Iola Pinto

Higher Mineralized Bone Volume is Associated with a Lower Plain X-Ray Vascular Calcification Score in Hemodialysis Patients

Background and objectives In dialysis patients, there is an increasing evidence that altered bone metabolism is associated with cardiovascular calcifications. The main objective of this study was to analyse, in hemodialysis patients, the relationships between bone turnover, mineralization and volume, evaluated in bone biopsies, with a plain X-ray vascular calcification score. Design, setting, participants and measurements In a cross-sectional study, bone biopsies and evaluation of vascular calcifications were performed in fifty hemodialysis patients. Cancellous bone volume, mineralized bone volume, osteoid volume, activation frequency, bone formation rate/bone surface, osteoid thickness and mineralization lag time were determined by histomorphometry. Vascular calcifications were assessed by the simple vascular calcification score (SVCS) in plain X-Ray of pelvis and hands and, for comparison, by the Agatston score in Multi-Slice Computed Tomography (MSCT). Results SVCS≥3 was present in 20 patients (40%). Low and high bone turnover were present in 54% and 38% of patients, respectively. Low bone volume was present in 20% of patients. In multivariable analysis, higher age (p = 0.015) and longer hemodialysis duration (p = 0.017) were associated with SVCS≥3. Contrary to cancellous bone volume, the addition to this model of mineralized bone volume (OR = 0.863; 95%CI: 0.766, 0.971; p = 0.015), improved the performance of the model. For each increase of 1% in mineralized bone volume there was a 13.7% decrease in the odds of having SVCS≥3 (p = 0.015). An Agatston score>400 was observed in 80% of the patients with a SVCS≥3 versus 4% of patients with a SVCS<3, (p<0.001). Conclusion Higher mineralized bone volume was associated with a lower plain X-ray vascular calcification. This study corroborates the hypothesis of the existence of a link between bone and vessel and reinforces the clinical utility of this simple and inexpensive vascular calcification score in dialysis patients.

The risk of chronic kidney disease and mortality are increased after community-acquired acute kidney injury.

We investigated whether community-acquired acute kidney injury encountered in a tertiary hospital emergency department setting increases the risk of chronic kidney disease (CKD) and mortality, and whether plasma biomarkers could improve the prediction of those adverse outcomes. In a prospective cohort study, we enrolled 616 patients at admission to the emergency department and followed them for a median of 62.1 months. Within this cohort, 130 patients were adjudicated as having acute kidney injury, 159 transient azotemia, 15 stable CKD, and 312 normal renal function. Serum cystatin C and plasma neutrophil gelatinase-associated lipocalin (NGAL) were measured at index admission. After adjusting for clinical variables, the risk of developing CKD stage 3, as well as the risk of death, were increased in the acute kidney injury group (hazard ratio [HR], 5.7 [95% confidence interval, 3.8-8.7] and HR, 1.9 [95% confidence interval, 1.3-2.8], respectively). The addition of serum cystatin C increased the ability to predict the risk of developing CKD stage 3, and death (HR, 1.5 [1.1-2.0] and 1.6 [1.1-2.3], respectively). The addition of plasma NGAL resulted in no improvement in predicting CKD stage 3 or mortality (HR, 1.0 [0.7-1.5] and 1.2 [0.8-1.8], respectively). The risk of developing CKD stage 3 was also significantly increased in the transient azotemia group (HR, 2.4 [1.5-3.6]). Thus, an episode of community acquired acute kidney injury markedly increases the risk of CKD, and moderately increases the risk of death. Our findings highlight the importance of follow-up of patients with community acquired acute kidney injury, for potential early initiation of renal protective strategies.

Mapping atmospheric pollutants emissions in European countries

In this paper we present a methodology which enables the graphical representation, in a bi-dimensional Euclidean space, of atmospheric pollutants emissions in European countries. This approach relies on the use of Multidimensional Unfolding MDU, an exploratory multivariate data analysis technique. This technique illustrates both the relationships between the emitted gases and the gases and their geographical origins. The main contribution of this work concerns the evaluation of MDU solutions. We use simulated data to define thresholds for the model fitting measures, allowing the MDU output quality evaluation. The quality assessment of the model adjustment is thus carried out as a step before interpretation of the gas types and geographical origins results. The MDU maps analysis generates useful insights, with an immediate substantive result and enables the formulation of hypotheses for further analysis and modeling.