Cardiovascular risk stratification in Chinese patients with hypertension

The fundamental goal of management of hypertension is to reduce the incidence of cardiovascular, cerebrovascular, kidney, and vascular diseases events that have not occurred yet but will occur in the future. High blood pressure and elevated degree of blood pressure (grading) are the main risk factors for cardiovascular risk, but not the only determining factor. Cardiovascular risk also depends on the stage of the disease (target organ damage and comorbidities) and other strong and independent cardiovascular risk factors. Therefore, it becomes inevitable and reasonable to initiate antihypertensive drug therapy and recommend the blood pressure target and initiating combination therapy pathway based on the strategies that combine blood pressure levels with cardiovascular risk, and assessment of patient's condition according to the stratification of cardiovascular risk.

Evidence from clinical studies of antihypertensive therapy for 50 years shows that long‐term control of blood pressure levels in hypertensive patients below 140/90 mm Hg can achieve therapeutic benefits and significantly reduction of cardiovascular risk. However, after deep analysis of the factors affecting the size of the benefit, the cardiovascular risk level at baseline and the blood pressure reduction under antihypertensive therapy become the main determinants of the size of the benefit. The higher the cardiovascular risk or the greater the blood pressure reduction, the greater the benefit to quite a certain extent. Systematic review and meta‐analysis have demonstrated that patients with high cardiovascular risk or above could achieve more therapeutic benefits when blood pressure below 130/80 mm Hg than below 140/90 mm Hg, which is the evidence of the intensive blood pressure control of less than 130/80 mm Hg. However, from another perspective, the negative effects of intensive antihypertensive therapy and the harm effect of lower blood pressure target must be considered, that means the benefit/harm ratio. In patients at low or moderate cardiovascular risk, although the intensive antihypertensive therapy can reduce the relative risk (rate of incidents), the reduction of absolute risk (number of incidents) is very small. On the other hand, some patients at high risk or above may not be able to tolerate the intensive therapy and achieve long‐term adherence to treatment. To emphasis on the intensive blood pressure control, targets of below 130/80 mm Hg in all hypertensive patients will inevitably increase the number and proportion of so‐called refractory hypertension. From the perspective of weighing benefits and harm of treatment, it is obviously unreasonable to set a same target value of blood pressure control for all hypertensive patients across the board. Therefore, the 2018 Chinese Guidelines establish a dual‐target value for blood pressure control in hypertensive patients, with a basic and primary goal of below 140/90 mm Hg and a supplement and intensive goal of below 130/80 mm Hg in hypertensive patients with high‐risk and very high‐risk stratification.1

The primary goal of cardiovascular risk stratification is to identify patients at high cardiovascular risk. The 2018 Chinese Guidelines still recommend assessment of the cardiovascular risk using tabulating method and have been promoted and implemented in Chinese hypertensive population for more than a decade, including blood pressure level grading, number of significant risk factors, target organ damage, comorbidities of diabetes, chronic kidney disease, and clinical cardiovascular and cerebrovascular diseases. Patients with diabetes or chronic kidney disease are classified as at very high risk or high risk depending on whether there is a complication. The cardiovascular risk of hypertension in the 2018 Chinese Guidelines refers to composite risks of all the heart, brain, kidney, and vascular events associated with hypertension, rather than just atherosclerotic cardiovascular disease (ASCVD) events. ASCVD does not include events directly related to hypertension such as cerebral hemorrhage, cerebral small vessel disease, heart failure, atrial fibrillation, and renal failure.2, 3

In order to test and verify the current stratification of cardiovascular risk of 2010 Chinese Hypertension Guideline,4 Cohort Study of Cardiovascular Risk Stratification in Chinese Hypertensive Patients (cRisk study) was undertaken, which perspectively observed the incidence rates of cardiovascular events in groups among the different BP levels and different CV risk of Chinese hypertensive patients. A total of 3840 cases (45 ~ 64 years) of hypertensive patients were selected and enrolled from 13 centers in China in 2013. All patients were grouped with no risk factor, risk factors or target organ damage and complications in each BP level and were divided into the different risks, All endpoints were recorded each year, including stroke, coronary heart disease (CHD), atrial fibrillation (AF), heart failure (HF), end stage of renal disease (ESRD, and all cause death during follow‐up. Now, the mid‐term results of accumulating incidence rates (2014 ~ 2016) were reported and analyzed.5 Patients with 1, 2, and 3 grade for BP level were 1924,1239, and 677 cases, and patients with low, moderate, high, and very high group for CV risk were 241,646,1043, and 1910 cases, respectively. Incidence rates of endpoints were 5.5%, 4.6%, and 4.9% each year, respectively (2014 ~ 2016). The accumulating incidence rates were 10.3% (1 grade), 10.5% (2 grade), and 13.3% (3 grade) according to the BP levels with no statistical significances, and the accumulating incidence rates were 4.6% (low), 7.7% (moderate), 9.0% (high), and 16.5% (very high) according to the CV risk groups with statistical significances (P < .01), during 3 years follow‐up. The mid‐term results of this study indicate that CV risk stratification of 2010 Chinese Hypertension Guideline would be concordant with the real‐world practice. 6 It is very important to notice that middle‐aged patients with grade 1 or 2 hypertension, who are the majority of hypertensive population, may be classified as low risk, moderate risk, high risk, or very high risk, even if their blood pressure are at the same level. 7

It is necessary to acknowledge that the current basis and methods of risk stratification is still imperfect, not simple and convenient enough as well. It is not accurate enough for risk stratification since the evaluation of several risk factors need not only be qualitative, but also be quantitative, such as blood lipids, blood glucose, obesity, and other factors. These factors should be continuously updated. Long‐term observation of the actual cardiovascular risk status of patients at different risk levels in large populations of hypertension is an important way to correct and improve the current risk stratification.

Zhang W. Cardiovascular risk stratification in Chinese patients with hypertension. J Clin Hypertens. 2019;21:1607–1608. 10.1111/jch.13680