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Background and Aims Low physical performance in patients undergoing maintenance hemodialysis is associated with a high mortality rate. We investigated the clinical relevance of gait speed and handgrip strength, the two most commonly used methods to assess physical performance. Method We obtained data regarding gait speed and handgrip strength from 277 hemodialysis patients and evaluated their relationship with baseline parameters, mental health, plasma inflammatory markers, and major adverse clinical outcomes. Low physical performance was defined by the recommendations suggested by the Asian Working Group on Sarcopenia. Results The prevalence of low gait speed and handgrip strength were 28.2% and 44.8%, respectively. Old age, low serum albumin levels, high comorbidity index, and impaired cognitive functions were associated with low physical performance. Patients with isolated low gait speed exhibited a general trend for worse quality of life than those with isolated low handgrip strength. Gait speed and handgrip strength showed very weak correlations with had different determinant factors (older age, the presence of diabetes, and lower serum albumin for low gait speed, and lower body mass index, and the presence of previous cardiovascular events for low handgrip strength). Patients with low gait speed and handgrip strength had elevated levels of plasma endocan and matrix metalloproteinase-7 and the highest risk of all-cause mortality and cardiovascular events among the groups (adjusted hazard ratio of 2.72, p = 0.024). Conclusion Gait speed and handgrip strength reflected distinctive aspects of patient characteristics and that their combination improved the prediction of adverse clinical outcomes in hemodialysis patients. Gait speed seems to be a better indicator for poor patient outcomes compared with handgrip strength.

Background and Aims A recent study demonstrated female rats more rapidly excreted urine sodium and water under saline bolus infusion than male rats, and suggested sexual dimorphisms in renal transporters. However, the sexual differences in renal salt and water excretion was not yet investigated with human data. We purposed to clarify whether the sexual difference of natriuretic and diuretic ability exists, and it contributes to decreasing blood pressure (BP) in nondiabetic chronic kidney disease (CKD) patients. Method This is a secondary analysis of an open-label, randomized, controlled study determining the effect of intensive low-salt diet education on BP and albuminuria in nondiabetic CKD patients. A total of 235 patients had stopped all renin-angiotensin blocking agents or diuretics during a run-in period for eight weeks (0w). After the run-in period, they received olmesartan (40mg daily) for eight weeks (8w), and then maintained the same medicine with low-salt diet education for an additional eight weeks (16w). Results Mean age of premenopausal women (n=50), same-aged young men (n=76), postmenopausal women (n=68), and same-aged older men (n=41) was 40.7, 40.2, 59.0, and 69.9 years old, respectively. Their MDRD eGFR was 76.2, 71.6, 59.8, and 58.8 mL/min/1.73m2, respectively. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) was lower in premenopausal women (129/79 mmHg) than in young men (134/83 mmHg). Daily salt intake decreased in 16w in premenopausal women (1839 → 1288mg, p=0.008) and young men (2494 → 1552mg, p=0.001) compared with them in 0w, while there was no significant change in postmenopausal women (2443 → 2171mg, p=0.610) and older men (2870 → 2366mg, p=0.458). Except for the premenopausal women (136 (0w) → 133 (16w) mEq/day, p=0.749), urine sodium excretion for 24 hours significantly decreased in 16w compared with that in 0w or 8w (young men: 154 (8w) → 137 (16w)mEq/day p=0.042, postmenopausal women: 152 (0w) → 128m (16w)Eq/day p=0.016, older men: 181 (0w) → 145 (16w)mEq/day p=0.019). Also, urine volume was significantly larger in the premenopausal women than in young men in 8w and 16w (8w: 1009 vs. 980mL p=0.002, 16w: 1004 vs. 978mL, p=0.006), while it was not different between postmenopausal women and older men (8w: 1002 vs. 990 p=0.347, 16w: 1003 vs. 1001 p=0.895). The urine volume was positively correlated with BP in the premenopausal women, while it was negatively associated with BP in young men in 16w. Conclusion Although sodium intake was similarly decreased in premenopausal women and young men, urine sodium excretion did not fall, and urine volume increased in premenopausal women. This phenomenon disappeared in postmenopausal women. Augmented natriuretic and diuretic potency might contribute to lower BP in premenopausal women with nondiabetic CKD.

