J-shaped association between the visceral adiposity index and all-cause mortality in patients with chronic kidney disease.

OBJECTIVE: Visceral obesity, assessed using the visceral adiposity index (VAI), is related to mortality, but studies of populations with chronic kidney disease (CKD) are scarce. The aim of this study was to evaluate the relationship between VAI and all-cause mortality among individuals with CKD. METHODS: We retrospectively explored the relationship between VAI and risk for all-cause death by analyzing the data of 4145 patients with CKD who participated in the National Health and Nutrition Examination Survey (NHANES) 2001-2006. Patients were followed until December 31, 2015. RESULTS: After an average follow-up of 134.14 mo, 1034 (24.95%) deaths were recorded. Comparison of VAI quartiles with the reference showed an unstable association of VAI with all-cause mortality after adjusting for a wide range of potential confounders in Cox regression analysis. The correlation between VAI and mortality was J-shaped after applying the penalized spline method. Before the inflection point (VAI = 68.23), higher VAI had a protective effect against mortality (hazard ratio [HR], 0.47; 95% confidence interval [CI], 0.28-0.77). However, the risk for all-cause mortality gradually increased with the VAI (HR, 1.13; 95% CI, 1.05-1.21). CONCLUSION: Visceral obesity may influence the rate of all-cause mortality in a nonlinear manner in populations with CKD. Risk for death was higher with visceral fat deficiency than with excessive visceral fat deposition.

Serum Folate and All-Cause Mortality is of Non-Linear Relationship Among Population with Chronic Kidney Disease: A Retrospective Cohort Study.

AIM: A transition toward high serum folate concentrations has been noticed following the mandatory folate fortification. To explore this further, we studied the relationship between folate and health outcomes in population with chronic kidney disease (CKD). METHODS: We retrospectively explored the relationships between serum folate and risk of all-cause death in this population. We analyzed data of 2142 subjects with CKD who participated in the National Health and Nutrition Examination Survey (NHANES) 1999-2006. Vital status was followed through December 31, 2006. RESULTS: Cox regression was used to estimate hazard ratios (HRs) of mortality for individuals with serum folate in rest quintiles compared with individuals with the fourth quintile. After an average follow-up of 57.4 months with 157 deaths recorded, a reversed J-shaped association was revealed after conducting multivariable adjustment. The mortality rate in population with lower and higher folate levels were 8.29% and 12.67%, respectively, and the corresponding adjusted HRs were 2.41 (95% confidence interval, CI=1.32-4.40) and 2.10 (1.20-3.70). Kaplan-Meier curve showed survival benefits for the fourth quintile of serum folate as compared to the first and fifth quintile. CONCLUSION: Serum folate concentrations may influence all-cause mortality in a non-linear pattern in the CKD population. It is reasonable to recommend periodic surveillance in the CKD population to maintain the serum folate concentration in an appropriate level.