Tip Lesion Variant of Focal and Segmental Glomerulosclerosis in a COVID-19 Patient

Acute kidney injury is a common complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Several pathologic findings are continually being reported, showing a probably multifactorial etiology. The authors present a case of a patient diagnosed with a tip lesion variant of focal segmental glomerulosclerosis (FSGS) in the setting of COVID-19. A 43-year-old African American female with no known renal disease presented to the emergency department with a 6-day history of fatigue, headache, hypoageusia, myalgia, cough, nausea, and vomiting. Laboratory tests confirmed SARS-CoV-2 infection. During hospitalization, there was a progressive decline in kidney function and evidence of nephrotic-range proteinuria without nephrotic syndrome. Biopsy specimen showed a tip lesion variant of FSGS. Genetic test revealed a homozygous variant of uncertain clinical significance (c.397G>A [p.V133M]) in the epithelial membrane protein 2 (EMP2) gene. To our knowledge, this is the first case report of a tip lesion in a COVID-19 patient with no renal history. More studies are warranted to define susceptible groups and identify the detailed mechanisms of COVID-19-related kidney disease that would allow for specific management of this complication.

The Usefulness of Calcium/Magnesium Ratio in the Risk Stratification of Early Onset of Renal Replacement Therapy

Background: A growing number of studies have reported a close relationship between high serum calcium (Ca)/low serum magnesium (Mg) and vascular calcification. Endothelial dysfunction and vascular inflammation seem plausible risk factors for the enhanced progression of kidney disease. The aim of this study was to evaluate the role of the Ca/Mg ratio as a predictor of the early onset of renal replacement therapy (RRT). Methods: This was a prospective study conducted in an outpatient low-clearance nephrology clinic, enrolling 693 patients with stages 4−5 of CKD. Patients were divided into two groups according to the start of renal replacement therapy (RRT). Results: The kidney’s survival at 120 months was 60% for a Ca−Mg ratio < 6 and 40% for a Ca−Mg ratio ≥ 6 (p = 0.000). Patients who started RRT had lower levels of Hb, Ca, Mg, albumin, and cholesterol and higher values of phosphorus, the Ca/Mg ratio, and PTH. High values of phosphorus and the Ca/Mg ratio and low levels of Mg and GFR were independent predictors of entry into RRT. A high Ca/Mg ratio, high phosphorus levels, and low levels of GFR were associated with a cumulative risk for initiation of RRT. Conclusions: In our population, the Ca/Mg ratio is an independent predictive factor for the initiation of a depurative technique.

MO695: Phase Angle: Clinical and Prognostic Value in Peritoneal Dialysis

BACKGROUND AND AIMS

Malnutrition–inflammation–atherosclerosis syndrome is common in chronic kidney disease and is associated with high mortality, particularly in dialysis patients. Bioimpedance analysis (BIA) is a simple and non-invasive method for nutritional assessment. The aim of this study was to evaluate the relationship between phase angle (PA) and other nutritional parameters and establish its role as predictor of mortality in peritoneal dialysis (PD) patients.

METHOD

Prevalent PD patients were enrolled in the longitudinal prospective study in a single tertiary center between 2015 and 2020, with a simultaneous BIA assessment and a modified peritoneal equilibration test. Spearman's correlation test was used to assess relevant clinical associations. Survival analysis was performed using the Kaplan–Meier test and univariate and multivariate Cox analysis to determine the predictive factors of all-cause mortality.

RESULTS

A total of 49 PD patients were included with mean age 55.9 ± 16.2 years, 57.1% male, Charlson comorbidity index 4.9 ± 2.3, Kt/V 2.5 ± 0.7, with a mean follow-up of 39.9 ± 26.3 months. The Spearman's correlation test showed a very strong positive association between PA and extracellular mass/body cell mass (r = 0.939, P &lt; 0.001). It also showed a moderate positive association between PA and albumin (r = 0.524, P &lt; 0.001) and normalized protein catabolism rate (r = 0.437, P = 0.002). Furthermore, PA was negatively correlated with age (r = −0.477, P = 0.001). In the Kaplan–Meier analysis, patients with PA &lt; 4.9° had a lower survival rate (log rank = 4.77; P = 0.029). Using the multivariate Cox regression, forward model, PA (HR = 0.243; 95% CI 0.079–0.753), the number of cardiovascular events (HR = 11.236; 95% CI 1.286–98.211) and neutrophil–lymphocyte ratio (HR = 1.360; 95% CI 1.033–1.790) were predictors of all-cause mortality.

CONCLUSION

Lower PA appears to be associated with a decline in nutritional status, so monitoring it can be useful to identify patients at higher risk of malnutrition. PA was also validated as an independent predictor of mortality in our PD patients.

MO451: The Usefulness of Calcium/Magnesium Ratio in the Risk Stratification of Early Onset of Renal Replacement Therapy

BACKGROUND AND AIMS

Recently, a growing number of studies have reported a close relationship between high serum calcium and low serum magnesium with vascular calcification. Endothelial dysfunction and vascular inflammation seem plausible risk factors for enhanced progression of kidney disease nevertheless, the knowledge remains scarce. The aim of this study is to evaluate the role of the calcium/magnesium ratio as a risk factor in CKD progression.

