The HOT Study: design and cost of major blood pressure trials

Low rate of resistant hypertension in Chinese patients with hypertension: an analysis of the HOT-CHINA study

Objective:

The rate of resistant hypertension in China is unknown. This is an analysis of resistant hypertension based on Hypertension Optimal Treatment Study in China.

Methods:

The study was conducted in 148 cities in mainland China from April 2001 to February 2002, which included 54 590 hypertensive patients (≥18 years of age), and used a five-step treatment programme. Patients not achieving blood pressure (BP) target (<140/90 mmHg) within 2 weeks received preplanned additional drugs. Resistant hypertension was defined in the participants with uncontrolled hypertension after 2 weeks of treatment on Step 5.

Results:

The rate of resistant hypertension was 1.9%. Patients with resistant hypertension were characterized by following features: higher male percentage (65.6 vs. 60.2%); younger age (59.51 ± 13.02 vs. 61.76 ± 12.27 years); higher BMI (24.8 ± 3.5 vs. 24.0 ± 3.4 kg/m²); longer disease course; higher fasting blood glucose (6.60 ± 2.69 vs. 5.99 ± 2.12 mmol/l); higher total cholesterol (5.67 ± 1.63 vs. 5.32 ± 1.24 mmol/l); higher triglycerides (2.15 ± 1.32 vs. 1.96 ± 1.09 mmol/l); and higher percentage of grade 3 hypertension (71.1 vs. 27.2%) (all P < 0.001). Patients with resistant hypertension also had a higher rate of metabolic syndrome (45.9 vs. 35.4%), diabetes mellitus (25.5 vs. 14.7%) and history of myocardial infarction (4.7 vs. 3.3%) or stroke (17.0 vs. 11.6%) (P < 0.001). Multivariate analyses revealed an association of resistant hypertension with younger age, higher BP, BMI, longer disease course, higher fasting blood glucose and total cholesterol (P < 0.05).

Conclusion:

Resistant hypertension in Chinese patients is associated with overweight/obesity, higher BP and metabolic syndrome. The rate of resistant hypertension in China, however, is much lower than previously reported. Another intriguing characteristic is the association of resistant hypertension with younger age.

The Hypertension Optimal Treatment Study: what did it give us?

The Hypertension Optimal Treatment study was a large, randomized, multicenter study to determine the answers to two questions: 1) what is the optimal target blood pressure to be sought in the treatment of patients with moderate hypertension? and 2) does low dose aspirin therapy decrease morbidity and mortality in patients with hypertension? After 3.8 years of follow-up for the almost 19,000 patients, the following conclusions from the study could be ascertained 1) lowering diastolic blood pressure in patients with diabetes to levels below 80 mm Hg decreases the risk of major cardiovascular events and cardiovascular mortality compared with lowering it to "normal" (< 90 mm Hg) levels. It may lower total mortality, but this study was not powered for this end point; 2) aspirin therapy, in patients with hypertension, is safe and decreases major cardiovascular events and acute myocardial infarction; 3) there does not appear to be an additional effect on cardiovascular mortality or overall mortality below that observed with a reduction of diastolic blood pressure to less than 90 mm Hg for the population as a whole; and 4) the lowest cardiovascular event rate for the population as a whole was achieved at a diastolic blood pressure of 83 mm Hg. Several limitations to this study exist, including the low event rate achieved and the generalizability of this study to the average nondiabetic patient with hypertension seen in clinical practice.