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Background Urolithiasis has been infrequently implicated to have a causal association with chronic kidney disease (CKD). Recently, several studies have demonstrated the relationship between urolithiasis and CKD. However, the generalizability of their results is limited. This study aimed to investigate the association between urolithiasis and the risk of incident CKD. Methods This longitudinal cohort study used the National Health Insurance Service data, including 219 570 Korean adults with incident urolithiasis requiring procedural interventions and without prior kidney disease and 219 570 age- and sex-matched controls without urolithiasis between 1 January 2002 and 31 December 2020. Primary outcome was the development of CKD, defined by an estimated glomerular filtration rate <60 ml/min/1.73 m2 for at least two consecutive measurements at least 90 days apart. The risk for incident CKD was further examined using the outcome defined by newly occurring diagnostic codes indicating CKD. Results Over a mean follow-up of 6 years, 12 338 (2.8%) primary outcome events of CKD were observed (incidence rate 4.6/1000 person-years). Per multivariable Cox analysis, urolithiasis was associated with a higher risk of incident CKD [adjusted hazard ratio 1.41 (95% confidence interval 1.36–1.46)]. This association remained consistent across all clinically relevant subgroups and when the CKD outcome was defined based on the diagnostic codes in the sensitivity analysis. Conclusions In this large national cohort study, patients with urolithiasis were associated with a higher risk of incident CKD than those without urolithiasis. Further studies are warranted to establish the benefits of preventing urolithiasis in reducing CKD development. [ABSTRACT FROM AUTHOR]

Background: The 2021 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline for the management of blood pressure (BP) in chronic kidney disease (CKD) recommends a target systolic BP of <120 mmHg as this target can provide cardiovascular benefits. However, it remains unclear whether implementing the new BP target could improve kidney outcomes. Methods: The association between the 2021 KDIGO BP target and CKD progression was examined and compared with the 2012 KDIGO BP target among 1724 participants included in the KoreaN Cohort Study for Outcomes in Patients With CKD. The main exposure was the BP status categorized according to the 2012 or 2021 KDIGO guideline: (1) controlled within the 2021 target, (2) controlled within the 2012 target only, and (3) above both targets. The primary outcome was a composite kidney outcome of ≥50% decline in the estimated glomerular filtration rate from baseline or the initiation of kidney replacement therapy during the follow‐up period. Results: Composite kidney outcomes occurred in 650 (37.7%) participants during the 8078 person‐years of follow‐up (median, 4.9 years). The incidence rates of this outcome were 55, 66.5, and 116.4 per 1000 person‐years in BP controlled within the 2021 and 2012 KDIGO targets, and BP above both targets, respectively. In the multivariable cause‐specific hazard model, hazard ratios for the composite outcome were 0.76 (95% confidence interval (CI), 0.60–0.95) for BP controlled within the 2021 target and 1.36 (95% CI, 1.13–1.64) for BP above both targets, compared with BP controlled within 2012 target only. Conclusion: The newly lowered BP target by the 2021 KDIGO guideline was associated with improved kidney outcome compared with BP target by the 2012 KDIGO guideline. [ABSTRACT FROM AUTHOR]

Background: Elevated blood pressure and intrarenal renin-angiotensin system activity are closely related to chronic kidney disease (CKD) progression. However, interrelationship between blood pressure and intrarenal renin-angiotensin system activity on the risk of CKD progression is unknown. Methods: We analyzed 2076 participants from the Korean Cohort Study for Outcomes in Patients With CKD. The main exposure was systolic blood pressure (SBP). The urinary angiotensinogen-to-creatinine ratio was stratified according to the median value (3.65 μg/gCr). The primary outcome was a composite kidney outcome of a ≥50% decline in estimated glomerular filtration rate from baseline measurement or initiation of kidney replacement therapy. Results: During 10 550 person-years of follow-up (median, 5.2 years), the composite outcome occurred in 800 (38.5%) participants. In the multivariable cause-specific hazard model, higher SBP was associated with an increased risk of CKD progression. There was a significant interaction between SBP and urinary angiotensinogen-to-creatinine ratio on the risk of the primary outcome (P value for interaction=0.019). In patients with urinary angiotensinogen-to-creatinine <3.65 μg/gCr, the hazard ratios (95% CIs) for SBP 120 to 129, 130 to 139, and ≥140 mmHg were 1.46 (1.07–1.99), 1.71 (1.25–2.35), and 2.40 (1.73–3.32), respectively, compared with SBP <120 mmHg. However, these associations were not observed in patients with urinary angiotensinogen-to-creatinine ≥3.65 μg/gCr. Conclusions: In this prospective CKD cohort, higher SBP was associated with CKD progression when urinary angiotensinogen levels were low, while this association was not seen when urinary angiotensinogen levels were high. This finding suggests that intrarenal renin-angiotensin system activity may modify the relationship between SBP and adverse kidney outcome. [ABSTRACT FROM AUTHOR]

