Serum 25(OH)D level is negatively associated with fatigue in elderly maintenance hemodialysis patients

Introduction: Chronic kidney disease-mineral and bone disorder (CKD-MBD) is frequently observed in maintenance hemodialysis (MHD) patients, and is associated with fracture, muscle weakness, malnutrition, etc.; however, relationships of CKD-MBD markers and fatigue are not well established. Methods: This was a cross-sectional study included 244 MHD patients (89 elders) from July to September 2021 in The First Affiliated Hospital of Shandong First Medical University. CKD-MBD markers and other clinical data were collected from medical records. Fatigue in the past week was measure by Standardized Outcomes in Nephrology-Hemodialysis (SONG-HD) fatigue measure; fatigue at the end of hemodialysis was measure by numeric rating scale (NRS). Spearman correlation, linear regression and robust linear regression were. Results: In all MHD patients, Lg(25(OH)D(nmol/L) were negatively correlated with SONG-HD score (beta=-1.503, 95%CI: -2.826--0.18, P=0.026) and NRS score (beta=-1.532, P=0.04) in multiple regression models adjusting for sex, age and all CKD-MBD characters; but no correlations were found on univariate regression or in other multiple regression models. Interactions effects between age >= 65years and Lg(25(OH)D(nmol/L)) in terms of fatigue scores were significant base on multiple linear regressions (SONG-HD score beta=-3.613, P for interaction =0.006; NRS score beta=-3.943, P for interaction=0.008). Compared with non-elderly patients, elderly patients were with higher ACCI scores(7(6, 8) VS 4(3, 5), P<0.001), higher SONG-HD scores (3(2,6) VS 2(1,3), P<0.001), higher NRS score (4(2, 7) VS 3(1, 5), P<0.001), lower serum phosphate levels (1.65(1.29, 2.10) VS 1.87(1.55, 2.26) mmol/L, P=0.002), and lower serum iPTH levels (160.6(90.46,306.45) VS 282.2(139, 445.7) pg/ml, P<0.001). There were no differences in serum calcium, alkaline serum or 25(OH)D levels between the two groups. In elderly patients, lg(25(OH)D were negatively correlated with SONG-HD score (beta=-3.323, P=0.010) and NRS score (beta=-3.521, P=0.006) on univariate linear regressions. Following adjustment for sex, age and all CKD-MBD characters, lg(25(OH)D were negatively correlated with SONG-HD scores (multiple linear regression beta=-4.012, P=0.004; multiple robust regression beta=-4.012, P=0.003) or NRS scores (multiple linear regression beta=-4.104, P=0.002; multiple robust regression beta=-4.104, P=0.001). There were no significant correlations between fatigue scores and other CKD-MBD markers (calcium, phosphate, lgiPTH, alkaline phosphatase) in elderly MHD patients, either on univariate linear regressions or multiple regressions. Conclusion: Serum 25(OH)D level is negatively associated with fatigue in elderly maintenance hemodialysis patients.