Cardiovascular disease is a major public health problem

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1 Original Article Prevalence, Awareness, Treatment, and Control of Hypertension Among Residents in Guangdong Province, China, 2004 to 2007 Bayi Xu, MS; Zhixia Xu, MS; Xiaojun Xu, MS; Qiumao Cai, MS; Yanjun Xu, BS Background As a result of the large variation in geographic, demographic, and socioeconomic characteristics in different regions of China, the prevalence and treatment of hypertension in different regions differ widely. However, little is known about the recent trends of hypertension in Guangdong Province in southern China. We assessed the trends in prevalence, awareness, treatment, and control of hypertension in Guangdong Province between 2004 and Methods and Results The Guangdong Provincial Chronic Disease Risk Factor Surveillance, modeled on the national Chronic Disease Risk Factor Surveillance, was conducted every 3 years beginning in 2004 with a representative sample of Guangdong Province residents 18 years of age. Data from the Guangdong Provincial Chronic Disease Risk Factor Surveillance I (2004; n=7633) and II (2007; n=6447) were used to describe the trends in the prevalence of hypertension among Guangdong Province adults. Hypertension outcomes were examined with interview and examination data. From 2004 to 2007, the age-standardized prevalence rate of hypertension in Guangdong Province residents increased from 12.2% to 15.4% (P<0.001), with the largest increases among rural women (from 9.3% to 19.1%; P<0.001). Among hypertensive people, there was no improvement in awareness and treatment between 2004 and 2007; the control rates decreased from 7.1% in 2004 to 4.5% in 2007 (P<0.01). Conclusions One in 7 Guangdong Province adults is hypertensive, but only one quarter are aware of the condition. About 22% of hypertensive patients receive treatment, and few have their hypertension effectively controlled. Hypertension has become a major public health problem in southern China. Comprehensive public health measures need to be taken to decrease the incidence of hypertension and to prevent the progression of hypertension to cardiovascular disease. (Circ Cardiovasc Qual Outcomes. 2013;6: ) Key Words: hypertension prevalence prevention surveillance trends Cardiovascular disease is a major public health problem and a leading cause of death and disability in most developed and some developing countries. 1,2 Hypertension is one of the most important and modifiable risk factors of cardiovascular diseases. 3 One quarter of the world s adult population has hypertension, and this is likely to increase to 29% by National survey data demonstrate that the prevalence of hypertension in the Chinese adult population has quadrupled from 5% in 1958 to nearly 19% in ,6 About 153 million Chinese adults were hypertensive in Modeled projections indicate an increase to 284 to 314 million hypertensive patients by 2025 in China. 8 Compounding this high burden of hypertension is a lack of awareness and insufficient treatment in those with hypertension. The China National Nutrition and Health Survey (2002) suggested that only one quarter of the hypertensive patients are aware of their condition and that few have their hypertension effectively controlled. 9 However, because of the large variation in geographic, demographic, and socioeconomic characteristics in different regions of China, the prevalence and rates of hypertension awareness, treatment, and control in different regions may differ widely. 10 Guangdong Province is on the South Sea coast of China. During the past decades, it has seen the largest human migration in and the rapid urbanization of China and has become the most populous province since 2005, registering 104 million residents (including permanent residents and migrants who lived in the province for at least 6 months of the year) in 2010 and accounting for 7.79% of the country s population. 11 As a rapidly developing coastal province, Guangdong Province is currently experiencing rapid economic, social, and cultural changes, including an accelerated pace of nutrition and lifestyle transition that may result in a greatly increased burden of chronic diseases such as hypertension. 12 To plan rationally for the use of limited healthcare resources, provincial surveys are necessary to provide updated health information for the development of effective programs and strategies to prevent and control hypertension. However, little is known about the recent Received July 14, 2012; accepted January 25, From the Department of Noncommunicable Disease Control and Prevention, Center for Disease Control and Prevention of Shantou Municipal, Guangdong Province, China (B.X., Z.X.), and Department of Noncommunicable Disease Control and Prevention, Center for Disease Control and Prevention of Guangdong Province, China (X.X., Q.C., Y.X.). The online-only Data Supplement is available at Correspondence to Yanjun Xu, Department of Noncommunicable Disease Control and Prevention, Center for Disease Control and Prevention of Guangdong Province, 176, Xin Gang Xi Rd, Guangzhou, , China. gdxyj05@21cn.com 2013 American Heart Association, Inc. Circ Cardiovasc Qual Outcomes is available at DOI: /CIRCOUTCOMES

