Retinoic acid associates with mortality of patients on long-term hemodialysis

BACKGROUND: Retinol concentrations in serum are significantly higher in patients on hemodialysis (HD) compared to healthy controls. Its lower concentrations have been reported to be an independent predictor of mortality. ATRA – all-trans retinoic acid – is an important compound related to retinol. The objective was to determine ATRA concentrations in serum and to find their association with the prognosis of patients on long-term HD. METHODS: ATRA was determined by high-performance liquid chromatography in a group of 247 HD patients (follow-up five years) and 54 healthy controls. RESULTS: Although serum retinol concentrations were higher in the studied cohort of HD patients, ATRA was lower – median 1.13 (interquartile range 0.90–1.60) ng/mL in HD patients versus 1.42 (1.08–1.63) ng/mL in healthy controls, p = 0.02. Lower ATRA was significantly related to overall mortality of HD patients (HR (95%CI) 0.63 (0.47–0.85) per interquartile range, p = 0.003). The best prognosis was observed in patients with concentrations of both ATRA and retinol above the median (p = 0.003). CONCLUSIONS: We detected decreased retinoic acid levels in HD patients compared to healthy controls. Lower concentrations of ATRA represent a significant predictor of mortality and provide additional information to retinol.