Background and Aims Although obesity is a well-known risk factor for chronic kidney disease (CKD), previous epidemiologic studies have produced mixed results. This study was purposed to investigate the relationship between obesity and CKD occurrence in the healthy middle-aged Korean population. Method We used a prospective, longitudinal data from the Korean Genome and Epidemiology Study (KoGES), a population-based, epidemiology study in South Korea (2001-2014). A total of 6,678 participants aged 40-69 who were free of diabetes, hypertension, and CKD at baseline were followed-up biennially. CKD was defined as at least two-time occurrence of estimated glomerular filtration rate < 60 mL/min/1.73m2 using CKD-EPI equation during the follow-up period. Results A total of 433 participants (6.5%) developed CKD. We divided the participants into 5 groups by BMI: underweight (BMI < 18.5), normal-weight (BMI 18.5-22.0), overweight 1 (BMI 23.0-24.9), overweight 2 (BMD 25-29.9), and obesity (BMI >30). Compared to the normal-weight group, hazard ratio of CKD occurrence was elevated in overweight 2 (HR=1.43, p=0.01) and obesity (HR=1.73, p=0.03) in multivariate-adjusted regression analysis (variates: age, newly developed hypertension, newly developed diabetes, fasting glucose > 126mg/dL, 2hours glucose > 200mg/dL, systolic blood pressure > 140mmHg, physical activity, alcohol consumption, smoking). When dividing the participants into three age groups: the 40s, 50s, and 60s, only the 60s group showed a significant correlation of BMI with CKD occurrence (overweight 2: HR=1.93, p=0.05, obesity: HR=3.94, p=0.03). Conclusion The risk of CKD was significantly high for those in their 60s who were overweight or obese despite free of underlying diseases in the Korean population.

Background and Aims Cognitive impairment is common in older adults. Similarly, the prevalence of renal dysfunction is also increased in the elderly. We conducted this study to clarify the relationship between the renal function and cognitive impairment in community dwelling older adults in Korea. Method A cross-sectional analysis was performed on the data of the Korean Frailty and Aging Cohort Study (KFACS), a nationwide cohort study that began in 2016. Of the 3014 participants assessed in the first and second year, 2847 participants (1333 men, 1514 women) who completed baseline assessments were enrolled. The estimated glomerular filtration rate (eGFR, mL/min/1.73m2) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Renal function of the participants was classified into four groups by eGFR quartile. General cognitive function was accessed with mini-mental state exam in the Korean version (MMSE-KC). Participants who had MMSE-KC score less than 1.5 standard deviation by age, gender, and education level were regarded as the cognitive impairment. Multivariate logistic regression model was used to examine the relationship between renal function and cognitive impairment. In addition, we investigated to find the point of eGFR interval at which the odds ratio begins to increase. Results The mean eGFR in quartile 1 was 91.7 ± 3.22 ml/min/1.73m2, and 84.9 ± 1.81 in quartile 2, 76.1 ± 3.66 in quartile 3, and 57.2 ± 10.75 in quartile 4. In baseline characteristics, participants with lower eGFR had lower MMSE-KC scores. And the prevalence of cognitive impairment was 10.8% in quartile 1, 15.9% in quartile 2, 15.2% in quartile 3, 14.9% in quartile 4. After multivariate adjustment, the odds ratio (OR) of cognitive impairment in quartile 2 [adjusted OR: 1.569, 95% confidence intervals (CI): 1.141 - 2.158, p = 0.006] compared with quartile 1. And the odd ratios of cognitive impairment were 1.539 (95% CI: 1.113 - 2.127, p = 0.009) in quartile 3, 1.475 (95% CI: 1.062 - 2.049, p = 0.020) in quartile 4 compared with quartile 1, respectively. Among the participants with eGFR above 60 ml/min/1.73m2, the renal function was grouped by 5 ml/min/1.73m2 interval. The risk of cognitive impairment started to increase from eGFR between 80 and 85 ml/min/1.73m2 (adjusted OR: 1.667, 95% CI: 1.128 - 2.463, p = 0.010). Conclusion Renal dysfunction was associated with lower global cognitive function in older adults. And the risk of cognitive impairment increased from quartile 2, especially, eGFR between 80 and 85 ml/min/1.73m2 in this population. These results suggest that mild decline of kidney function is also a risk factor of cognitive decline in the elderly.

