Tuesday, 5 February 2013

Chinese trial will answer question of whether to treat pre-hypertension

There's an air of impatience clouding the 2013 International Conference on Prehypertension and Cardiometabolic Syndrome. Most patients diagnosed with higher-than-optimal blood pressure will go on to develop hypertension, but there are no good data to suggest if or how this can be averted.
That frustrates experts gathered here, some of whom say they can't wait for results from ongoing clinical trials—they are proceeding with low-dose pharmacological treatment in select high-risk patients.
"If we wait for the evidence, we'll all be buried before the evidence is in," Dr Flavio Fuchs (Hospital de Clinicas de Port Alegre, Brazil) pronounced. "Four out of five prehypertensives will be hypertensive by age 60. . . . For my [prehypertensive] patients, I am offering the option of using low-dose drugs if they are close to becoming hypertensive."
Dr Stevo Julius (University of Michigan, Ann Arbor) put it more bluntly: "If your brother had prehypertension, you would treat him."
But Dr Yuqing Zhang (Fu Wai Hospital, Beijing, China) pointed out that it is not just the question of drug efficacy in high-normal BP, "we also need to answer the question of cost-effectiveness, because the incidence of hard outcomes is very low in these subjects, maybe 7% per 100-person years. So much lower than in those with established hypertension—this is an area where we really need to get some answers."
Zhang is one of the investigators in the largest ongoing trial in this area, the Chinese High Normal Blood Pressure (CHINOM) trial. The study has finished enrollment of 10 689 patients with blood pressure in the range of 130-139/85-89 mm Hg and at least one other cardiovascular disease risk factor (but no established diabetes, renal or hepatic dysfunction, or history of stroke or CVD).
Presenting an overview of the study here, Zhang explained that patients are being randomized to one of three parallel treatment groups: telmisartan 40 mg, indapamide 1.5 mg, or, in the third group, placebo or a combination pill of hydrochlorothiazide 12.5 mg, triamterene 12.5 mg, dihydralazine 12.5 mg, and reserpine 0.1 mg. The primary end point of the study is combined CV events (nonfatal stroke, nonfatal MI, and CVD death), while a secondary end point addresses new-onset hypertension and new-onset diabetes.
While the first results are still several years away, baseline characteristics of study subjects are already revealing. For example, he noted, 70% of subjects enrolled actually have more than one CV risk factor, with metabolic syndrome being the most common. More than three-quarters of participants are overweight or obese, 42% have high triglycerides, and over one-third have a family history of hypertension.
"This is not a benign population," he said.
Importantly, Zhang said, a family history of stroke is more than twice as common in the CHINOM cohort as a family history of MI (12% vs 5%).
Investigators plan to do an interim analysis when they've accumulated 100 events; they are just shy of 90 now, Zhang said.
Source: theheart.org

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