese hypertensive adults 45 to 75 years old without known cardiovascular disease, PAD, chronic kidney disease, diabetes, and dyslipidemia in a rural area of Lianyungang, Jiangsu Province, China. As such, our results may reveal a high underlying risk of cardiovascular disease burden owing to LE-PAD in Chinese hypertensive adults.
Methods
The study subjects were participants of the ongoing China Stroke Primary Prevention Trial (CSPPT). CSPPT is a multicenter randomized controlled trial designed to study if enalapril maleate and folic acid tablets combined is more effective in preventing stroke in patients with hypertension compared to enalapril maleate alone. Details regarding inclusion/exclusion criteria, treatment assignment, and outcome measurements of the trial have been described elsewhere ( http://clinicaltrials.gov/ct2/show/NCT00794885 ). In this study we included subjects from Lianyungang who participated in the screening phase of the CSPPT.
Briefly, we conducted a community-based screening in 20 townships within 2 counties (Ganyu, which is coastal, and Donghai, which is inland) in Lianyungang from October 2008 to September 2009. The inclusion criteria were (1) age 45 to 75 years and (2) seated systolic blood pressure (SBP) ≥140 mm Hg and/or seated diastolic blood pressure (DBP) ≥90 mm Hg at the 2 screening visits (with ≥24 hours between visits) or currently under antihypertension treatment. Participants were excluded if they reported a history of myocardial infarction, stroke, heart failure, cancer, or serious mental disorders or if they were unwilling to participate in the survey. This study was approved by the ethics committee of the Institute of Biomedicine, Anhui Medical University, Hefei, China. Written informed consent was obtained from each participant before data collection.
Baseline data collection was conducted by trained research staff according to a standard operating procedure. Each participant was interviewed using a standardized questionnaire designed specifically for the study. The question about standard of living was phrased as “How does your standard of living compare to others?” and a choice of 3 responses (poor, medium, and good) was provided. The question about physical activity was phrased as “How do you describe your daily physical activity level?” and a choice of 3 responses (low, moderate, and high) was provided. The question about sleeping quality was phrased as “How do you describe your sleeping quality?” and a choice of 3 responses (poor, medium, and good) was provided. The question about meat consumption was phrased as “Do you eat meat (red meat) frequently (count the yearly averaged weekly intake times of meat consumption)?” and a choice of 4 responses regarding weekly intake (<1 time, 1 to 2 times, 3 to 5 times, and ≥5 times) was provided. The question about fruit and green vegetable consumption was phrased as “How much fruit and green vegetables do you eat (count the yearly averaged weekly intake of fruits and green vegetables)?” and a choice of 3 responses regarding weekly intake (<1 jin [<500 g], 1 to 3 jin [500 to 1,500 g], and ≥3 jin [≥1,500 g]) was provided.
Anthropometric measurements including height, weight, and waist circumference were taken using a standard operating procedure. Height was measured without shoes to the nearest 0.1 cm on a portable stadiometer. Weight was measured in light indoor clothing without shoes to the nearest 0.1 kg. Body mass index (BMI) was calculated as weight (kilograms) divided by height (meters) squared. Waist circumference was measured as the minimum circumference between the inferior margin of the rib cage and the crest of the ileum.
Seated BP measurements were obtained by trained research staff after subjects had been seated for 10 minutes using a mercury manometer with the standard method of calibration and appropriately sized cuffs according to a standard operating procedure. Triplicate measurements on the same arm were taken with ≥2 minutes between readings. Heart rates at rest were measured by pulse palpation (for ≥30 seconds) after the third measurement. Each patient’s SBP and DBP were calculated as the mean of the 3 independent measurements. The BP measured at visit 2 was used for analysis.
The ABI was calculated for each leg by dividing the SBP obtained at the ankle level in the respective leg by the SBP of the brachial artery. Participants rested ≥10 minutes before measurements were made. Measurements were performed with the participants in the supine position using the Omron Colin BP-203RPE VP-1000 device (Omron Health Care, Kyoto, Japan), which has well-documented validity and reproducibility. The lowest value of the ABI was used in the analysis. Measurements in all subjects were carried out by a trained technician using a standard protocol. An ABI ≤0.90 in either leg was used to define LE-PAD.
