A controlled clinical trial of the effect of gastric bypass surgery and intensive lifestyle intervention on nocturnal hypertension and the circadian blood pressure rhythm in patients with morbid obesity

BackgroundNocturnal hypertension, increased night-to-day systolic blood pressure (BP) ratio and nondipper status (night-to-day systolic BP ratio > 0.9) are associated with an increased risk of cardiovascular disease. Our aim was to compare the 1-year effect of Roux-en-Y gastric bypass (RYGB) versus a program of intensive lifestyle intervention (ILI) only on nocturnal hypertension and circadian BP rhythm.MethodsThe study participants were part of a 1-year, controlled clinical trial comparing the effect of RYGB or ILI on obesity-related comorbidities. Ninety participants (49 in the RYGB group) successfully completed 24-hour ambulatory BP monitoring at baseline and follow-up and were eligible subsequently for analysis.ResultsA total of 71 subjects (79%) had nocturnal hypertension at baseline. The number of subjects with nocturnal hypertension decreased from 42 to 14 in the RYGB group (P ≤ .001) and from 29 to 27 (P = .791) in the ILI group. Subjects in the RYGB group had a lesser adjusted odds ratio (OR) of nocturnal hypertension at follow-up (OR 0.15; 95% confidence interval, 0.05–0.42; P ≤ .001); however, after further adjustment for weight loss, there was no additional beneficial effect of RYGB (P = .674). No differences between groups regarding improvement in the night-to-day systolic BP ratio were found after adjustment for 24-hour systolic pressure (P = .107). Both interventions showed a decrease in the proportion of subjects classified as nondippers, namely, 44% (P ≤ .001) and 28% (P = .002) in the RYGB and ILI groups, respectively.ConclusionOnly RYGB was associated with a decrease in the prevalence of nocturnal hypertension. Both interventions showed an improvement in dipper status, although RYGB was more effective.