LIANG Kai, WANG Chuan, YAN Fei, YANG Jun Peng, TIAN Meng,WANG Ling Shu, HOU Xin Guo, and CHEN Li

Department of Endocrinology, Qilu Hospital of Shandong University, Institute of Endocrinology and Metabolism Disease, Shandong University, Key Laboratory of Endocrinology and Metabolism Disease, Shandong Province Medicine &Health, Jinan 250012, Shandong, China

In 2017, American College of Cardiology(ACC)/American Heart Association (AHA) et al. jointly released the latest guidelines for adult hypertension,exactly including prevention, diagnosis, assess and treatment, in which blood pressure levels greater than 130/80 mmHg were defined as hypertension[1].Based on these modified guidelines, the morbidity of hypertension in US increased from 32% to 46%. In addition, the latest guidelines cancelled the previous definition of prehypertension (120−129/80−89 mmHg) and redefined that blood pressure levels 120−129/＜ 80 mmHg as elevated blood pressure,130−139/80−89 mmHg as stage 1 hypertension,and ＞ 140/90 mmHg as stage 2 hypertension. The 2017 ACC/AHA Hypertension Guidelines emphasized the importance of early intervention to prevent the development of cardiovascular and cerebrovascular diseases. However, the new definition of adult hypertension posed a new challenge for the prevention and treatment of hypertension, which include patient’s mentality, government public policy-making, health economy, and health education. Moreover, there is a need to prove that it is proper to popularize this new definition of hypertension in other countries. Unlike the 2017 ACC/AHA guidelines, the 2018 ESC-ESH guidelines for the management of arterial hypertension still adhere to the use of more than 140/90 mmHg as the standard for hypertension[2]. The revision of the Chinese guidelines for the prevention and treatment of hypertension in 2018 also does not adopt the new American hypertension standards.

In China, about 32.5% of Chinese adults are hypertensive, which is similar to the prevalence in the United States[3]. Based on the 2017 ACC/AHA guidelines, the morbidity of hypertension in the Chinese population has significantly increased.However, no study assessing whether the new American hypertension standards fit the Chinese setting has been conducted to date. Thus, we conducted an epidemiological investigation on middle-aged and elderly residents of community in 2012 and compared the differences in cardiovascular risk factors between stage 1 hypertension and elevated blood pressure on the basis of the 2017 ACC/AHA guidelines to discuss the feasibility of the new hypertension standards for Chinese adults.

This study randomly recruited 10,028 subjects(40 years of age and older) from Shandong Province from January to April 2012, which was one part of the baseline survey of the reaction study[4,5]. The following exclusion criteria were implemented:(1) previously diagnosed hypertension; (2) systolic pressure ≤ 90 mmHg or diastolic pressure ≤60 mmHg; (3) previously diagnosed kidney disease,including autoimmune or drug-induced kidney disease, nephritis, renal fibrosis or renal failure;(4) previously diagnosed hepatic disease, including fatty liver, liver cirrhosis and autoimmune hepatitis;and (5) any malignant disease. Ultimately, 6,863 subjects (4,581 women) were eligible for analysis.The institutional review board at Department of Endocrinology and Metabolic Disease, Ruijin Hospital, Shanghai Jiaotong University School of Medicine approved the study protocol. All the subjects provided their informed consent. Trained interviewers conducted in-person surveys when the participants attended a health examination at community health care settings. After at least 10 h of overnight fasting, venous blood samples were collected for measurements of fasting blood glucose(FBG), triglyceride (TG), total cholesterol (TC), highdensity lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and creatinine. Twohour plasma glucose (2-h PG) levels were measured after subjects had completed a 75-g oral glucose tolerance test (OGTT). Hemoglobin A1c (HbA1c) was measured via high-performance liquid chromatography (VARIANT II and D-10 Systems, BIORAD, USA). Metabolic abnormalities were defined according to the standard of care for type 2 diabetes in China. Chronic kidney disease (CKD) was defined as eGFR ＜ 60 mL/(min·1.73 m2), which was calculated from the creatinine levels using the CKDEPI formula.

All of the data were analyzed using SPSS 16.0(SPSS Inc., Chicago, IL, USA). Continuous variables displaying a normal distribution were expressed as the means ± SD, and variables displaying a nonnormal distribution were presented as medians(interquartile range). Categorical variables were presented as percentages (%). Differences among groups were detected via one-way ANOVA (LSD)(continuous variables displaying a normal distribution), the Kruskal-Wallis H test (skewed continuous variables), or the chi-square test(categorical variables). The association between BP and metabolic abnormalities were analyzed using multiple logistic regression. Differences displaying P＜ 0.05 were considered statistically significant.