Hypertension was categorized into 3 grades: grade 1, SBP 140 to 159 and/or DBP 90 to 99 mm Hg; grade 2, SBP 160 to 179 and/or DBP 100 to 109 mm Hg; grade 3, SBP ≥180 and/or DBP ≥110 mm Hg. Treated hypertension was defined as receiving antihypertensive medication within the previous 2 weeks. Current smoking was defined as having smoked ≥1 cigarette/day or ≥18 packs in the previous year. Current drinking was defined as drinking alcohol ≥2 times per week in the previous year.
Means and proportions were calculated for the population characteristics by gender. Differences in population characteristics were compared using Student’s t test or chi-square test. Adjusted odds ratios and 95% confidence intervals of having LE-PAD were determined from multivariable logistic regression models that included age group (45 to 54, 55 to 64, and 65 to 75 years), gender, cigarette smoking, alcohol drinking, antihypertensive treatment status (treated and untreated), hypertension grades (controlled blood pressure or grade 1, 2, and 3), BMI (≥25 vs <25 kg/m 2 ), waist circumference (≥90 vs <90 cm), heart rate (<70, 70 to 80, and ≥80 beats/min), sleeping quality (poor, medium, and good), geographic region (coastal and inland), standard of living (poor, medium, and good), meat consumption (<1 time, 1 time to 2 times, and ≥3 times/week), fruit and green vegetable consumption (<1 jin [<500 g], 1 to 3 jin [500 to 1,500 g], and ≥3 jin [≥1,500 g]/week), education level (illiterate, primary level, elementary or higher levels), and physical activity level (low, moderate, and high). All statistical analyses were performed in SAS 8.2 (SAS Institute, Cary, North Carolina).
Results
Overall 3,495 participants 45 to 75 years old with hypertension had valid measurements of ABI. In this report, study participants with cardiovascular disease (n = 98), chronic kidney disease (n = 17), PAD (n = 4), diabetes (n = 118), dyslipidemia (n = 103), cancer (n = 11), or with any missing data (n = 16) regarding antihypertensive treatment status, age, gender, height, weight, waist circumference, smoking status, drinking status, standard of living, education and physical activity levels, sleeping quality, and heart rate were excluded. Our final analysis included 3,128 participants. No participants had an ABI >1.40.
Population characteristics by gender are listed in Table 1 . Men had statistically significant higher values for age, DBP, cigarette smoking, alcohol drinking, standard of living, red meat consumption, sleeping quality, and education levels and lower values for SBP, BMI, and antihypertensive treatment compared to women.
| Variable | Total (n = 3,128) | Men (n = 1,236) | Women (n = 1,892) | p Value |
|---|---|---|---|---|
| Age (years) | 59.2 ± 7.5 | 59.9 ± 7.6 | 58.8 ± 7.4 | <0.001 |
| Age group (years) | ||||
| 45–55 | 989 (31.6%) | 355 (28.7%) | 634 (33.5%) | <0.001 |
| 55–65 | 1,346 (43.0%) | 520 (42.1%) | 826 (43.7%) | |
| 65–75 | 793 (25.4%) | 361 (29.2%) | 432 (22.8%) | |
