Blood pressure and pulse pressure during long-term weight loss in the obese:: The Swedish Obese Subjects (SOS) Intervention Study

Objective: Recently we reported a complete relapse in the blood pressure (BP) of obese subjects despite a maintained 16% weight loss over 8 years. This relapse is now analyzed as a function of several variables. Pulse pressure (PP) is an independent risk factor of cardiovascular mortality. We now examine the development of PP in the obese and whether it can be modified by weight-reducing gastric surgery. Research Methods and Procedures: A total of 1157 patients treated with gastric surgery and 1031 obese controls (body mass index of 41.0 +/- 4.6 kg/m(2) [mean +/- SD], age 48 +/- 6 years) were followed for 5.5 +/- 2.1 (range 3 to 10) years. To separate the effect of weight change from effect of time on BP, the patients were divided in cohorts based on follow-up time. Results: Gastric surgery resulted in a maximum weight loss after 1 year that was followed by a moderate relapse. After 5.5 years, weight loss in the intervention group was 18 +/- 11% of initial body weight. Very little weight change was seen in controls. Systolic BP decreased in the intervention group during the first 6 months but had relapsed to control values at last examination. The adjusted change in PP was +4.7 mm Hg in obese controls but +2.9 mm Hg in the intervention group (p < 0.001). Final BP values were more closely related to follow-up time and ongoing weight increase than to initial body weight ol initial weight loss. Discussion: Effects of time (aging) and weight change per year on BP can be separated. An early increase in PP could be observed in the obese. This increase could be modified by weight-reducing gastric surgery.