Severely obese patients may experience significant, long-term improvements in blood pressure as they lose substantial amounts of weight after gastric bypass surgery, thereby contributing to their overall health, according to a new University of Pittsburgh study, published in the March issue of the Archives of Surgery. Excess body weight is associated with a host of health complications including diabetes, certain cancers and joint stress, with nearly two-thirds of very obese patients suffering from high blood pressure -- the primary risk factor for both stroke and heart disease.
John Fernstrom, Ph.D., professor of psychiatry, pharmacology and neuroscience at the University of Pittsburgh School of Medicine and research director of the University of Pittsburgh Medical Center (UPMC) Weight Management Center, and colleagues analyzed data from 347 patients at the upper extreme of body weight, with a beginning Body Mass Index (BMI) of greater than 40 who underwent gastric bypass surgery at UPMC between 1992 and 2001.
BMI is a height-to-weight ratio that determines a patient's degree of obesity. A BMI less than 25 is considered to be a healthy weight, while a BMI of 40 or greater is categorized as extreme obesity. At the time of data analysis, 18 months after surgery, study patients' BMIs had stabilized to about 35 -- still categorized as obese.
Half of the study patients were classed as hypertensive prior to gastric bypass surgery. Of those, some were unmedicated and had high blood pressure while others were being treated for their hypertension. The patients who were not being treated for hypertension prior to surgery experienced significant blood pressure decreases that continued to remain low 18 months after surgery. Of the patients under active drug treatment for hypertension prior to surgery, about one-third were able to reduce or eliminate their blood pressure medications after surgery. The group of patients with normal blood pressure who were taking no blood pressure medications before surgery showed insignificant changes following surgery.
"These results suggest that the blood pressure status of patients prior to gastric bypass surgery may give us good and realistic indicators of those patients who are likely to experience substantial improvements in blood pressure after surgery over the long term and who may, as a result, avoid cardiovascular disease or stroke," noted Dr. Fernstrom. "Our data also indicate that following surgery, certain patients may no longer need the medications they were taking to control their blood pressure prior to surgery," he said.
"Extremely obese patients have great difficulty reducing their body weight through lifestyle changes and pharmacotherapy, so their overall health remains compromised and high blood pressure represents a serious health problem. In counseling patients who are considering gastric bypass surgery, this study will help us to identify those patients who can reasonably expect the long-lasting health benefits from significantly reduced blood pressure," said study co-author Madelyn Fernstrom, Ph.D., associate professor of psychiatry, epidemiology and surgery at the University of Pittsburgh School of Medicine and director of the UPMC Weight Management Center.
"For those severely overweight patients with elevated blood pressure, or under treatment for elevated blood pressure, bariatric surgery offers the promise of improved health, with not only substantial and sustained weight loss, but also the added benefit of significant blood pressure improvements," said study co-author Anita Courcoulas, M.D., associate professor of surgery at the University of Pittsburgh School of Medicine and director of the Minimally Invasive Bariatric and General Surgery program at UPMC.
"It also is important to note that blood pressure reductions occurred in patients even though they remained obese with BMIs in the 35 range, which is still not ideal, further suggesting that weight loss itself -- in this study, achieved through gastric bypass surgery -- can improve health outcomes," commented Dr. Madelyn Fernstrom.
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