METHOD

Observational, prospective study involving 693 patients (f = 371, m = 322) with stage 4 and 5 CKD. Patients were divided into two groups, according to the development of end-stage renal disease (ESRD): G1 (n = 541), who did not undergo renal replacement therapy and G2 (n = 152), who had started renal replacement therapy (RRT). Several laboratory parameters were measured: haemoglobin, eGFR (MDRD), albumin, cholesterol, magnesium and mineral metabolism markers (PTH, calcium and phosphorus). Baseline characteristics were analysed and compared using Student%u2019s T-test for continuous variables and chi-squared test for categorical variables. Multivariate Cox regression analysis was used to identify independent factors associated with RRT initiation. A modified Poisson regression with robust error variance was used to estimate the cumulative relative risk for RRT initiation.

RESULTS

The mean age and estimated glomerular filtration rate (eGFR) of the study population was 70.09 ± 12.51 years and 19.91 ± 8.11 mL/min, respectively. Comparing the two groups, G2 had a significantly lower serum levels of Hb (11.75 versus 10.95 g/dL, P = 0.000), calcium (9.34 versus 8.95 mg/dL, P = 0.000), magnesium (1.92 versus 1.40 mg/dL, P = 0.0001), albumin (4.00 versus 3.88 g/dL, P = 0.03) and cholesterol (183.17 versus 172.39 mg/dL, P = 0.01) and a higher serum levels of phosphorus (3.88 versus 4.69 mg/dL, P = 0.0001), calcium/magnesium ratio (5.73 versus 7.56, P = 0.0001) and PTH (209.71 versus 338.84 pg/mL, P = 0.0001). In univariate Cox regression analysis, age, haemoglobin, eGFR, calcium, magnesium, phosphorus, calcium-magnesium ratio and PTH correlate with onset of RRT, which were further tested using a multivariate COX regression model. The results showed a clear relationship between high levels of phosphorus (HRa = 1.638, P = 0.001) and calcium-magnesium ratio (HRa = 1.292; P = 0.002), and low levels of magnesium (HRa = 0.761, P = 0.005) and eGFR (HRa = 0.934; P = 0.0001) were independent risk factors to start depurative techniques. Additionally, Poisson regression analysis showed that high calcium-magnesium ratios (aPR = 1.986; 95% CI 1.026–3.051; P = 0.002), high phosphorus levels (aPR = 1.607; 95% CI 1.324–1.950; P &lt; 0.0001) and low levels eGFR (aPR = 0.927; 95% CI 0.891–0.964; P &lt; 0.0001) were associated with a cumulative risk for initiation of RRT.

CONCLUSION

Our results suggest that the calcium/magnesium ratio is an independent predictive factor for the initiation of renal replacement therapy. Further studies are required to validate the use of this novel marker as a predictor of CKD progression.

MO754: Impact of Calcium-to-Magnesium Ratio on Carotid Intima-Media ThicknessCardiovascular Risk Assessment in Haemodialysis

BACKGROUND AND AIMS

Cardiovascular disease (CVD) is the leading cause of death in chronic kidney disease patients. The interaction between calcium and magnesium has been associated with several pathophysiological processes that occur in the vessel wall, such as endothelial dysfunction and vascular calcification. The aim of this study was to assess the relationship between calcium-to-magnesium (Ca: Mg) ratio and carotid intima-media thickness (CIMT), a widely used risk marker for CVD in the assessment of subclinical atherosclerosis. This study also aimed to establish the role of the Ca: Mg ratio as a predictor of cardiovascular mortality in haemodialysis (HD).

METHOD

Prevalent HD patients were enrolled in the longitudinal prospective study in a single tertiary centre. According to CIMT measured through B-mode ultrasound, the patients were divided into two groups: ≥0.9 mm (G1) and &lt;0.9 mm (G2). Data from both groups were compared by Student's t-test. Partial correlation was used to assess the relationship between the variables under analysis and the CIMT, when controlled by dialysis time. The prevalence ratio of predictors of carotid thickening was calculated using a Poisson model with robust variance. Multivariable Cox regression analysis was performed to determine the predictive factors of cardiovascular death.

RESULTS

A total of 120 patients on HD were included with mean age 66.5 ± 13.97 years, 66.7% male. Magnesium (P &lt; 0.001), Ca: Mg ratio (P &lt; 0.001) and Adragão score (P &lt;0.001) were statistically different between the two groups (Table 1). The partial correlation showed a strong positive association between CIMT and Ca: Mg ratio (r = 0.873; P &lt;0.001) and a moderate association between CIMT and Adragão score (r = 0.614, P &lt; 0.001), whereas there was a moderate negative correlation between CIMT and magnesium (r = –0.671, P &lt;0.001). The Poisson model showed high prevalence of carotid thickening for higher values ​​of Ca: Mg ratio [aPR = 1.055, 95% confidence interval (95% Cl) 1.007–2.176] and Adragão score (aPR = 1.106, 95% Cl 1.006–1.351), and for lower magnesium values ​​(aPR = 0.462, 95% CI 0.248–0.861). Using the multivariate Cox model, age (HR = 1.045, 95% CI 1.012–1.084), Adragão score (HR = 1.078, 95% CI 1.006–1.234) and Ca: Mg ratio (HR = 1.154, 95% CI 1.098–2.236) were predictors of cardiovascular mortality.

CONCLUSION

In our population, the Ca: Mg ratio was a predictor of carotid thickening, so its monitoring can be useful to identify patients at higher cardiovascular risk. The Ca: Mg ratio was further validated as a predictor of cardiovascular mortality in HD patients. More studies are needed to better understand the relationship between this ratio and cardiovascular events.