2 218 Circ Cardiovasc Qual Outcomes March 2013 WHAT IS KNOWN The prevalence of hypertension in China has increased substantially in the past decades. There is marked regional variation in demographic and socioeconomic characteristics in China; little is known about the trends in hypertension in specific Chinese provinces. WHAT THE STUDY ADDS The prevalence of hypertension in Guangdong Province in southern China is increasing in general (from an age-standardized prevalence of 12.2% in 2004 to 15.4% in 2007); this increase is most pronounced among rural women. Awareness and treatment of hypertension were generally low and did not improve between 2004 and The proportion of patients with controlled hypertension declined. Hypertension is a public health issue of increasing importance in Guangdong Province. trends in the prevalence and rates of hypertension awareness, treatment, and control in Guangdong Province. In this study, data from the Guangdong Provincial Chronic Disease Risk Factor Surveillance (GPCDRFS), a continuous (carried out every 3 years) representative cross-sectional chronic disease risk factor surveillance in Guangdong Province, were used to describe the trends in the prevalence and rates of hypertension awareness, treatment, and control among Guangdong Province adults from 2004 to Methods Data from the GPCDRFS are used to assess the health-related risk factors of the civilian Guangdong Province. The field survey of GPCDRFS was carried out on the basis of part of the China National Disease Surveillance Points system, which has been shown to be representative of the whole population. Detailed descriptions of the system were published elsewhere. 13 Multistage cluster sampling was used to select a representative sample of residents 18 to 69 years of age living in sample areas (the Figure in the online-only Data Supplement). With the use of proportional probability sampling method, 2 townships (in rural areas) or streets (urban areas) were selected from each disease surveillance point site; in addition 2 administrative villages/communities were selected from each sampled township/street, and 1 village neighborhood/community neighborhood was selected from each village/community by simple random sampling. In every selected village/community neighborhood, at least 90 households were selected by simple random sampling, and 1 subject was determined by the Kish grid method from the selected household. Only people who had lived in their current residence for 6 months or longer in the past 12 months were eligible to participate. A replacement method, which required the substitute to have a household structure similar to that of the sampled family, was adopted in the survey when interviewers could not reach the sampled family after 3 attempts to guarantee adequate sample size. Informed consent was obtained from all participants, and the protocol was approved by the National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention. All recruited residents were invited to participate in the survey at a convenient and accessible site or at home. A standardized questionnaire was administered by trained interviewers during a face-to-face individual interview. Data collected in the questionnaire included demographic information and lifestyle factors related to chronic diseases such as smoking, alcohol consumption, physical activity, diet, and personal and family medical history. Physical measurements were also taken on all subjects, including height, weight, waistline, and blood pressure (BP). All participants had their BP measured with standardized mercury sphygmomanometers that were purchased centrally. Investigators were trained in the measurement of BP and in the questionnaire before the survey. Two consecutive readings of BP were taken on the right arm according to 1999 World Health Organization/International Society of Hypertension guidelines on hypertension 14 with the participant in a seated position after 5 minutes of rest; the mean of the 2 measures was used for analysis. Respondents who were pregnant or for whom no BP data were available were excluded from the analysis. The final analytic sample consisted of 7633 respondents for GPCDRFS I and 6447 respondents for GPCDRFS II, all 18 years of age. Hypertension was defined according to the Chinese Guidelines on Prevention and Control of Hypertension 15 and the Sixth Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines 16 as systolic BP (SBP) 140 mm Hg, diastolic BP (DBP) 90 mm Hg, and self-reported treatment of hypertension with antihypertensive medication in the last 2 weeks. Awareness was defined as hypertensive respondents having been told at least once by a health professional that they had hypertension. Hypertensive adults were included in the treatment category if they reported the use of a prescribed medicine for hypertension during the previous 2 weeks. Among hypertensive people, control was defined as an SBP <140 mm Hg and a DBP <90 mm Hg. Body mass index (BMI) was defined as measured weight in kilograms divided by height in meters squared. There were 3 BMI categories: underweight/normal, defined as a BMI <24 kg/m 2 ; overweight, defined as 24 kg/m 2 BMI<28 kg/m 2 ; and obese, defined as a BMI 28 kg/m 2. 