Association of body mass index and uncontrolled blood pressure with cardiovascular mortality in peritoneal dialysis patients

The association of body mass index (BMI) and blood pressure (BP) control and their interaction with cardiovascular (CV) mortality in continuous ambulatory peritoneal dialysis (CAPD) patients is unclear. We retrospectively analyzed a consecutive series of 1595 incident CAPD patients with hypertension from 2006 to 2013, and followed up through December 2015. The BMI was categorized according to the World Health Organization classification for Asian population. Binary logistic regression was used to assess the relationship between BMI and BP control. Cox's proportional hazards models and competing risk analyses were performed to examine the nassociation of BMI and BP control with CV mortality. In the entire cohort, obesity was unlikely related to increased risk of uncontrolled BP. However, the adjusted hazard ratio (AHR) of CV mortality was increased in individuals with obesity when compared to those with normal weight (AHR 1.56; 95% confidence interval (CI) 1.04-2.34) and in individuals with uncontrolled BP when compared to those with controlled BP (AHR 1.39; (1.02-1.89)). Subgroup analyses showed that the combination of obesity and uncontrolled BP was associated with an increased risk for CV death, when compared to normal weight subjects with uncontrolled BP (AHR 2.35; (1.43-3.86)). Further, subjects with obesity and uncontrolled BP had a nearly threefold increase in risk (AHR 2.57; (1.57-4.20)) for CV death compared to subjects with neither risk factor. These associations persisted in competing risk analyses. In conclusion, the association of obesity with CV mortality was likely to vary with hypertension status among CAPD patients.