The association between salt intake and renal outcome in subjects with preserved kidney function remains unclear. Here we evaluated the effect of sodium intake on the development of chronic kidney disease (CKD) in a prospective cohort of people with normal renal function. Data were obtained from the Korean Genome and Epidemiology Study, a prospective community-based cohort study while sodium intake was estimated by a 24-hour dietary recall Food Frequency Questionnaire. A total of 3,106 individuals with and 4,871 patients without hypertension were analyzed with a primary end point of CKD development [a composite of estimated glomerular filtration rate (eGFR) under 60 mL/min/1.73 m and/or development of proteinuria during follow-up]. The median ages were 55 and 47 years, the proportions of males 50.9% and 46.3%, and the median eGFR 92 and 96 mL/min/1.73 m in individuals with and without hypertension, respectively. During a median follow-up of 123 months in individuals with hypertension and 140 months in those without hypertension, CKD developed in 27.8% and 16.5%, respectively. After adjusting for confounders, multiple Cox models indicated that the risk of CKD development was significantly higher in people with hypertension who consumed less than 2.08 g/day or over 4.03 g/day sodium than in those who consumed between 2.93-4.03 g/day sodium. However, there was no significant difference in the incident CKD risk among each quartile of people without hypertension. Thus, both high and low sodium intakes were associated with increased risk for CKD, but this relationship was only observed in people with hypertension.

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Fibroblast growth factor-23 (FGF23) is an established biomarker of adverse outcomes in patients with chronic kidney disease (CKD). Several cross-sectional studies have suggested a possible association between FGF23 and anemia in these patients. In this large-scale prospective cohort study, we investigated this relationship and examined whether high FGF23 levels increase the risk of incident anemia. This prospective longitudinal study included 2,089 patients from the KoreaN cohort study for Outcome in patients With CKD. Anemia was defined as hemoglobin level <13.0 g/dl (men) and <12.0 g/dl (women). Log-transformed FGF23 significantly correlated with hepcidin but inversely correlated with iron profiles and hemoglobin. Multivariate logistic regression showed that log-transformed FGF23 was independently associated with anemia (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.04–1.24, P = 0.01). Among 1,164 patients without anemia at baseline, 295 (25.3%) developed anemia during a median follow-up of 21 months. In fully adjusted multivariable Cox models, the risk of anemia development was significantly higher in the third (hazard ratio [HR], 1.66; 95% CI, 1.11–2.47; P = 0.01) and fourth (HR, 1.84; 95% CI, 1.23–2.76; P = 0.001) than in the first FGF23 quartile. In conclusion, high serum FGF23 levels were associated with an increased risk for anemia in patients with nondialysis CKD.

BackgroundMany epidemiologic studies have reported on the controversial concept of the obesity paradox. The presence of acute kidney injury (AKI) can accelerate energy-consuming processes, particularly in patients requiring continuous renal replacement therapy (CRRT). Thus, we aimed to investigate whether obesity can provide a survival benefit in this highly catabolic condition.MethodsWe conducted an observational study in 212 patients who had undergone CRRT owing to various causes of AKI between 2010 and 2014. The study end point was defined as death that occurred within 30 days after the initiation of CRRT.ResultsPatients were categorized into three groups according to tertiles of body mass index (BMI). During ≥30 days after the initiation of CRRT, 39 patients (57.4%) in the highest tertile died, as compared with 58 patients (78.4%) in the lowest tertile (P = 0.02). In a multivariable analysis adjusted for cofounding factors, the highest tertile of BMI was significantly associated with a decreased risk of death (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.37–0.87; P = 0.01). This significant association remained unaltered for 60-day (HR, 0.64; 95% CI, 0.43–0.94; P = 0.03) and 90-day mortality (HR, 0.66; 95% CI, 0.44–0.97; P = 0.03).ConclusionThis study showed that a higher BMI confer a survival benefit over a lower BMI in AKI patients undergoing CRRT.

Depression and suicidal ideation are prevalent mental health problems in patients with chronic kidney disease (CKD. However, the association between mental health problems and kidney disease has been investigated in severe cases only. Thus, this study evaluated the relationship between mental health problems and renal function in a community-based prospective cohort study comprising patients with mild to moderate kidney disease. A total of 44,938 participants who were participated in Korean National Health and Nutrition Examination Survey IV, V, and VI from 2007 to 2014 were enrolled. Estimated glomerular filtration rate (eGFR) was calculated using the CKD Epidemiology Collaboration equation. The study outcome was the prevalence of depression and suicidal ideations assessed by self-reporting surveys. Logistic regression analysis was performed to evaluate the relationship between renal function and outcomes. The mean age of the study subjects was 49.2 ± 16.6 years, and the mean eGFR was 94.0 mL/min/1.73 m2. The prevalence of depression and suicidal ideation increased with decreasing eGFR. Multivariate logistic regression analysis showed that the risk of depression increased in subjects with eGFR <45 mL/min/1.73 m2 [odds ratio (OR) 1.47; 95% confidence interval (CI) 1.09–1.98]. The risk of suicidal ideation gradually increased in groups with eGFR <90 mL/min/1.73 m2 (OR, 1.11; 95% CI, 1.03–1.20), even after adjustments for confounding variables. In conclusion, depression and suicidal ideation are related closely with renal dysfunction. The risk of having depression and suicidal ideation increased even in patient with mild renal dysfunction. Therefore, evaluation and management strategies regarding mental health problems should be taken into account throughout all stages of CKD.