17,18 All questionnaires were doubly entered using Epidata 3.0 to reduce entry errors. SPSS 17.0 for Windows (Chicago, IL) was used for data management and statistical analysis. Age standardization was done with the Guangdong 2000 Census population used as the standard population. The process was as follows. First, we calculated the hypertension prevalence in all age groups (18 29, 30 39, 40 49, 50 59, and years of age) in the sample. Second, we found a standard population (the Guangdong 2000 Census population). Third, we calculated the constituent ratio of all age groups (like the first step) in the standard population. Fourth, we multiplied the prevalence (from the first step) by the constituent ratio (from the third step) of all age groups. Fifth, we summed up the product (from the fourth step) of all age groups, and the sum was the standardized rate. Comparisons of the differences in means and percentages between the 2 surveys were performed by use of t tests or χ 2 tests. Two-tailed values of P<0.05 were considered statistically significant. Results In this analysis, data on individuals (7633 in 2004, 6447 in 2007) were included. Table 1 shows the age, sex, geographic distribution, weight, waistline, BMI, and BP of the Guangdong Province population estimated from GPCDRFS 2004 to There was no overall significant difference in the mean age, weight, and geographic distribution between 2004 and However, the age group and sex distributions were different between 2004 and Compared with 2004, BMI and waistline measurements in 2007 had increased significantly (P<0.01). With the increasing BMI and waistline measurements, the mean SBPs and DBPs increased (P<0.01) in all age groups from 2004 to 2007 (Table I in the online-only Data Supplement). From 2004 to 2007, the age-standardized prevalence rate of hypertension increased from 12.2% to 15.4% (P<0.001), with a 30% relative increase (Table 2). Further stratified analysis

3 Xu et al Hypertension Among Residents in Guangdong Province 219 Table 1. Phases Characteristics of Participants in the 2 GPCDRFS Characteristics 2004 (n=7633) 2007 (n=6447) P Age, mean (SE), y (0.14) (0.16) NS Age group, % y 12.5 (1.1) 13.0 (1.2) < y 27.3 (1.0) 22.2 (1.1) y 29.4 (1.0) 26.3 (1.1) y 19.0 (1.0) 23.5 (1.1) y 11.8 (1.1) 15.1 (1.2) Women, % 56.4 (0.7) 52.2 (0.9) <0.01 Distribution, % Rural 59.3 (0.7) 57.7 (0.8) NS City 40.7 (0.9) 42.3 (1.0) Weight, mean (SE), kg (0.27) (0.12) NS Waist circumference, (0.16) (0.12) <0.01 mean (SE), cm BMI, mean (SE), kg/m (0.04) (0.04) <0.01 BP, mean (SE), mm Hg Systolic (0.21) (0.24) <0.01 Diastolic (0.13) (0.14) <0.01 BMI indicates body mass index; BP, blood pressure; GPCDRFS, Guangdong Provincial Chronic Disease Risk Factor Surveillance; and NS, not statistically significant (P>0.05). Data are weighted to the Guangdong Province population (2000) and expressed as percentages unless otherwise noted. according to sex and geographic distribution showed that the increases were greater for rural men and women, especially for women, and that the changes in city men and women were not statistically significant. Age-specific prevalence rates increased significantly in rural women 30 to 69 years of age and rural men 40 to 49 years of age but decreased significantly in city men 40 to 49 years of age. Age-specific prevalence rates did not change significantly in city women (Table II in the online-only Data Supplement). Table 3 presents time trends in the BP distributions in the untreated Guangdong Province population. The category of BP status was set by the Seventh Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The most notable change seen in most geographic sex groups was the upward shift in BP values, lowering the percentage in the normal group and increasing the percentage in the prehypertension or hypertension group (Table III in the online-only Data Supplement). This distribution change also occurred in the 3 BMI categories. With the elevation of BMI level, the prevalence of hypertension increased. Table 4 indicates that overall there was no improvement in the awareness of hypertension from 2004 to Treatment rates tended to improve only in city men 50 to 69 years of age. The control rates did not improve, but worsened overall, especially in rural and city women 50 to 69 years of age (Table IV in the online-only Data Supplement). Table 5 presents the net results of the changes in terms of mean BP levels. Age-standardized mean SBP increased by 4 mm Hg overall and by 3 and 5 mm Hg for men and women, respectively. SBP increased only in nonhypertensive population, whereas age-standardized mean DBPs increased in both the nonhypertensive and hypertensive (treated and untreated) population by 1 to 5 mm Hg, except female treated hypertensive patients. Discussion To the best of our knowledge, our study is the first to report temporal changes in the prevalence of hypertension and the rates of hypertension