Fluid balance is a critical prognostic factor for patients with severe acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). This study evaluated whether repeated fluid balance monitoring could improve prognosis in this clinical population. This was a multicenter retrospective study that included 784 patients (mean age, 67.8 years; males, 66.4%) with severe AKI requiring CRRT during 2017–2019 who were treated in eight tertiary hospitals in Korea. Sequential changes in total body water were compared between patients who died (event group) and those who survived (control group) using mixed-effects linear regression analyses. The performance of various machine learning methods, including recurrent neural networks, was compared to that of existing prognostic clinical scores. After adjusting for confounding factors, a marginal benefit of fluid balance was identified for the control group compared to that for the event group (p = 0.074). The deep-learning model using a recurrent neural network with an autoencoder and including fluid balance monitoring provided the best differentiation between the groups (area under the curve, 0.793) compared to 0.604 and 0.606 for SOFA and APACHE II scores, respectively. Our prognostic, deep-learning model underlines the importance of fluid balance monitoring for prognosis assessment among patients receiving CRRT. [ABSTRACT FROM AUTHOR]

Objectives Despite the preclinical evidence on protective effects of colchicine against kidney fibrosis, whether colchicine could delay the progression of chronic kidney disease (CKD) in humans remains unknown. This study examined the association between long-term colchicine use and risk of adverse kidney outcome in patients with CKD who were treated for hyperuricaemia or chronic gout. Methods We conducted a multicentre, nested, case-control study in three Korean hospitals. Patients were aged ≥19 years; had CKD G3–G4; and used drugs including colchicine, allopurinol and febuxostat for hyperuricaemia or chronic gout during the period from April 2000 to October 2020. Patients with CKD progression, which was defined as ≥40% decrease from the baseline estimated glomerular filtration rate or the onset of kidney failure with replacement therapy, were matched to controls based on follow-up time, age and sex. Results Overall, 3085 patients with CKD progression were matched to 11   715 control patients. Multivariate conditional logistic regression analysis showed that patients with ≥90 cumulative daily colchicine doses were associated with a lower risk of CKD progression [adjusted odds ratio (AOR), 0.77; 95% CI: 0.61, 0.96] than non-users. In the sensitivity analysis with matched CKD stages, the AOR was 0.77 (95% CI: 0.62, 0.97). This association was more pronounced in patients without diabetes or hypertension, and in patients with CKD G3. Conclusion Colchicine use is associated with a lower risk of adverse kidney outcomes in CKD patients with hyperuricaemia, or chronic gout. [ABSTRACT FROM AUTHOR]

Background Optimal blood pressure (BP) control is a major therapeutic strategy to reduce adverse cardiovascular events (CVEs) and mortality in patients with chronic kidney disease (CKD). We studied the association of BP with adverse cardiovascular outcome and all-cause death in patients with CKD. Methods Among 2238 participants from the KoreaN cohort study for Outcome in patients With CKD (KNOW-CKD), 2226 patients with baseline BP measurements were enrolled. The main predictor was systolic BP (SBP) categorized by five levels: <110, 110–119, 120–129, 130–139 and ≥140 mmHg. The primary endpoint was a composite outcome of all-cause death or incident CVEs. We primarily used marginal structural models (MSMs) using averaged and the most recent time-updated SBPs. Results During the follow-up of 10 233.79 person-years (median 4.60 years), the primary composite outcome occurred in 240 (10.8%) participants, with a corresponding incidence rate of 23.5 [95% confidence interval (CI) 20.7–26.6]/1000 patient-years. MSMs with averaged SBP showed a U-shaped relationship with the primary outcome. Compared with time-updated SBP of 110–119 mmHg, hazard ratios (95% CI) for <110, 120–129, 130–139 and ≥140 mmHg were 2.47 (1.48–4.11), 1.29 (0.80–2.08), 2.15 (1.26–3.69) and 2.19 (1.19–4.01), respectively. MSMs with the most recent SBP also showed similar findings. Conclusions In Korean patients with CKD, there was a U-shaped association of SBP with the risk of adverse clinical outcomes. Our findings highlight the importance of BP control and suggest a potential hazard of SBP <110 mmHg. [ABSTRACT FROM AUTHOR]

