IntroductionUnlike the general population, a higher body mass index (BMI) is associated with greater survival among patients with chronic kidney disease (CKD). This “obesity paradox” may be due to limitations of BMI as a measure of adiposity in CKD. Both BMI and body fat percentage (BF%) are used to classify obesity, but outcomes may vary. Therefore, we investigated the 2 different cutoffs for diagnosing obesity (BMI ≥28 kg/m2 or BF% >25% for men and >35% for women) and the impact on all-cause mortality in CKD.MethodsA total of 326 patients with non–dialysis-dependent CKD were prospectively followed for a median of 4.9 years (range 2.9–5.3). BF% and lean body mass were determined using the Body Composition Monitor, a novel multifrequency bioimpedance spectroscopy device. Covariates included age, gender, diabetes, cardiovascular disease, estimated glomerular filtration rate, proteinuria, and high-sensitivity C-reactive protein.ResultsPer the BMI definition, 27.9% of patients were obese. However, 48.8% of patients were obese according to the BF% definition. A BMI ≥28 kg/m2 had a moderately high specificity of 83.2% but a low sensitivity of 39.6% for detecting BF%-defined obesity. In the fully adjusted models containing both BMI and BF%, obesity defined by BMI was associated with a significantly lower risk of death (hazard ratio [HR]: 0.23; 95% CI: 0.07–0.71; P = 0.011), whereas the result was reversed when obesity was defined by BF% (HR: 2.75; 95% CI: 1.28–5.89; P = 0.009). When patients were classified into 4 distinct groups based on both the BMI and BF% cutoffs for obesity, a considerable proportion of patients (29.4%) had excess body fat in the context of a normal BMI. These patients were more likely to have lower lean body mass (i.e., sarcopenic obesity) and had higher mortality compared with patients with obesity defined by both BMI and BF% (HR: 5.11; 95% CI: 1.43–18.26; P = 0.012).ConclusionDiagnostic discordance between BMI and BF% may partly explain the obesity paradox. Proper diagnosis of obesity in patients with CKD is required for both risk prediction and treatment.

BackgroundThe Taiwan Health Insurance Bureau has conducted a bundled payment system for hemodialysis reimbursement since 1995. The maximum dose of erythropoiesis‐stimulating agents allowed by insurance is capped at 20 000 U of epoetin or 100 μg of darbepoetin alfa per month. Nephrologists have avoided the use of high dosages of erythropoiesis‐stimulating agents to achieve a hemoglobin level of 10 to 11 g/dL by iron supplementation. The clinical impact of these policies on patients’ outcomes is unknown. The authors aimed to assess the AIM‐HD (Association of Anemia, Iron parameters, and Mortality among the prevalent Hemodialysis patients) Study in Taiwan.Methods and ResultsThe AIM‐HD study was conducted based on the Taiwan Renal Registry Data System. From 2001 to 2008, the authors enrolled 42 230 patients undergoing hemodialysis who were older than 20 years and had received hemodialysis for more than 12 months. Patient follow‐ups occurred until death or December 31, 2008. During a study period of 8 years, 12 653 (30.0%) patients died. After multivariate adjustment, the authors found that a hemoglobin level <10 g/dL was significantly associated with higher risk for all‐cause and cardiovascular deaths. Moreover, a serum ferritin level between 300 and 800 ng/mL and transferrin saturation value between 30% and 50% were associated with the lowest all‐cause mortality.ConclusionsThe authors recommend avoiding a low hemoglobin level and maintaining serum ferritin between 300 and 800 ng/mL and transferrin saturation between 30% and 50%, which were associated with lower risks of all‐cause mortality among patients undergoing hemodialysis receiving the restricted erythropoiesis‐stimulating agent doses but prompt intravenous iron supplementation in Taiwan.

BackgroundThe benefit of alpha-Ketoanalogues (KA) supplementation for chronic kidney disease (CKD) patients that followed low-protein diet (LPD) remains undetermined.MethodsWe extracted longitudinal data for all CKD patients in the Taiwan National Health Insurance from January 1, 2000 through December 31, 2010. A total of 1483 patients with anemic advanced CKD treated with LPD, who started KA supplementation, were enrolled in this study. We analyzed the risks of end stage renal disease and all-cause mortality using Cox proportional hazard models with influential drugs as time-dependent variables.ResultsA total of 1113 events of initiating long-term dialysis and 1228 events of the composite outcome of long-term dialysis or death occurred in patients with advanced CKD after a mean follow-up of 1.57 years. Data analysis suggests KA supplementation is associated with a lower risk for long-term dialysis and the composite outcome when daily dosage is more than 5.5 tablets. The beneficial effect was consistent in subgroup analysis, independent of age, sex, and comorbidities.ConclusionsAmong advanced CKD patients that followed LPD, KA supplementation at an appropriate dosage may substantially reduce the risk of initiating long-term dialysis or of developing the composite outcome. KA supplementation represents an additional therapeutic strategy to slow the progression of CKD.