Abdominal aortic calcification score predicts cardiovascular outcome in peritoneal dialysis patients

Abstract

Objective To explore the association of abdominal aortic calcification score (AACS) with cardiovascular disease (CVD) outcomes in peritoneal dialysis (PD) patients. Methods The patients who underwent regular PD at Renji Hospital between July 2011 and July 2014 were recruited and prospectively followed up until the end of the study (August 31, 2018), death, or dropout PD. Abdomen lateral X-ray was used to determine AACS for each patient at enrollment. Patients were divided into three groups based on the tertiles of AACS: non-calcified group, AACS group (AACS=0), mild-moderate calcification group AACS group (0<AACS≤4) and severe calcification group (4<AACS≤24). Cumulative incidences of cardiovascular outcomes among three groups were estimated using competing risk model and compared through Gray test. Competing risk regression model was used to evaluate the association of AACS and cardiovascular events as well as CVD mortality. Results Two hundred and ninety-two PD patients were enrolled in this study. The cohort consisted of 160 males (54.8%) with the age (57.1±15.2) years and median PD vintage 28.4 (IQR 12.0, 57.8) months, and their average AACS was 2.0 (0.0, 6.0). Order logistic regression analysis showed that older age (OR=1.081, 95%CI 1.057-1.106, P<0.001) and longer PD vintage (OR=1.012, 95%CI 1.004-1.019, P=0.003), CVD history (OR=1.919, 95%CI 1.108-3.325, P=0.020) and diabetes (OR=2.554, 95%CI 1.415-4.609, P=0.002) were independent risk factors of escalating AACS in PD patients. During the follow-up, 65 cases CVD events and 50 cases CVD-related deaths developed. Patients in the upper AACS tertile had significantly higher estimated cumulative incidences of CVD occurrence (Gray=27.81, P<0.001) and CVD mortality (Gray=20.91, P<0.001). AACS was an independent predictor of both CVD occurrence (medium AACS group vs low AACS group: SHR=2.823, 95%CI 1.333-5.970, P=0.007; high AACS group vs medium AACS group: SHR=3.063, 95%CI 1.460-6.430, P=0.003) and CVD mortality (SHR=2.590, 95%CI 1.132-5.920, P=0.024) in competing risk regression models. Conclusions Age, PD vintage, diabetes and preexisting CVD are associated with higher AACS in the present cohort. AACS can predict CVD morbidity and mortality in PD population and therefore may help with the early identification of PD patients with adverse cardiovascular outcomes. Key words: Vascular calcification; Aorta, abdominal; Peritoneal dialysis; Cardiovascular disease; Mortality