| Systolic blood pressure (mm Hg) | 167.2 ± 20.5 | 165.3 ± 20.8 | 168.5 ± 20.2 | <0.001 |
| Diastolic blood pressure (mm Hg) | 95.2 ± 12.0 | 97.0 ± 11.9 | 94.1 ± 11.8 | <0.001 |
| Hypertension grades | ||||
| 1 or controlled blood pressure ⁎ | 937 (30.0%) | 376 (30.4%) | 561 (29.7%) | 0.411 |
| 2 | 1,230 (39.3%) | 497 (40.2%) | 733 (38.7%) | |
| 3 | 961 (30.7%) | 363 (29.4%) | 598 (31.6%) | |
| Ankle–brachial index | 1.03 ± 0.09 | 1.05 ± 0.10 | 1.02 ± 0.09 | <0.001 |
| Body mass index (kg/m 2 ) | 25.6 ± 3.6 | 24.9 ± 3.3 | 26.1 ± 3.6 | <0.001 |
| Waist circumference (cm) | 85.7 ± 9.7 | 85.9 ± 9.9 | 85.5 ± 9.6 | 0.266 |
| Current smoker | 716 (22.9%) | 646 (52.3%) | 70 (3.7%) | <0.001 |
| Current alcoholic drinker | 711 (22.7%) | 665 (53.8%) | 46 (2.4%) | <0.001 |
| Antihypertensive treatment | 1,465 (46.8%) | 541 (43.8%) | 924 (48.8%) | 0.005 |
| Heart rate (beats/min) | ||||
| <70 | 1,170 (37.4%) | 529 (42.8%) | 641 (33.9%) | <0.001 |
| 70–80 | 1,218 (38.9%) | 459 (37.1%) | 759 (40.1%) | |
| ≥80 | 740 (23.7%) | 248 (20.1%) | 492 (26.0%) | |
| Counties | ||||
| Ganyu (coastal) | 1,065 (34.0%) | 460 (37.2%) | 605 (32.0%) | 0.002 |
| Donghai (inland) | 2,063 (66.0%) | 776 (62.8%) | 1,287 (68.0%) | |
| Living standards | ||||
| Poor | 374 (12.0%) | 119 (9.6%) | 255 (13.5%) | <0.001 |
| Medium | 2,402 (76.8%) | 947 (76.6%) | 1,455 (76.9%) | |
| Good | 352 (11.3%) | 170 (13.8%) | 182 (9.6%) | |
| Red meat consumption | ||||
| <1 time/week | 1,983 (63.4%) | 642 (51.9%) | 1,341 (70.9%) | <0.001 |
| 1–2 times/week | 826 (26.4%) | 402 (32.5%) | 424 (22.4%) | |
| ≥3 times/week | 319 (10.2%) | 192 (15.5%) | 127 (6.7%) | |
| Fruit and vegetable consumption | ||||
| <500 g/week | 37 (1.2%) | 20 (1.6%) | 17 (0.9%) | 0.084 |
| 500–1,500 g/week | 573 (18.3%) | 239 (19.3%) | 334 (17.7%) | |
| ≥1,500 g/week | 2,518 (80.5%) | 977 (79.0%) | 1,541 (81.4%) | |
| Sleeping quality | ||||
| Good | 1,222 (39.1%) | 632 (51.1%) | 590 (31.2%) | <0.001 |
| Medium | 1,307 (41.8%) | 438 (35.4%) | 869 (45.9%) | |
| Poor | 599 (19.1%) | 166 (13.4%) | 433 (22.9%) | |
| Education | ||||
| Illiterate | 2,000 (63.9%) | 442 (35.8%) | 1,558 (82.3%) | <0.001 |
| Primary level | 451 (14.4%) | 276 (22.3%) | 175 (9.2%) | |
| Elementary or higher levels | 677 (21.6%) | 518 (41.9%) | 159 (8.4%) | |
| Physical activity | ||||
| Low | 1,191 (38.1%) | 459 (37.1%) | 732 (38.7%) | 0.162 |
| Moderate | 1,220 (39.0%) | 507 (41.0%) | 713 (37.7%) | |
| High | 717 (22.9%) | 270 (21.8%) | 447 (23.6%) |
⁎ One hundred twenty-one subjects with antihypertensive treatment and controlled blood pressure were included.
Prevalence of LE-PAD was 9.0% (10.0% in women and 7.4% in men; Table 1 ). In the multivariable logistic regression model, older age, waist circumference ≥90 cm, grade 2 or 3 hypertension, increased heart rate at rest, poor sleep quality, women in the coastal area, and women with BMI ≥25 kg/m 2 were independent associated factors for LE-PAD ( Table 2 ).