awareness, treatment, and control in south China. The major observations of this study are that in Guangdong Province (1) age-standardized hypertension prevalence rates are increasing in general, especially in rural women, and the prevalence rate of hypertension increased by 110%; (2) consistent with other research, 19 the increase in the prevalence of hypertension can be partly attributed to increasing overweight/obesity, including abdominal obesity; (3) among untreated people, there is a decrease in the proportion with normal BP and an increase in the prehypertension category; and (4) awareness and treatment rates remained disproportionately and unacceptably low and did not improve in general, whereas control rates declined and are still far from satisfactory. Guangdong Province was originally part of a low-incidence area of hypertension; the standardized prevalence rate was 4.7% in However, with economic development, changes in lifestyle and diet, and an increase in life expectancy, the prevalence of hypertension in Guangdong Province has increased and will continue to increase dramatically. Compared with 1979, the prevalence rate of hypertension in 2002 increased 149% and reached 11.7%, 21 with the increase rate exceeding the national rate of the same period. The result of our research indicated that, from 2004 to 2007, the age-standardized prevalence rate of hypertension increased from 12.2% to 15.4%, a Table 2. Age-Standardized Prevalence of Hypertension in the Guangdong Province Adult Population: 2004 and 2007 Population Group n % (SE) n % (SE) All total (0.4) (0.4) < Men (0.6) (0.7) NS 1.1 Women (0.5) (0.6) < Rural (0.5) (0.6) < City (0.6) (0.6) NS 0.9 NS indicates not statistically significant, P>0.05. *Ratio, rate of hypertension in 2007 divided by that in P Value Ratio*

4 220 Circ Cardiovasc Qual Outcomes March 2013 Table 3. Distribution of BP Categories in Untreated Guangdong Province Adult Population, 2004 and 2007 Survey Period Normal, % Prehypertension, % Stage 1, % Stage 2, % P * Population group All total < Men < Women < Rural < City < Total population BMI <24 kg/m < BMI <0.001 kg/m BMI 29 kg/m < BMI indicates body mass index; and BP, blood pressure. A systolic BP of <120 mm Hg and a diastolic BP of <80 mm Hg is defined as normal BP. The successively higher categories are classified as determined by the higher category for systolic BP or diastolic BP. Prehypertension: systolic BP of 120 to 139 mm Hg or diastolic BP of 80 to 89 mm Hg; stage 1: systolic BP of 140 to 159 mm Hg or diastolic BP of 90 to 99 mm Hg; stage 2: systolic BP 160 mm Hg or diastolic BP 100 mm Hg. *The P value is a test of the difference in the distribution of BP categories between surveys in 2004 and % increase in 3 years. More alarmingly, this trend was much greater in rural women, from 9.3% to 19.1%. In 2003, the Seventh Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure introduced a new category of BP status between normotension and hypertension called prehypertension defined as an SBP of 120 to 139 mm Hg or DBP of 80 to 89 mm Hg in adults 18 years of age or older. 22 This category was suggested because of evidence indicating that overall cardiovascular risk and end-organ damage were already elevated in individuals with prehypertension of age compared with those with a BP <120/80 mm Hg. 23 In the Chinese population, prehypertension has been found to be associated with increased risk of hypertension and major cardiovascular diseases. 24,25 From 2004 to 2007, there were a decrease in the proportion with normal BPs and an increase in the prehypertension category among Guangdong Province adults. Clearly, urgent attention should be paid to preventing prehypertension, which frequently progresses to actual clinical hypertension over several years. 26 As in other economically developing countries, many clinicians in China lack public health service consciousness. Although national guidelines require BP to be measured during all outpatient visits, it is still very common that no BP checkup is performed, especially in rural China. In addition, community-based BP screening and education programs are uncommon in China. Muntner et al 27 found that a high proportion of the Chinese population with hypertension, 32.5%, had not had their BP measured within the preceding 5 years. This may partially explain the substantially lower rates of hypertension awareness in Guangdong Province. Our results indicate that hypertension was undertreated in Guangdong Province. Only one fifth of the participants with hypertension were receiving pharmacological treatment. This is substantially lower than the corresponding percentage (>60%) of the US population between 2003 and In addition, from 2004 to 2007, this trend did not improve. Furthermore, treated SBP levels were higher than untreated Table 4. Hypertension Awareness, Treatment, and Control in the Guangdong Province Adult Hypertensive Population, 2004 and 2007 Awareness, % Treatment, % Control, % Population Group P P P All total NS NS <0.01 Men NS NS NS Women NS NS <0.001 Rural NS NS NS City NS NS NS NS indicates not statistically significant, P>0.05.

