Long-Term Body Mass Index Variability, Weight Change Slope, and Risk of Cardiovascular Outcomes: 7-Year Prospective Study in Chinese Hypertensive Subjects

Abstract

Background: The relationship between long-term body mass index (BMI) variability, weight change slope, and risk of cardiovascular outcomes in Chinese hypertensive patients has not been fully elucidated. Methods: A total of 20,737 patients with hypertension and three BMI measurements between 2006 and 2011 were included. Average real variability (ARV) was used to evaluate variability, and the subjects were divided into three groups: tertile 1 with BMI_ARV ≤0.86; tertile 2 with 0.86 < BMI_ARV ≤ 1.60; and tertile 3 with BMI_ARV >1.60. Cox proportional-hazards models were used to analyze the risk of cardiovascular and cerebrovascular diseases (CVD) in each group. Results: There were 1,352 cases of CVD during an average follow-up of 6.62 years. The 7-year cumulative incidence rates of CVD, stroke, and myocardial infarction (MI) in tertile 3 were 7.53, 6.13, and 1.56%, respectively. After adjustment for average BMI, weight change slope, and other traditional risk factors, the hazard ratio (HR) values for CVD, stroke, and MI in the highest tertile were 1.21 (95% CI 1.05-1.39), 1.21 (95% CI 1.04-1.38), and 1.20 (95% CI 0.88-1.62), respectively. Subgroup analysis showed that the HR values for CVD in tertile 3 were 1.71 (95% CI 1.06-2.75) and 0.98 (95% CI 0.61-1.58) in the positive and the negative weight change subjects, respectively. Conclusions: Higher BMI variability was associated with increased risk of CVD in hypertensive subjects with weight gain but not in those with weight loss, independent of traditional cardiovascular risk factors.