Abstract
BACKGROUND: Chronic kidney disease (CKD) carries the highest population attributable risk for mortality among all comorbidities in chronic heart failure (CHF). No studies about the association between inferior vena cava (IVC) diameter and all-cause mortality in patients with the comorbidity of CKD and CHF has been published. METHODS: In this retrospective cohort study, a total of 1327 patients with CHF and CKD were included. All patients underwent standardized echocardiography examination and data on demographic characteristics, medical history, and laboratory tests were recorded. Information on all-cause mortality was collected by telephone interview and medical records review. We used Cox regression to evaluate the risk of all-cause mortality among groups, and used mediation analysis to examine the mediation role of N-terminal-pro-B-type natriuretic peptide (NT-proBNP) and serum albumin in the association between IVC and all-cause mortality. RESULTS: During a median follow-up of 3.46 years (IQR: 1.55-5.15 years), 757 (57.05%) cases of all-cause mortality were observed. Compared with patients with IVC diameter < 21 mm, those with IVC diameter > 21 mm were associated with higher risk of all-cause mortality (HR (95%CI):1.31(1.07-1.61), log rank: P = 0.01) and cardiovascular mortality (HR (95%CI): 1.55(1.19-2.04), log rank: P = 0.001). When assessing IVC as a continuous variable, each 1% increase in IVC was associated with 4% increased risk of all-cause mortality (HR: 1.04, 95%CI 1.02-1.06, P < 0.001). This association were mediated by log NT-proBNP (mediated effect: 37.8% (95%CI 22.0-73.0%), P < 0.001) and serum albumin (mediated effect: 14.1% (95%CI 6.2-28.0%), P < 0.001). In subgroup analyses, there was no significant interaction in different subgroups of cardiac and renal function for the association between IVC and all-cause mortality. CONCLUSIONS: Elevated IVC diameter was associated with worse prognosis in patients with CHF and CKD, and the associations were mediated by log NT-proBNP and serum albumin.