Relationship between abdominal aortic calcification and outcomes in maintenance hemodialysis patients

Objective To investigate the relationship between abdominal aortic calcification (AAC) and outcomes in maintenance hemodialysis (MHD) patients. Methods One hundred and seventy MHD patients in the dialysis center of the Second Hospital of Tianjin Medical University from June 2014 and October 2014 were enrolled prospectively. Abdominal aortic calcification (AAC) was measured using AAC score (AACS) by abdominal lateral plain radiography. According to the AACS, the patients were divided into mild AAC (AACS＜5) group and severe AAC (AACS≥5) group for comparison, and Kaplan-Meier analysis was used to compare their survival rates. Multivariable COX regression models were used to determine the risk factors of all - cause mortality and cardiovascular disease mortality in MHD patients. Results Severe AAC (AACS≥5) was present in 28.2% (48/170) patients. The median follow-up duration was 25.6 (22.0, 26.0) months. During the follow-up, 6 patients (4.9%) in AACS＜5 group and 14 patients (29.2%) in AACS≥5 group died. Kaplan-Meier analysis showed that patients in AACS≥5 group had higher all-cause mortality rate and cardiovascular disease mortality rate as compared with patients in AACS＜5 group (χ2=9.746，P=0.002; χ2=9.697，P=0.002). Multivariate COX regression analysis demonstrated that high AACS (HR=4.373, 95%CI 1.562-7.246, P=0.005) and hypoproteinemia (HR=0.886, 95% CI 0.797 - 0.985, P=0.025) were independent risk factors for all-cause mortality, while hypoproteinemia (HR=0.829, 95%CI 0.718-0.956, P=0.010) and low 1,25(OH)D3 (HR=0.769, 95% CI 0.627 - 0.944, P=0.012) were independent risk factors for cardiovascular disease mortality. Conclusions AAC is significantly associated with overall survival in MHD patients. To further evaluate the relationship between AAC and outcomes in MHD patients, multi-center and long term follow up studies of large sample size are necessary.