High blood pressure declines and remains low after bariatric surgery

The prevalence of hypertension (high blood pressure) appears to decline and remain low after bariatric surgery, and blood pressure drops the most among patients who had untreated hypertension before the procedure, according to a study in the March issue of Archives of Surgery.

John D. Fernstrom, Ph.D., and colleagues at the University of Pittsburgh School of Medicine reviewed the medical charts of 347 patients who had undergone bariatric surgery between 1992 and 2001. Information about patients' weight loss, BMI, blood pressure and use of medications to control hypertension was recorded at follow-up visits in the 18 months after their procedures.

About half of the patients had hypertension before surgery and all had a beginning BMI of 40 or greater. After surgery, patients' BMI decreased and stabilized at around 35 after 18 months. Systolic (top number) blood pressure decreased modestly and diastolic (bottom number) blood pressure decreased significantly 18 months after surgery. Patients without hypertension and those taking antihypertensive medications experienced smaller drops in blood pressure than those with hypertension who were not taking medications. Of the 103 patients who were taking medications to control blood pressure before surgery, 35 were able to stop taking the drugs during follow-up, and their blood pressures remained in the normal range.

"Our findings are consistent with the notion that systolic and diastolic blood pressures improve when very obese individuals lose weight after bariatric surgery," the authors conclude. "The incidence of hypertension also declines, as reflected by the reduction in the number of individuals requiring antihypertensive medications to maintain a normal blood pressure and by the notable decline in systolic and diastolic blood pressure in subjects who had high blood pressure (stage 1 hypertension) but were unaware of it. However, the results cannot answer whether blood pressure and the incidence of hypertension ultimately return to presurgical levels; perhaps a future, prospective study will resolve this issue."