Predictive performance of the new race-free Chronic Kidney Disease Epidemiology Collaboration equations for kidney outcome in Korean patients with chronic kidney disease

The new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations without a race coefficient have gained recognition across the United States. We aimed to test whether these new equations performed well in Korean patients with chronic kidney disease (CKD). Methods: This study included 2,149 patients with CKD G1–G5 without kidney replacement therapy from the Korean Cohort Study for Outcome in Patients with CKD (KNOW-CKD). The estimated glomerular filtration rate (eGFR) was calculated using the new CKD-EPI equations with serum creatinine and cystatin C. The primary outcome was 5-year risk of kidney failure with replacement therapy (KFRT). Results: When we adopted the new creatinine equation [eGFRcr (NEW)], 81 patients (23.1%) with CKD G3a based on the current creatinine equation (eGFRcr) were reclassified as CKD G2. Accordingly, the number of patients with eGFR of <60 mL/min/1.73 m2 decreased from 1,393 (64.8%) to 1,312 (61.1%). The time-dependent area under the receiver operating characteristic curve for 5-year KFRT risk was comparable between the eGFRcr (NEW) (0.941; 95% confidence interval [CI], 0.922–0.960) and eGFRcr (0.941; 95% CI, 0.922–0.961). The eGFRcr (NEW) showed slightly better discrimination and reclassification than the eGFRcr. However, the new creatinine and cystatin C equation [eGFRcr-cys (NEW)] performed similarly to the current creatinine and cystatin C equation. Furthermore, eGFRcr-cys (NEW) did not show better performance for KFRT risk than eGFRcr (NEW). Conclusion: Both the current and the new CKD-EPI equations showed excellent predictive performance for 5-year KFRT risk in Korean patients with CKD. These new equations need to be further tested for other clinical outcomes in Koreans.

Executive summary of the Korean Society of Nephrology 2021 clinical practice guideline for optimal hemodialysis treatment

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists’ support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient’s condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There are also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

Pericoronary fat attenuation index in computed tomography angiography is associated with mortality in end-stage renal disease

An increased pericoronary fat attenuation index (FAI) on computed tomography angiography (CTA) is associated with increased all-cause and cardiac mortality in the general population. However, the ability of pericoronary FAI to predict long-term outcomes in chronic kidney disease (CKD) patients is unknown. Methods: In this single-center retrospective longitudinal cohort study, we assessed the utility of CTA-based pericoronary FAI measurement to predict mortality of CKD patients, including those with end-stage renal disease (ESRD). Mapping and analysis of pericoronary FAI involved three major proximal coronary arteries. The prognostic value of pericoronary FAI for long-term mortality was assessed with multivariable Cox regression models. Results: Among 268 CKD participants who underwent coronary CTA, 209 participants with left anterior descending artery (LAD) FAI measurements were included. The pericoronary FAI measured at the LAD was not significantly associated with adjusted risk of allcause mortality (hazard ratio [HR], 2.08; 95% confidence interval [CI], 0.94–3.51) in any CKD group. However, ESRD patients with elevated pericoronary FAI values had a greater adjusted risk of all-cause mortality compared with the low-FAI group (HR, 2.26; 95% CI, 1.11–4.61). Conclusion: The pericoronary FAI measured at the LAD predicted long-term mortality in patients with ESRD, which could provide an opportunity for early primary intervention in ESRD patients.

Association between blood pressure and the risk of chronic kidney disease in treatment-naïve hypertensive patients

Although hypertension is a well-known risk factor for chronic kidney disease (CKD), the blood pressure (BP) at which antihypertensive interventions should be initiated remains to be determined. Therefore, we investigated the association between BP and CKD in treatment-naïve individuals. Methods: This prospective cohort study considered 7,343 individuals in the Korean Genome and Epidemiology Study who were not taking antihypertensive medications. Subjects were categorized into six groups according to their systolic BP (SBP) and five groups according to their diastolic BP (DBP). The primary outcome was incident CKD, which was defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m2 or the development of proteinuria. The secondary outcome was incident cardiovascular disease (CVD). Results: In the time-varying Cox models, the hazard ratios (95% confidence interval [CI]) for CKD were 1.39 (1.10–1.77) with SBP 130–139 mmHg, 1.79 (1.40–2.28) with SBP 140–159 mmHg, and 3.22 (2.35–4.40) with SBP ≥ 160 mmHg, compared with SBP 100–119 mmHg. In addition, the hazard ratios (95% CI) for CKD were 1.88 (1.48–2.37) with DBP 90–99 mmHg and 4.30 (3.20– 5.76) with DBP ≥ 100 mmHg, compared with DBP 70–79 mmHg. A significantly increased CVD risk was also observed in subjects with SBP ≥ 130 mmHg or DBP ≥ 90 mmHg. Conclusion: Our findings indicate that SBP ≥ 130 mmHg and DBP ≥ 90 mmHg are associated with an increased risk of CKD. Therefore, BP-lowering strategies should be considered starting at those thresholds to prevent CKD development.

