Kidney Week

Abstract: SA-PO692

Free 25(OH) Vitamin D and Mortality Among Hemodialysis Patients

Session Information

• Bone and Mineral Metabolism: Clinical - II
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Novel-Catin, Etienne, University Center Hospital - Lyon Sud, Saint Priest, France

Etienne Novel-Catin,

• Koppe, Laetitia, University Center Hospital - Lyon Sud, Saint Priest, France

Laetitia Koppe,

• Bouchara, Anaïs, University Center Hospital - Lyon Sud, Saint Priest, France

Anaïs Bouchara,

• Carlier, Marie-christine, University Center Hospital - Lyon Sud, Saint Priest, France

Marie-christine Carlier,

• Pastural, Myriam, AURAL, LYON, France

Myriam Pastural,

• Samuel, Granjon, Cerballiance laboratory, Lyon, France

Granjon Samuel,

• Szelag, Jean-christophe, AURAL, LYON, France

Jean-christophe Szelag,

• Laville, Maurice, University Center Hospital - Lyon Sud, Saint Priest, France

Maurice Laville,

• Fouque, Denis, University Center Hospital - Lyon Sud, Saint Priest, France

Denis Fouque,

• Pelletier, Solenne, University Center Hospital - Lyon Sud, Saint Priest, France

Solenne Pelletier,

Background

Most of the circulating 25-(OH) vitamin D (abbreviated 25(OH)D) is bound to proteins. Free vitamin D represents only 1% of the circulating vitamin D. There is abundant evidence that this free faction is the bioactive form of vitamin D. Total 25(OH)D deficiency has been associated with early mortality and cardiovascular events (CV) in chronic kidney disease (CKD) patients. The aim of the present study was to investigate a potential association between serum free 25(OH)D levels and i) other biochemical parameters of mineral metabolism, (ii) CV events and (iii) mortality.

Methods

253 patients undergoing maintenance hemodialysis (HD) were included. Serum free 25(OH)D measurement by ELISA (Diasource® Leuven, Belgium) as well as routine biochemistry tests were performed. Enrolled patients were prospectively monitored for cardiovascular (CV) events and mortality.

Results

During a mean study period of 2.5 years, 48 patients died and 60 suffered from a CV event. Median serum free 25(OH)D was 6.01 pg/ml [4.67 – 7.39] and median total 25(OH)D was 32.2µg/l [24.8-39.9]. Free 25(OH)D was strongly associated with total 25(OH)D (r= 0.77, p < 0.01). Free 25(OH)D was positively associated with serum calcium levels (r= 0.29, p<0.01) and negatively with serum PTH (r= - 0.19, p<0.01). Kaplan-Meier analysis showed no significant association between below median free 25(OH) and all-cause mortality (log rank, p=0.25, see figure 1) nor CV events (log rank, p=0.91).

Conclusion

This is the first study reporting survival depending on free 25(OH)D status in maintenance dialysis patients. It shows that free 25(OH)D levels are not associated with mortality nor cardiovascular events among maintenance HD patients. Our data concur with precedent results showing that bioavailable vitamin D is positively associated with calcium levels and negatively associated with serum PTH.