As shown in Table 1, the respective percentages of stage 1 hypertension and stage 2 hypertension were 28.0% and 52.9% in males, and 27.7% and 43.0% in females. Only 8.2% of the males and 15.3%of the females showed normal BP. Table 2 showed that the stage 1 hypertension group had a higher proportion of abdominal obesity, hyperglycemia,high TG, high TC, and high LDL-C compared to the elevated BP group. Furthermore, the stage 2 hypertension group showed the most remarkable metabolic abnormality. There was no significant difference between the normal and elevated groups in metabolic abnormality after adjusting for age and gender. However, the stage 1 hypertension group showed an increase in OR s for abdominal obesity(OR = 1.274, P = 0.004), hyperglycemia (OR = 1.246,P = 0.015), and elevated TG (OR = 1.261, P = 0.014),TC (OR = 1.256, P = 0.006), and LDL-C (OR = 1.235,P = 0.018) levels compared to the elevated BP group even after adjusting for age and gender. As expected, the stage 2 hypertension groups also presented significantly higher OR s for abdominal obesity (OR = 1.959, P ＜ 0.001), hyperglycemia (OR =1.758, P ＜ 0.001), and elevated TG (OR = 1.832, P ＜0.001), TC (OR = 1.421, P ＜ 0.001), and LDL-C (OR =1.525, P ＜ 0.001) levels compared to the elevated BP group after adjusting for age and gender. In addition,the risks of low HDL-C and CKD did not differ among the four groups (Table 3).

Our study would provide new evidence on the new hypertension standard of the 2017 ACC/AHA guidelines in the application of community residentsin China. The China Kadoorie Biobank Study[3]revealed that about 32.5% of Chinese adults had hypertension, which was defined as SBP ≥ 140 mmHg or DBP ≥ 90 mmHg. Undoubtedly, the new standards of hypertension were bound to significantly increase the prevalence of hypertension. A study[6]comparing the hypertension profiles of China and the United States showed that hypertension was more common in the United States, but blood pressure levels were higher in China, which may be responsible for the observed high stroke prevalence in Chinese adults.Meanwhile, the levels of treatment and control in hypertension were significantly lower in China, and clustering of hypertension with other cardiovascular risk factors was more common in China. Therefore,early intervention may be helpful in changing this situation.

Table 1. Distribution of BP in study participants, n (%)

The adoption of the 2017 ACC/AHA hypertension guidelines will markedly increase the number of people with hypertension and thus requiring treatment, which was based on evidencebased evidence of cardiovascular risk reduction but had also faced controversy. Patients marked with stage 1 hypertension may have adverse psychological effects, and not every patient diagnosed with stage 1 hypertension benefits fromtreatment. Moreover, whether stage 1 hypertension is related to cardiovascular disease or even cardiovascular mortality requires further investigation, particularly in the Chinese population. To this end, we have explored the differences in cardiovascular risk factors between stage 1 hypertension and elevated BP, which were considered as the same group in the past guide,including obesity, hyperglycemia, dyslipidemia, and CKD. We found that the detection rate of abdominal obesity, hyperglycemia, and dyslipidemia among adults with stage 1 hypertension significantly increased compared to the elevated BP group. In this perspective, the new version of the American guidelines for hypertension seems to be supported in the Chinese population.

Table 2. Characteristics of the study participants based on BP

Cardiovascular disease risks are the main basis for the determination of antihypertensive treatment strategies. A large number of studies have reported a gradient of progressively higher CVD risk going from normal BP to elevated BP and stage 1 hypertension, however, this does not mean that all stage 1 hypertension should be treated with antihypertensive drugs[7]. SPRINT studies have shown that SBP could only benefit when the SBP is reduced to approximately 130 mmHg, but the majority of hypertensive patients included in this study had an SBP ≥ 140 mmHg[8]. A subgroup analysis of the HOPE-3 study showed that patients with SBP ＞ 143.5 mmHg benefited from antihypertensive therapy[9]. A meta-analysis showed that antihypertensive treatment was not associated with mortality and major cardiovascular events but might offer additional protection in patients with CHD if baseline SBP is below 140 mmHg[10]. Therefore, in the new guidelines, stage 1 hypertension should be coupled with individualized treatment plans.

This study was a cross-sectional observationalstudy that validates the feasibility of the 2017 ACC/AHA hypertension guidelines in the Chinese population in the context of the association of hypertension with other metabolic diseases.However, there is still a lack of prospective follow-up studies to determine whether the Chinese population should accept this more stringent diagnostic and therapeutic criteria for hypertension.

Table 3. Multiple logistic regression analysis of the association between BP and metabolic abnormality

#Correspondence should be addressed to CHEN Li,Tel/Fax: 86-531-82169323, E-mail: chenli3@medmail.com.cn; HOU Xin Guo, Tel/Fax: 86-531-82169323, E-mail:houxinguo@medmail.com.cn

Biographical note of the first author: LIANG Kai, male,born in 1986, Master of Medicine, majoring in clinical epidemiology of diabetes and endocrinology.

Received: August 10, 2019;Accepted: December 3, 2019