Serum 25-Hydroxyvitamin 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 including 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 measured by Standardized Outcomes in Nephrology-Hemodialysis (SONG-HD) fatigue measure; fatigue at the end of hemodialysis was measured 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) was negatively correlated with SONG-HD score (ß = -1.503, 95% CI: -2.826 to 0.18, p = 0.026) and NRS score (ß = -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. Interaction effects between age ≥65 years and lg(25[OH]D [nmol/L]) in terms of fatigue scores were significant based on multiple linear regressions (SONG-HD score ß = -3.613, p for interaction = 0.006; NRS score ß = -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] was negatively correlated with SONG-HD score (ß = -3.323, p = 0.010) and NRS score (ß = -3.521, p = 0.006) on univariate linear regressions. Following adjustment for sex, age, and all CKD-MBD characters, lg[25(OH)D] was negatively correlated with SONG-HD scores (multiple linear regression ß = -4.012, p = 0.004; multiple robust regression ß = -4.012, p = 0.003) or NRS scores (multiple linear regression ß = -4.104, p = 0.002; multiple robust regression ß = -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, on either univariate linear regressions or multiple regressions. CONCLUSION: Serum 25(OH)D level is negatively associated with fatigue in elderly MHD patients.

Precision and Reliability of Tightly Coupled PPP GNSS and Landmark Monocular Vision Positioning.

This paper presents an approach to analyse the quality, in terms of precision and reliability, of a system which integrates-at the observation-level-landmark positions and GNSS measurements, obtained with a single camera and a digital map, and a single frequency GNSS receiver respectively. We illustrate the analysis by means of design computations, and we present the actual performance by means of a small experiment in practice. It is shown that the integration model is able to produce a position solution even when both sensors individually fail to do so. With realistic assumptions on measurement noise, the proposed integrated, low-cost system can deliver a horizontal position with a precision of better than half a meter. The external reliability of the integrated system is at the few decimetre-level, showing that the impact of undetected faults in the measurements, for instance incorrectly identified landmarks in the image, on the horizontal position is limited and acceptable, thereby confirming the fault-robustness of the system.