Fernanda C. Amparo

Sarcopenia in chronic kidney disease on conservative therapy: prevalence and association with mortality

BACKGROUND In chronic kidney disease (CKD), multiple metabolic and nutritional abnormalities contribute to the impairment of skeletal muscle mass and function thus predisposing patients to the condition of sarcopenia. Herein, we investigated the prevalence and mortality predictive power of sarcopenia, defined by three different methods, in non-dialysis-dependent (NDD) CKD patients. METHODS We evaluated 287 NDD-CKD patients in stages 3-5 [59.9 ± 10.5 years; 62% men; 49% diabetics; glomerular filtration rate (GFR) 25.0 ± 15.8 mL/min/1.73 m(2)]. Sarcopenia was defined as reduced muscle function assessed by handgrip strength (HGS <30th percentile of a population-based reference adjusted for sex and age) plus diminished muscle mass assessed by three different methods: (i) midarm muscle circumference (MAMC) <90% of reference value (A), (ii) muscle wasting by subjective global assessment (B) and (iii) reduced skeletal muscle mass index (<10.76 kg/m² men; <6.76 kg/m² women) estimated by bioelectrical impedance analysis (BIA) (C). Patients were followed for up to 40 months for all-cause mortality, and there was no loss of follow-up. RESULTS The prevalence of sarcopenia was 9.8% (A), 9.4% (B) and 5.9% (C). The kappa agreement between the methods were 0.69 (A versus B), 0.49 (A versus C) and 0.46 (B versus C). During follow-up, 51 patients (18%) died, and the frequency of sarcopenia was significantly higher among non-survivors. In crude Cox analysis, sarcopenia diagnosed by the three methods was associated with a higher hazard for mortality; however, only sarcopenia diagnosed by method C remained as a predictor of mortality after multivariate adjustment. CONCLUSIONS The prevalence of sarcopenia in CKD patients on conservative therapy varies according to the method applied. Sarcopenia defined as reduced handgrip strength and low skeletal muscle mass index estimated by BIA was an independent predictor of mortality in these patients.

Visceral fat and coronary artery calcification in patients with chronic kidney disease

BACKGROUND Abdominal fat is a metabolically active tissue which has been associated with cardiovascular events and death in chronic kidney disease (CKD) patients. We explore here the association between surrogates of abdominal fat and coronary artery calcium score (CACs). METHODS Cross-sectional analysis of 232 non-dialysis-dependent CKD patients Stages 3-5 (median age 60 [25th-75th percentile 52-67] years; 60% men). Visceral adipose tissue (VAT) and CACs were assessed by computed tomography. Surrogates of abdominal fat included VAT and waist circumference (WC). RESULTS VAT was positively associated with CACs in univariate analysis (ρ = 0.23). Across increasing VAT quartiles, patients were older, more often men and smokers. Although increasing VAT quartiles associated with higher glomerular filtration rate and leptin, better nutritional status (subjective global assessment) as well as larger muscle stores and strength, they were also more insulin resistant (HOMA-IR), dyslipidemic and inflamed (C-reactive protein and white blood cells). In addition, CACs were incrementally higher. Clinically evident coronary artery calcification (CACs ≥ 10 Agatston) was present in 63% of the patients. Both increased visceral fat (odd ratio 1.60 [95% CI 1.23-2.09] per standard deviation increase) and increased WC (1.05 [1.01-1.12] per cm increase), augmented the odds to present calcification. Such associations remained statistically significant after extensive multivariate adjustment for confounders. CONCLUSIONS Abdominal fat is associated with coronary artery calcification in non-dialysis dependent CKD patients, supporting its potential role as a cardiovascular risk factor in uremia.

Diagnostic validation and prognostic significance of the Malnutrition-Inflammation Score in nondialyzed chronic kidney disease patients.