5 Xu et al Hypertension Among Residents in Guangdong Province 221 Table 5. Age-Standardized Mean Systolic and Diastolic BPs for the Total Adult Population and Nonhypertensive, Treated Hypertensive, and Untreated Hypertensive Populations Systolic BP, mean (SE), mm Hg Diastolic BP, mean (SE), mm Hg Population Group P P All total 122 (0.2) 126 (0.2) < (0.1) 79 (0.1) <0.01 Nonhypertensive 116 (0.1) 119 (0.1) < (0.1) 75 (0.1) <0.01 Treated hypertensive 152 (1.3) 152 (1.4) NS 89 (0.7) 92 (0.7) <0.01 Untreated hypertensive 147 (0.5) 146 (0.6) NS 89 (0.5) 91 (0.3) <0.01 Men 124 (0.3) 127 (0.3) < (0.2) 80 (0.2) <0.01 Nonhypertensive 118 (0.2) 121 (0.2) < (0.2) 76 (0.1) <0.01 Treated hypertensive 153 (2.2) 152 (2.3) NS 90 (1.2) 95 (1.3) <0.05 Untreated hypertensive 146 (0.7) 145 (0.9) NS 90 (0.8) 92 (0.4) <0.05 Women 120 (0.3) 125 (0.4) < (0.2) 79 (0.2) <0.01 Nonhypertensive 114 (0.2) 117 (0.2) < (0.1) 74 (0.1) <0.01 Treated hypertensive 151 (1.6) 152 (1.9) NS 88 (0.9) 91 (0.8) NS Untreated hypertensive 147 (0.7) 148 (0.9) NS 88 (0.5) 91 (0.4) <0.01 BP indicates blood pressure; and NS, not statistically significant, P>0.05. hypertensives, and DBP levels were similar among treated and untreated hypertensives. This may be the result of the restriction of the use of BP-lowering medication to the most severe hypertensives. Of course, the antihypertensive effect of the use of BP-lowering medication to the most severe hypertensives is not great. Current Chinese guidelines for the management of hypertension 15 stipulate a BP treatment goal of 140/90 mm Hg, but only a small proportion of affected individuals in Guangdong Province receive adequate treatment or achieve effective BP control, consistent with previous studies conducted in China, including the 1991 National Survey, 29 the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA, ), 30 and the more recent survey of Liaoning Province (2006). 31 Two main limitations of the present study should be noted. First, BP was measured 2 times following a standard protocol during only a single visit. According to both World Health Organization and National Institutes of Health guidelines, hypertension should be defined on the basis of the average of at least 2 BP readings taken at 2 or more visits after an initial screening. 14,16 Second, the study was confined to adults 18 to 69 years old. In conclusion, our study indicated that Guangdong Province was undergoing an enormous increase in the prevalence of hypertension in the period 2004 to It also indicated that there were no improvements in the awareness, treatment, and control rates of hypertension. These findings suggest that public health measures and clinical practice during this period were ineffective at both reducing the prevalence and increasing the control of hypertension in the Guangdong Province population. They also suggest that hypertension has become a major public health problem in southern China and highlight the urgent need to develop strategies for the prevention and treatment of hypertension. In the future, we will explore the influencing factors that caused the rapid increase in hypertension in Guangdong Province and guide allocation of public resources to prevent hypertension. Acknowledgments This survey was supported by the Department of Health of Guangdong Province. We would like to thank all investigators from the municipal- and county-level Center for Disease Control and all who participated in the survey. None. Disclosures References 1. Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJ. Global and regional burden of disease and risk factors, 2001: systematic analysis of population health data. Lancet. 2006;367: He J, Gu D, Wu X, Reynolds K, Duan X, Yao C, Wang J, Chen CS, Chen J, Wildman RP, Klag MJ, Whelton PK. Major causes of death among men and women in China. 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