| Variable | Total | Men | Women | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Prevalence | Adjusted OR (95% CI) | p Value | Prevalence | Adjusted OR (95% CI) | p Value | Prevalence | Adjusted OR (95% CI) | p Value | |
| Gender | |||||||||
| Men | 92 (7.4%) | 1.00 ‡ | |||||||
| Women | 190 (10.0%) | 1.20 (0.81–1.78) | 0.363 | ||||||
| Age (years) | |||||||||
| 45–55 | 71 (7.2%) | 1.00 ‡ | 19 (5.4%) | 1.00 ‡ | 52 (8.2%) | 1.00 ‡ | |||
| 55–65 | 116 (8.6%) | 1.21 (0.87–1.67) | 0.256 | 42 (8.1%) | 1.61 (0.88–2.95) | 0.120 | 74 (9.0%) | 1.06 (0.71–1.59) | 0.762 |
| 65–75 | 95 (12.0%) | 1.82 (1.27–2.61) | 0.001 | 31 (8.6%) | 1.72 (0.88–3.35) | 0.112 | 64 (14.8%) | 1.98 (1.27–3.09) | 0.003 |
| Body mass index (kg/m 2 ) | |||||||||
| <25 | 99 (6.9%) | 1.00 ‡ | 47 (7.0%) | 1.00 ‡ | 52 (6.8%) | 1.00 ‡ | |||
| ≥25 | 183 (10.8%) | 1.37 (0.99–1.88) | 0.055 | 45 (8.0%) | 1.03 (0.57–1.86) | 0.921 | 138 (12.2%) | 1.62 (1.09–2.41) | 0.016 |
| Waist circumference (cm) | |||||||||
| <90 | 152 (7.5%) | 1.00 ‡ | 53 (6.7%) | 1.00 ‡ | 99 (7.9%) | 1.00 ‡ | |||
| ≥90 | 130 (11.9%) | 1.48 (1.09–2.00) | 0.012 | 39 (8.8%) | 1.54 (0.85–2.79) | 0.154 | 91 (14.2%) | 1.56 (1.09–2.23) | 0.016 |
| Current smoker | 55 (7.7%) | 1.05 (0.71–1.56) | 0.798 | 50 (7.7%) | 1.18 (0.74–1.87) | 0.497 | 5 (7.1%) | 0.56 (0.21–1.48) | 0.246 |
| Current alcoholic drinker | 49 (6.9%) | 0.80 (0.53–1.22) | 0.308 | 47 (7.1%) | 0.91 (0.57–1.46) | 0.702 | 2 (4.3%) | 0.37 (0.09–1.59) | 0.180 |
| Antihypertensive treatment | |||||||||
| Untreated | 150 (9.0%) | 1.00 ‡ | 48 (6.9%) | 1.00 ‡ | 102 (10.5%) | 1.00 ‡ | |||
| Treated | 132 (9.0%) | 0.96 (0.74–1.24) | 0.760 | 44 (8.1%) | 1.18 (0.75–1.85) | 0.473 | 88 (9.5%) | 0.86 (0.63–1.18) | 0.342 |
| Hypertension grades | |||||||||
| 1 or controlled blood pressure † | 59 (6.3%) | 1.00 ‡ | 23 (6.1%) | 1.00 ‡ | 36 (6.4%) | 1.00 ‡ | |||
| 2 | 117 (9.5%) | 1.47 (1.05–2.04) | 0.023 | 29 (5.8%) | 0.96 (0.54–1.70) | 0.879 | 88 (12.0%) | 1.77 (1.17–2.68) | 0.007 |
| 3 | 106 (11.0%) | 1.62 (1.15–2.27) | 0.006 | 40 (11.0%) | 1.96 (1.13–3.40) | 0.016 | 66 (11.0%) | 1.47 (0.95–2.28) | 0.083 |
| Heart rate (beats/min) | |||||||||
| <70 | 81 (6.9%) | 1.00 ‡ | 34 (6.4%) | 1.00 ‡ | 47 (7.3%) | 1.00 ‡ | |||
| 70–80 | 114 (9.4%) | 1.35 (1.00–1.83) | 0.049 | 33 (7.2%) | 1.20 (0.72–1.99) | 0.486 | 81 (10.7%) | 1.44 (0.98–2.12) | 0.065 |
| ≥80 | 87 (11.8%) | 1.61 (1.16–2.23) | 0.004 | 25 (10.1%) | 1.54 (0.88–2.68) | 0.129 | 62 (12.6%) | 1.63 (1.08–2.45) | 0.020 |
| Counties | |||||||||