BACKGROUND Malnutrition and inflammation are highly prevalent and intimately linked conditions in chronic kidney disease (CKD) patients that lead to a state of protein-energy wasting (PEW), the severity of which can be assessed by the Malnutrition-Inflammation Score (MIS). Here, we applied MIS and validated, for the first time, its ability to grade PEW and predict mortality in nondialyzed CKD patients. METHODS We cross-sectionally evaluated 300 CKD stages 3-5 patients [median age 61 (53-68) years; estimated glomerular filtration rate 18 (12-27) mL/min/1.73 m(2); 63% men] referred for the first time to our center. Patients were followed during a median 30 (18-37) months for all-cause mortality. RESULTS A worsening in MIS scale was associated with inflammatory biomarkers increase (i.e. alpha-1 acid glycoprotein, fibrinogen, ferritin and C-reactive protein) as well as a progressive deterioration in various MIS-independent indicators of nutritional status based on anthropometrics, dynamometry, urea kinetics and bioelectric impedance analysis. A structural equation model with two latent variables (assessing simultaneously malnutrition and inflammation factors) demonstrated good fit to the observed data. During a follow-up, 71 deaths were recorded; patients with higher MIS were at increased mortality risk in both crude and adjusted Cox models. CONCLUSIONS MIS appears to be a useful tool to assess PEW in nondialyzed CKD patients. In addition, MIS identified patients at increased mortality risk.

Malnutrition-Inflammation Score is Associated With Handgrip Strength in Nondialysis-Dependent Chronic Kidney Disease Patients

OBJECTIVE The malnutrition-inflammation score (MIS) is a nutritional scoring system that has been associated with muscle strength among dialysis patients. We aimed to test whether MIS is able to predict muscle strength in nondialysis-dependent chronic kidney disease (NDD-CKD) individuals. DESIGN AND METHODS This was a cross-sectional study conducted at the Dante Pazzanese Institute of Cardiology, Hypertension, and Nephrology Division outpatient clinic. We evaluated 190 patients with NDD-CKD stages 2-5 (median 59.5 [interquartile range 51.4-66.9] years; 64% men). MIS was calculated without computing dialysis vintage to the scoring. HGS was assessed in the dominant arm. Anthropometric, laboratory, and body composition parameters were recorded. RESULTS A strong negative correlation was found between HGS and MIS (r = -0.42; P ≤ .001) in univariate analysis. In multivariate regressions, adjustment for age, sex, diabetes, glomerular filtration rate, body cell mass, and C-reactive protein did not materially diminish these relationships. CONCLUSIONS MIS shares strong links with objective measures of muscle strength in NDD-CKD patients.

Reliability of electrocardiographic surrogates of left ventricular mass in patients with chronic kidney disease.

Objective: Left ventricular hypertrophy (LVH) is a prevalent condition in chronic kidney disease (CKD) very often underdiagnosed and misdiagnosed. Electrocardiography (ECG) is an easily accessible LVH diagnostic tool. We evaluated the usefulness of commonly applied ECG criteria for LVH diagnosis in CKD patients. Methods: Cross-sectional evaluation of 253 nondialysis-dependent CKD stages 3–5 patients (61 [53–67] years; 65% men). Left ventricular mass (LVM) was assessed by echocardiography (ECHO). ECG was performed to assess Cornell voltage and Sokolow–Lyon voltage and their products (Cornell product and Sokolow–Lyon product, respectively). Results: The prevalence of LVH ranged from 72 to 89% depending on ECHO criteria used. Cornell product showed the best correlation with ECHO-estimated LVM (&rgr; = 0.41; P <0.001). Across sex-specific tertiles of ECHO-LVM, ECG criteria increased and patients were more often hypertensive, obese, fluid overloaded, inflamed, and with higher albuminuria. Cornell product showed the strongest association with ECHO-LVM in crude and adjusted regression models, and the higher predictive performance for all the ECHO-based LVH definitions. However, when applying literature-based ECG cut-offs for LVH diagnosis, Sokolow–Lyon product showed a higher specificity. The agreement between ECG criteria cut-offs and ECHO-based definitions of LVH was in general poor, and the number of patients reclassified correctly by ECHO ranged from 77 to 94%. Conclusion: Our data suggest that ECG alone is a weak indicator of LVH, and do not support its routine use as a unique tool in the screening of LVH in CKD patients. Further studies are needed to confirm these results and to try establishing adequate cut-offs for LVH diagnosis in this population.