Evaluating Osteoporosis in Chronic Kidney Disease: Both Bone Quantity and Quality Matter.

Bone strength is determined not only by bone quantity [bone mineral density (BMD)] but also by bone quality, including matrix composition, collagen fiber arrangement, microarchitecture, geometry, mineralization, and bone turnover, among others. These aspects influence elasticity, the load-bearing and repair capacity of bone, and microcrack propagation and are thus key to fractures and their avoidance. In chronic kidney disease (CKD)-associated osteoporosis, factors traditionally associated with a lower bone mass (advanced age or hypogonadism) often coexist with non-traditional factors specific to CKD (uremic toxins or renal osteodystrophy, among others), which will have an impact on bone quality. The gold standard for measuring BMD is dual-energy X-ray absorptiometry, which is widely accepted in the general population and is also capable of predicting fracture risk in CKD. Nevertheless, a significant number of fractures occur in the absence of densitometric World Health Organization (WHO) criteria for osteoporosis, suggesting that methods that also evaluate bone quality need to be considered in order to achieve a comprehensive assessment of fracture risk. The techniques for measuring bone quality are limited by their high cost or invasive nature, which has prevented their implementation in clinical practice. A bone biopsy, high-resolution peripheral quantitative computed tomography, and impact microindentation are some of the methods established to assess bone quality. Herein, we review the current evidence in the literature with the aim of exploring the factors that affect both bone quality and bone quantity in CKD and describing available techniques to assess them.

Vitamin D and Chronic Kidney Disease Association with Mineral and Bone Disorder: An Appraisal of Tangled Guidelines.

Chronic kidney disease (CKD) is a highly prevalent condition worldwide in which the kidneys lose many abilities, such as the regulation of vitamin D (VD) metabolism. Moreover, people with CKD are at a higher risk of multifactorial VD deficiency, which has been extensively associated with poor outcomes, including bone disease, cardiovascular disease, and higher mortality. Evidence is abundant in terms of the association of negative outcomes with low levels of VD, but recent studies have lowered previous high expectations regarding the beneficial effects of VD supplementation in the general population. Although controversies still exist, the diagnosis and treatment of VD have not been excluded from nephrology guidelines, and much data still supports VD supplementation in CKD patients. In this narrative review, we briefly summarize evolving controversies and useful clinical approaches, underscoring that the adverse effects of VD derivatives must be balanced against the need for effective prevention of progressive and severe secondary hyperparathyroidism. Guidelines vary, but there seems to be general agreement that VD deficiency should be avoided in CKD patients, and it is likely that one should not wait until severe SHPT is present before cautiously starting VD derivatives. Furthermore, it is emphasized that the goal should not be the complete normalization of parathyroid hormone (PTH) levels. New developments may help us to better define optimal VD and PTH at different CKD stages, but large trials are still needed to confirm that VD and precise control of these and other CKD-MBD biomarkers are unequivocally related to improved hard outcomes in this population.

The impact of COVID-19 in hemodialysis patients: Experience in a hospital dialysis unit.

INTRODUCTION: COVID-19 is a very high transmission disease with a variable prognosis in the general population. Patients in hemodialysis therapy are particularly vulnerable to developing an infectious disease, but the incidence and prognosis of hemodialysis patients with COVID-19 is still unclear. The main objective is to describe the experience of our dialysis unit in preventing and controlling the spread of SARS-CoV-2 infection. METHODS: Preventive structural and organizational changes were applied to all patients and health care personnel in order to limit the risk of local transmission of SARS-CoV-2 infection. FINDINGS: The Nephrology department at Sant Joan Despí Moises Broggi Hospital-Consorci Sanitari Integral is a reference for two satellite hemodialysis centers caring for 156 patients. We combine our own hemodialysis maintenance program for 87 patients with hospitalized patients from peripheral hemodialysis centers. In this area, the reported incident rate of COVID-19 in these peripherical hemodialysis centers was 9.5% to 19.9% and the death rate 25% to 30.5%. In our hemodialysis program, the incidence rate was 5.7%. Three out of five required hospitalization (60%) and nobody died. DISCUSSION: Although the risk of local transmission of the disease was very high due to the increase in hemodialysis patients from peripheral centers admitted to hospital, the incidence rate of COVID-19 was very low in our own hemodialysis patients. We believe that the structural and organizational changes adopted early on and the diagnosis algorithm played an important role in minimizing the spread of the disease.

Are Currently Used Bioimpedance Methods in Hemodialysis Comparable for Calculating Dialysis Dose?

Bioelectrical impedance analysis has increasingly been incorporated into hemodialysis units (HD) as a useful, noninvasive technique for evaluating overall fluid status. The aims of this study were to verify whether the information obtained from two different bioelectrical impedance analysis methods (spectroscopy bioimpedance [BCM] and single-frequency bioelectric impedance vector analysis [SF-BIVA]) was comparable for analyzing fluid status, and to determine their impact when used to calculate dialysis dose. This observational cross-sectional study included 78 HD patients who underwent one measurement with BCM and one with SF-BIVA in the same dialysis session. For calculating the dialysis dose, total body water or urea distribution volume (V) was calculated by the Watson formula and compared with the V obtained from the two devices. The difference in V between the two devices was 5.4 L (P < 0.001). Given the existent correlation between VBCM and VSF-BIVA , we were able to apply a formula (corrected V = VSF-BIVA = 1.04 × VBCM + 4.85, r = 0.93), allowing comparison of the two bioimpedance methods. The mean dialysis dose for BCM device (KtID /VBCM ) was 2.49 ± 0.85, much higher than KtID /VSF-BIVA (2.06 ± 0.72) mainly due to the V obtained with the different devices, with KtID /VWatson being 2.03 ± 0.67. The results on volume distribution showed an acceptable correlation but the devices were not comparable due to intermethod differences observed. Dialysis centers using SF-BIVA will obtain much lower dialysis dose, but by applying our formula, the Kt/V would resemble that obtained by the BCM device.

Sensitivity of blood volume monitoring for fluid status assessment in hemodialysis patients.

BACKGROUND/AIMS: This study investigates the use of blood volume monitoring (BVM) markers for the assessment of fluid status. METHODS: Predialysis fluid overload (FO) and BVM data were collected in 55 chronic hemodialysis patients in 317 treatments. Predialysis FO was measured using bioimpedance spectroscopy. The slope of the intravascular volume decrease over time normalized by ultrafiltration rate (Slope4h) was used as the primary BVM marker and compared against FO. RESULTS: Average relative blood volume curves were well separated in different FO groups between 0 and 5 liters. Receiver-operating characteristics analysis revealed that the sensitivity of BVM was moderate in median FO ranges between 1 and 3 liters (AUC 0.60-0.65), slightly higher for volume depletion of FO <1 liter (AUC 0.7) and highest for excess fluid of FO >3 liters (AUC 0.85). CONCLUSION: Devices that monitor blood volume are well suited to detect high FO, but are not as sensitive at moderate or low levels of fluid status.