Background and Aims Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a promising new target for prevention of cardiovascular (CV) events. However, the clinical significance of circulating PCSK9 is unclear in hemodialysis (HD) patients. Method A total of 353 HD patients were prospectively enrolled from June 2016 to May 2018 in a K-cohort. Plasma PCSK9 level was measured at the time of study enrollment. Patients were classified into three groups based on PCSK9 tertile. The primary endpoint was defined as composite of CV event and death from any cause. Results Plasma PCSK9 level was positively correlated with total cholesterol level in patients with statin treatment. However, PCSK9 was not related to plasma inflammatory (high-sensitivity C-reactive peptide, monocyte chemoattractant protein-1, interleukin-6) or calcification-related markers (osteoprotegerin and receptor activator of nuclear factor kappa-Β ligand). Multivariate linear regression analysis revealed that baseline statin treatment and serum glucose, albumin, and total cholesterol were independent determinants of circulating PCSK9 levels. In Cox-regression analysis, PCSK9 tertile 3 was associated with a 1.99-fold risk for composite events (95% CI, 1.08–3.66), and it was associated with a 2.26-fold risk for CV events (95% CI, 1.11–4.62) after adjustment for multiple variables. PCSK9 tertile 3 provides additional prognostic power to predict composite events in subgroups with higher levels of high-sensitivity C-reactive peptide and LDL. Conclusion In conclusion, higher circulating PCSK9 level independently predicted CV events and death in HD patients. These results suggest the importance of future studies regarding the effect of PCSK9 inhibition on reduction of CV events.

Background. In 2009, the Oxford classification was developed as a pathological classification system for immunoglobulin A nephropathy (IgAN) to predict the risk of disease progression. The aim of this retrospective study was to evaluate the clinical and pathologic relevance of the Oxford classification in Korean patients with a pathologic diagnosis of IgAN. Patients and methods. We reviewed the renal pathology archives from January 2000 to December 2006 at Seoul St Mary’s Hospital in Korea and identified 273 patients, who were diagnosed as having IgAN. We enrolled 197 patients who were available for further clinicopathologic analysis. All cases of IgAN were categorized according to the WHO classification, the semiquantitative classification and the Oxford classification. These pathologic classifications were compared. The clinical and laboratory findings at the time of biopsy were compared with those at the end of the follow-up according to the Oxford classification. Results. When three pathologic classifications were compared, M1, S1, E1, T1 or T2 were associated with a higher score in the activity index. S1, T1 or T2 were associated with a higher score in the chronicity index and a higher grade in the WHO classification. The clinical and laboratory findings were compared according to the Oxford classification. At the time of biopsy, the proteinuria in patients with M1 was more than that of M0 (P ¼ 0.035). At the end of follow-up, the number of antihypertensive drugs taken among patients with M1 was greater than that of patients with M0 (P ¼ 0.001). At the time of biopsy, the proteinuria of patients with S1 was greater than that of S0 patients (P ¼ 0.009). At the end of follow-up, the number of patients who received immunosuppressants was increased as the grade of T increased (P ¼ 0.000). At the end point of the followup, the estimated glomerular filtration rate (eGFR) decreased as the grade of T increased (P ¼ 0.008). The time-average proteinuria after adjusting the initial proteinuria increased significantly with increasing degree of T( P¼ 0.000). Levels of tubular atrophy/interstitial fibrosis were predictive for survival from end-stage renal disease or of having a 50% reduction of eGFR. Conclusion. The pathologic variables of the Oxford classification correlated significantly with other classifications (the WHO classification and the semiquantitative classification). The Oxford classification is a simple method for predicting renal outcome and differentiating between active and chronic lesions. We suggest that the Oxford classification offers an advantage for determining treatment policy for patients with IgAN.

Purpose The immunochemical fecal occult blood test (iFOBT) is a useful method to screen for lower gastrointestinal (GI) bleeding-related lesions. However, few studies have investigated the diagnostic utility of iFOBT in chronic kidney disease (CKD).