Metformin use and cardiovascular outcomes in patients with diabetes and chronic kidney disease: a nationwide cohort study

Background@#Metformin has recently been shown not to increase the risk of lactic acidosis in patients with chronic kidney disease (CKD). Thus, the criteria for metformin use in this population has expanded. However, the relationship between metformin use and clinical outcomes in CKD remains controversial. @*Methods@#This study considered data from 97,713 diabetes patients with an estimated glomerular filtration rate of <60 mL/min/1.73 m2. The primary outcome was major adverse cardiac and cerebrovascular events (MACCE), and the secondary outcomes were all-cause mortality and incident end-stage renal disease (ESRD). @*Results@#Metformin users had a significantly higher risk of MACCE than non-users (hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.14–1.26; p < 0.001). However, metformin users had a lower risk of all-cause mortality (HR, 0.78; 95% CI, 0.74–0.81; p < 0.001) and ESRD (HR, 0.44; 95% CI, 0.42–0.47; p < 0.001) during follow-up than non-users did. The relationships between metformin use and clinical outcomes remained consistent in propensity score matching analyses and subgroup analyses of patients with adequate adherence to anti-diabetes medication. @*Conclusion@#Treatment with metformin was associated with an increased risk of MACCE in patients with diabetes and CKD. However, metformin users had a lower risk of all-cause mortality and ESRD during follow-up than non-users did. Therefore, metformin needs to be carefully used in patients with CKD.

Executive Summary of the Korean Society of Nephrology 2021 Clinical Practice Guideline for Optimal Hemodialysis Treatment

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists’ support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient’s condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There is also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

Incidence of Acute Kidney Injury after Adrenalectomy in Patients with Primary Aldosteronism

BACKGROUND@#Aldosterone-induced glomerular hyperfiltration can lead to masked preoperative renal dysfunction in primary aldosteronism(PA) patients. We evaluated whether PA patients had a higher prevalence of acute kidney injury (AKI) after unilateral adrenalectomy. In addition, we identified risk factors for AKI in these subjects.@*METHODS@#This retrospective study included 107 PA patients, and 186 pheochromocytoma patients as a control group, all of whom underwent adrenalectomy between January 2006 and November 2017 at Yonsei University Severance Hospital. The primary outcome was AKI within 48 hours after adrenalectomy. Univariate and multivariate logistic regression analyses were performed to identify predictors of AKI after adrenalectomy.@*RESULTS@#Overall incidence of AKI was 49/293 (16.7%). In PA patients, the incidence of AKI was 29/107 (27.1%). In contrast, incidence of AKI was 20/186 (10.7%) in pheochromocytoma patients. Univariate and multivariate logistic regression analysis both showed a higher risk of postoperative AKI in PA patients compared to pheochromocytoma patients. In addition, old age, diabetes, longer duration of hypertension, lower preoperative estimated glomerular filtration rate, high aldosterone-cortisol ratio (ACR) and lateralization index (LI) were identified as independent risk factors for postoperative AKI in PA patients after unilateral adrenalectomy.@*CONCLUSION@#Incidence and risk of postoperative AKI were significantly higher in PA patients after surgical treatment. High ACR on the tumor side and high LI were associated with higher risk of AKI in PA patients compared to pheochromocytoma patients.

Body mass index is inversely associated with mortality in patients with acute kidney injury undergoing continuous renal replacement therapy

BACKGROUND: Many 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. METHODS: We 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. RESULTS: Patients 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). CONCLUSION: This study showed that a higher BMI confer a survival benefit over a lower BMI in AKI patients undergoing CRRT.

Baseline Cardiovascular Characteristics of Adult Patients with Chronic Kidney Disease from the KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease (KNOW-CKD)

Cardiovascular disease (CVD) is the most common cause of death in patients with chronic kidney disease (CKD). We report the baseline cardiovascular characteristics of 2,238 participants by using the data of the KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease (KNOW-CKD) study. The cohort comprises 5 subcohorts according to the cause of CKD: glomerulonephritis (GN), diabetic nephropathy (DN), hypertensive nephropathy (HTN), polycystic kidney disease (PKD), and unclassified. The average estimated glomerular filtration rate (eGFR) was 50.5 ± 30.3 mL/min⁻¹/1.73 m⁻² and lowest in the DN subcohort. The overall prevalence of previous CVD was 14.4% in all patients, and was highest in the DN followed by that in the HTN subcohort. The DN subcohort had more adverse cardiovascular risk profiles (higher systolic blood pressure [SBP], and higher levels of cardiac troponin T, left ventricular mass index [LVMI], coronary calcium score, and brachial-ankle pulse wave velocity [baPWV]) than the other subcohorts. The HTN subcohort exhibited less severe cardiovascular risk profiles than the DN subcohort, but had more severe cardiovascular risk features than the GN and PKD subcohorts. All these cardiovascular risk profiles were inversely correlated with eGFR. In conclusion, this study shows that the KNOW-CKD cohort exhibits high cardiovascular burden, as other CKD cohorts in previous studies. Among the subcohorts, the DN subcohort had the highest risk for CVD. The ongoing long-term follow-up study up to 10 years will further delineate cardiovascular characteristics and outcomes of each subcohort exposed to different risk profiles.