Metabolic syndrome components signal resistant hypertension

By Eleanor McDermid, Senior medwireNews Reporter

Chinese patients with hypertension that is difficult to treat often have poor cardiometabolic profiles, shows an analysis of the HOT-CHINA study.

HOT-CHINA (Hypertension Optimal Treatment Study in China) was an observational study of hypertensive patients treated according to a five-step protocol. Just 1.9% of the 48,291 patients in the study who were treated according to protocol had resistant hypertension, which the researchers defined as elevated blood pressure despite treatment with at least three antihypertensives of different classes.

This rate is low compared with that reported in other studies, say study author Yuqing Zhang (Chinese Academy of Medical Sciences, Beijing) and colleagues. They attribute this to different study populations, saying that other studies typically enrolled a large proportion of patients at high cardiovascular risk.

In all, 45.9% of patients with resistant hypertension had the metabolic syndrome, compared with 35.4% of patients with treatable hypertension, and several components of the metabolic syndrome were significantly associated with an increased risk for resistant hypertension on multivariate analysis.

Specifically, higher body mass index, fasting blood glucose, and total cholesterol were associated with respective risk increases of 2% per 1 kg/m², and 4% and 14% per 1 mmol/L, and patients with grade 3 hypertension (≥180/110 mmHg) had a 39-fold increased risk relative to those with grade 1 hypertension.

The duration of hypertension also affected treatment success; patients whose hypertension had lasted a year or longer had two- to threefold increases in the risk for resistant hypertension relative to those who had become hypertensive less than a year previously.

Unexpectedly, Zhang et al found that younger age was associated with resistant hypertension, despite elderly people usually being harder to treat because of factors such as arterial stiffness, organ damage, and comorbidities.

“This finding is counterintuitive, and may reflect the different lifestyle in elderly vs. young Chinese, for example, high alcohol and nicotine intake, high work pressure, neglect of health despite knowledge in young Chinese people,” they write in the Journal of Hypertension.

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