| Ganyu (coastal) | 109 (10.2%) | 1.00 ‡ | 33 (7.2%) | 1.00 ‡ | 76 (12.6%) | 1.00 ‡ | |||
| Donghai (inland) | 173 (8.4%) | 0.75 (0.57–0.98) | 0.037 | 59 (7.6%) | 1.07 (0.66–1.74) | 0.773 | 114 (8.9%) | 0.65 (0.47–0.90) | 0.010 |
| Living standards | |||||||||
| Poor | 33 (8.8%) | 1.00 ‡ | 12 (10.1%) | 1.00 ‡ | 21 (8.2%) | 1.00 ‡ | |||
| Medium | 218 (9.1%) | 1.11 (0.75–1.66) | 0.601 | 69 (7.3%) | 0.74 (0.38–1.47) | 0.393 | 149 (10.2%) | 1.28 (0.77–2.10) | 0.342 |
| Good | 31 (8.8%) | 1.01 (0.58–1.75) | 0.980 | 11 (6.5%) | 0.65 (0.26–1.68) | 0.377 | 20 (11.0%) | 1.14 (0.57–2.28) | 0.710 |
| Red meat consumption (times/week) | |||||||||
| <1 | 182 (9.2%) | 1.00 ‡ | 51 (7.9%) | 1.00 ‡ | 131 (9.8%) | 1.00 ‡ | |||
| 1–2 | 76 (9.2%) | 1.06 (0.79–1.43) | 0.692 | 30 (7.5%) | 1.01 (0.61–1.65) | 0.977 | 46 (10.8%) | 1.10 (0.76–1.60) | 0.620 |
| ≥3 | 24 (7.5%) | 0.82 (0.51–1.33) | 0.424 | 11 (5.7%) | 0.79 (0.38–1.64) | 0.529 | 13 (10.2%) | 0.93 (0.49–1.76) | 0.829 |
| Fruit and vegetable consumption (g/week) | |||||||||
| <500 | 4 (10.8%) | 1.00 ‡ | 1 (5.0%) | 1.00 ‡ | 3 (17.6%) | 1.00 ‡ | |||
| 500–1,500 | 52 (9.1%) | 0.80 (0.27–2.39) | 0.688 | 20 (8.4%) | 2.26 (0.27–18.78) | 0.450 | 32 (9.6%) | 0.39 (0.10–1.49) | 0.166 |
| ≥1,500 | 226 (9.0%) | 0.87 (0.30–2.53) | 0.795 | 71 (7.3%) | 1.81 (0.23–14.53) | 0.577 | 155 (10.1%) | 0.51 (0.14–1.91) | 0.319 |
| Sleeping quality | |||||||||
| Good | 102 (8.3%) | 1.00 ‡ | 48 (7.6%) | 1.00 ‡ | 54 (9.2%) | 1.00 ‡ | |||
| Medium | 111 (8.5%) | 0.96 (0.72–1.29) | 0.795 | 25 (5.7%) | 0.76 (0.45–1.26) | 0.280 | 86 (9.9%) | 1.11 (0.77–1.60) | 0.588 |
| Poor | 69 (11.5%) | 1.41 (1.00–1.97) | 0.047 | 19 (11.4%) | 1.69 (0.94–3.03) | 0.081 | 50 (11.5%) | 1.45 (0.95–2.21) | 0.082 |
| Education | |||||||||
| Illiterate | 193 (9.7%) | 1.00 ‡ | 36 (8.1%) | 1.00 ‡ | 157 (10.1%) | 1.00 ‡ | |||
| Primary level | 36 (8.0%) | 0.94 (0.64–1.40) | 0.778 | 20 (7.2%) | 0.90 (0.50–1.61) | 0.719 | 16 (9.1%) | 0.92 (0.53–1.61) | 0.782 |
| Elementary or higher levels | 53 (7.8%) | 1.08 (0.73–1.59) | 0.701 | 36 (6.9%) | 1.09 (0.63–1.87) | 0.765 | 17 (10.7%) | 1.19 (0.67–2.12) | 0.560 |
| Physical activity | |||||||||
| Low | 124 (10.4%) | 1.00 ‡ | 34 (7.4%) | 1.00 ‡ | 90 (12.3%) | 1.00 ‡ | |||
| Moderate | 98 (8.0%) | 0.86 (0.64–1.16) | 0.323 | 34 (6.7%) | 0.92 (0.54–1.55) | 0.747 | 64 (9.0%) | 0.83 (0.58–1.19) | 0.308 |
| High | 60 (8.4%) | 0.95 (0.67–1.35) | 0.781 | 24 (8.9%) | 1.33 (0.74–2.41) | 0.343 | 36 (8.1%) | 0.79 (0.51–1.23) | 0.298 |
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