Introduction: Fluid overload and sleep apnea (SA) are known risk factors for mortality in dialysis patients. Although incidence and severity of SA were shown higher in peritoneal dialysis (PD) patients than in hemodialysis patients, data regarding the association of SA with body fluid status and mortality are limited. Therefore, the association of SA with body fluid status and mortality were investigated in a prospective cohort with patients undergoing PD. Methods: The present study included 103 prevalent PD patients who were followed up for median 70 months. At baseline, the subjects underwent in‐home polysomnography, bioelectrical impedance analysis, and urea kinetics. Excessive daytime sleepiness and sleep quality were assessed using sleep questionnaires. SA was defined as apnea/hypopnea index higher than 15 events per hour. Results: Sleep apnea was diagnosed in 57 (55.3%) patients (SA group); the subjects had significantly higher extracellular water (10.3 ± 1.4 vs. 9.2 ± 1.8, p = 0.001) and lower residual kidney function (RKF) (3.3 ± 3.3 vs. 5.9 ± 7.2, p = 0.02) compared with subjects in the non‐SA group. SA was significantly associated with RKF [odds ratio, 0.84; 95% confidence interval (CI), 0.73–0.97] in multivariable logistic regression analysis. In multivariable Cox regression models, SA was a significant predictor of mortality in PD patients (adjusted hazard ratio, 5.74; 95% CI, 1.09–30.31) after adjusting for well‐known risk factors. Conclusions: Sleep apnea was very common in PD patients and significantly associated with lower RKF. SA was also a novel risk predictor of mortality in PD patients. [ABSTRACT FROM AUTHOR]

Background and Aims: The optimal low-density lipoprotein cholesterol (LDL-C) level to prevent cardiovascular disease in chronic kidney disease (CKD) patients remains unknown. This study aimed to explore the association of LDL-C levels with adverse cardiovascular and kidney outcomes in Korean CKD patients and determine the validity of "the lower, the better" strategy for statin intake.Methods and Results: A total of 1886 patients from the KoreaN cohort study for Outcome in patients With CKD (KNOW-CKD) were included. Patients were classified into four LDL-C categories: <70, 70-99, 100-129, and ≥130 mg/dL. The primary outcome was extended major adverse cardiovascular events (eMACEs). Secondary outcomes included all-cause mortality, and CKD progression. During the follow-up period, the primary outcome events occurred in 136 (7.2%) patients (16.9 per 1000 person-years). There was a graded association between LDL-C and the risk of eMACEs. The hazard ratios (95% confidence intervals) for LDL-C categories of 70-99, 100-129, and ≥130 mg/dL were 2.06 (1.14-3.73), 2.79 (1.18-6.58), and 4.10 (1.17-14.3), respectively, compared to LDL-C <70 mg/dL. Time-varying analysis showed consistent findings. The predictive performance of LDL-C for eMACEs was affected by kidney function. Higher LDL-C levels were also associated with significantly higher risks of CKD progression. However, LDL-C level was not associated with all-cause mortality.Conclusions: This study showed a graded relationship between LDL-C and the risk of adverse cardiovascular outcome in CKD patients. The lowest risk was observed with LDL-C <70 mg/dL, suggesting that a lower LDL-C target may be acceptable. [ABSTRACT FROM AUTHOR]

Background Increased body mass index (BMI) has been associated with a higher risk of severe coronavirus disease 2019 (COVID-19) infections. However, whether obesity is a risk factor for contracting COVID-19 has hardly been investigated so far. Methods We examined the association between BMI level and the risk of COVID-19 infection in a nationwide case-control study comprised of 3788 case patients confirmed to have COVID-19 between 24 January and 9 April 2020 and 15 152 controls matched by age and sex, who were aged 20 years or more and underwent National Health Insurance Service (NHIS) health examinations between 2015−2017, using data from the Korean NHIS with linkage to the Korea Centers for Disease Control and Prevention data. Our primary exposure of interest was BMI level, categorized into 4 groups: <18.5 (underweight), 18.5–22.9 (normal weight), 23–24.9 (overweight), and ≥25 kg/m2 (obese). Results Of the entire 18 940 study participants, 11 755 (62.1%) were women, and the mean age of the study participants was 53.7 years (standard deviation, 13.8). In multivariable logistic regression models adjusted for sociodemographic, comorbidity, laboratory, and medication data, there was a graded association between higher BMI levels and higher risk of COVID-19 infection. Compared to normal-weight individuals, the adjusted odds ratios in the overweight and obese individuals were 1.13 (95% confidence interval [CI], 1.03–1.25) and 1.26 (95% CI, 1.15–1.39), respectively. This association was robust across age and sex subgroups. Conclusions Higher BMI levels were associated with a higher risk of contracting COVID-19. [ABSTRACT FROM AUTHOR]