Salt-resistant and salt-sensitive phenotypes determine the sensitivity of blood pressure to weight loss in overweight/obese patients

High blood pressure (BP) is extremely common in persons with obesity. However, not all obese individuals have high BP, nor does weight loss lower BP in all persons. In this study, the authors investigated whether the salt-sensitive (SS) or salt-resistant (SR) phenotype determines the degree of BP lowering induced by weight loss in a group of middle-aged individuals of whom 80% are of Hispanic descent. Overweight/obese participants classified as SS or SR (N=45; body mass index, 27-35 kg/m2) entered a 1-year program of dietary restriction, aerobic exercise, and metformin therapy. Comparable reductions in obesity (8%-10%), triglycerides (25%), and fasting insulin concentrations (40%) were observed in SR and SS individuals. In SS patients, the intervention lowered systolic BP/diastolic BP by 8.8/6.1 mm Hg, decreased albuminuria by 63%, and decreased the patient's salt sensitivity. Neither BP nor albuminuria was modified in SR persons by the intervention. In obese SS individuals, salt restriction induced comparable BP lowering as weight reduction. In summary, BP lowering induced by the lifestyle/metformin intervention appears to be determined by the SR/SS phenotype. Weight loss and correction of metabolic abnormalities lowers BP in obese SS persons but not in obese SR persons. Correcting adiposity in SS patients lowers BP by making the BP insensitive to dietary salt. The SR phenotype protects from obesity-induced increases in BP.