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BACKGROUND/AIMS: Cardiovascular disease and protein-energy wasting are among the strongest predictors of the high mortality of dialysis patients. In the general population, the novel cardiovascular and wasting biomarker, growth differentiation factor 15 (GDF15), is associated with decreased survival. However, little is known about GDF15 in dialysis patients. METHODS: Among prevalent hemodialysis patients participating in a prospective study (October 2011 to August 2015), we examined the association of baseline GDF15 levels with all-cause mortality using unadjusted and case mix-adjusted death hazard ratios (HRs) that controlled for age, sex, race, ethnicity, diabetes, and dialysis vintage. RESULTS: The mean age ± SD of the 203 patients included in the study was 53.2 ± 14.5 years, and the cohort included 41% females, 34% African-Americans, and 48% Hispanics. GDF15 levels (mean ± SD 5.94 ± 3.90 ng/mL; range 1.58-39.8 ng/mL) were higher among older patients and were inversely associated with serum creatinine concentrations as a surrogate for muscle mass. Each 1.0 ng/mL increase in GDF15 was associated with an approximately 17-18% higher mortality risk in the unadjusted and case mix models (p < 0.05). Increments of about 1 SD (a 4.0 ng/mL increase in GDF15) were associated with a nearly 2-fold higher death risk. The highest GDF15 tertile was associated with higher mortality risk (reference: lowest tertile): the HRs (95% CI) were 3.19 (1.35-7.55) and 2.45 (1.00-6.00) in the unadjusted and the case mix-adjusted model, respectively. These incremental death trends were confirmed in cubic spline models. CONCLUSION: Higher circulating GDF15 levels are associated with higher mortality risk in hemodialysis patients. Future studies are needed to determine whether GDF15 may represent a novel therapeutic target for cardiovascular disease, wasting, and death in this population.
RESUMEN
PRIMARY OBJECTIVE: In a cross-over randomized pilot study, the relative absorption of vitamins C, B(6) and B(12) were tested using a commercial vitamin-water (VW) and a standardized mixed meal (MM). METHODS AND PROCEDURES: Twelve adults (22.9+/-3.7 years), received the VW and the MM, randomly ordered, with a minimum 7-day washout period between. Blood was drawn pre-ingestion and over a post-ingestion period of 300+ min. Test meal quantities were formulated to contain equal amounts of vitamins B(6), B(12), and C as per the water label. Analysis revealed that a scaling factor had to be used to balance the actual content differences between test products. MAIN OUTCOMES AND RESULTS: Using the adjusted numbers for actual water vitamin concentration, there were no differences in the maximum concentration and the 5-h area under the curve for vitamins B(6), B(12) or C between the VW and the MM. CONCLUSIONS: VW was found to provide similar in vivo nutrition as the test MM at a caloric saving.
