Ga Young Heo

Background: The impact of facility-level comorbidity burden on the prognosis of hemodialysis patients remains unclear. This study aimed to investigate the association between facility-level comorbidity burden and hemodialysis outcomes. Methods: We examined 15,481 participants receiving hemodialysis at primary clinics participating in the Periodic Hemodialysis Quality Assessment by Health Insurance Review and Assessment Service in Korea. Facility-level comorbidity burden, defined as the sum of the Charlson Comorbidity Index of all patients divided by the number of nurses in each hemodialysis center, was the primary predictor. The primary outcome was major adverse cardiac and cerebrovascular events (MACCE). Results: During a median follow-up of 6.8 years, MACCE and all-cause mortality occurred in 9,797 (63.3%) and 8,513 participants (55.0%), respectively. Participants in the highest facility-level comorbidity burden had the highest incidence rates of both MACCE and all-cause mortality. Hazard ratios (HRs) of MACCE and all-cause mortality in the highest vs. the lowest quartile were 1.10 (95% confidence interval [CI], 1.03–1.18) and 1.14 (95% CI, 1.06–1.22), respectively. Applying the facility-level comorbidity burden as a continuous variable, each 10-unit increase in facility-level comorbidity burden was associated with a 4% and 8% higher risk of MACCE and all-cause mortality, respectively. These associations remained consistent across subgroups. Conclusion: Our findings revealed that the facility-level comorbidity burden in hemodialysis centers was associated with a higher hazard of poor outcomes in patients undergoing hemodialysis.

Koh HB, et al. Yonsei Med J. 2026 Jan;67(1):17-26. https://doi.org/10.3349/ymj.2025.0065

Background: Chronic kidney disease (CKD) is a major global health problem owing to its progressive nature, complications, and substantial healthcare burden. The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend outpatient visit intervals based on CKD severity; however, adherence to these recommendations and the factors influencing the visit interval remain unclear. Methods: This retrospective observational study included 13,621 patients with CKD treated at a tertiary hospital in South Korea. Using electronic medical records, we used linear regression and Shapley Additive exPlanations (SHAP), a method for interpreting model prediction, to assess the influence of clinical, demographic, and healthcare utilization factors on outpatient visit intervals. Key variables included the CKD stage, comorbidities, age, distance to the hospital, and physician assignment. Results: Visit intervals shortened as CKD severity increased, although variability was substantial. Adherence to KDIGO-recommended intervals was higher in earlier CKD stages, but declined in intermediate and advanced stages, except for stage G5–A3, where 90.0% of visits met guidelines. Shorter intervals were associated with advanced stage, older age, greater healthcare use, and shorter distance to the hospital. SHAP analysis confirmed these predictors, identifying CKD stage as the dominant factor and revealing notable physician-level variation. Conclusion: CKD stage was the primary determinant of outpatient follow-up intervals, but adherence to KDIGO recommendations varied across stages. Visit schedules were also affected by age, comorbidities, healthcare utilization, accessibility, and physician practice. These findings underscore the need for tailored follow-up strategies that reflect both disease severity and clinical context.

Key Points: Risk of all-cause mortality was significantly lower in KoreaN Cohort Study for Outcome in Patients with CKD group than that in the Chronic Renal Insufficiency Cohort group. Asian cohorts exhibited steeper eGFR decline slopes than that of the Black and White cohorts. Tailored clinical approaches and ethnicity-stratified studies are required to improve CKD management. Background: Ethnic differences in CKD progression remain understudied, particularly between Asian and Western populations. Therefore, we aimed to investigate ethnic disparities in CKD progression by comparing nationwide cohorts from South Korea (the KoreaN Cohort Study for Outcome in Patients with CKD [KNOW-CKD]) and the United States (the US Chronic Renal Insufficiency Cohort [CRIC]). Methods: A total of 4953 participants were included (69% from CRIC and 31% from KNOW-CKD). The primary outcome was CKD progression, defined as a 50% or greater decline of eGFR or kidney failure requiring KRT. In the secondary outcome analysis, we compared eGFR decline rates and all-cause mortality. Results: Of the 4953 participants, CKD progression occurred in 1285 and 570 in the KNOW-CKD and CRIC cohorts, with incidence rates of 67.9 and 41.7 per 1000 person-years, respectively. The hazard ratio for the KNOW-CKD compared with CRIC was 1.66 (95% confidence interval [CI], 1.45 to 1.89). The annual eGFR decline was steeper in KNOW-CKD participants than in CRIC participants (−2.51 versus −1.14 ml/min per 1.73 m ² ). Asian participants from the CRIC cohort exhibited a similar eGFR slope (95% CIs) (−2.10 [−2.69 to −1.52]) to those from KNOW-CKD (−2.50 [−2.67 to −1.52]), while the slope was −1.47 (−1.61 to −1.33) and −0.81 (−0.92 to −0.70) ml/min per 1.73 m ² per year for Black and White participants, respectively. However, the risk of mortality was significantly lower in KNOW-CKD participants compared with CRIC participants (hazard ratio, 0.51; 95% CI, 0.38 to 0.68). Conclusions: CKD progression was faster in the Korean cohort than in the US cohort, with Asian participants in both cohorts showing similar eGFR decline rates. However, the Korean cohort had a lower risk of mortality, indicating potential ethnic or regional differences in disease progression and survival.

Key Points: A higher frequency of adding salt was significantly associated with an increased risk of CKD development in the high polygenic risk score-hypertension group. However, no significant association was observed between salt intake frequency and CKD in the low and intermediate polygenic risk score-hypertension groups. Background: Although excessive salt intake increases the risk of adverse health outcomes, its effects may vary among individuals, supporting the concept of salt sensitivity. This study aimed to investigate whether genetic factors, represented by the polygenic risk score for hypertension (PRS-hypertension), could act as determinants of salt sensitivity and modify the effect of salt intake on incident CKD. Methods: Data from UK Biobank were used, including participants of White British ancestry without preexisting CKD or hypertension. The primary exposures were the self-reported frequency of adding salt to food and the PRS-hypertension tertile group. The primary outcome was the development of CKD, analyzed using multivariable Cox models. Results: Among 258,555 participants (mean age 55.3±8.1 years, 44% men), 8686 (3%) cases of incident CKD were observed during median follow-up of 13.7 years. A significant interaction was observed between PRS-hypertension and frequency of adding salt with respect to CKD risk ( P for multiplicative interaction = 0.001). In the high PRS-hypertension group, compared with those who rarely/never added salt to food, the adjusted hazard ratio was 1.11 (95% confidence interval [CI], 1.02 to 1.21) for those who sometimes added salt and 1.23 (95% CI, 1.14 to 1.36) for those who usually/always added salt. In addition, there were significant additive interactions between high PRS-hypertension and usually/always adding salt on the risk of incident CKD compared with those with low PRS-hypertension and who rarely/never added salt (relative excess risk due to interaction=0.19; 95% CI, 0.03 to 0.34; attributable proportion=0.15; 95% CI, 0.04 to 0.27). Conclusions: PRS-hypertension modified the association between frequency of adding salt and incident CKD. These findings suggest that the effects of high sodium intake on kidney function may be influenced by genetic factors.

The clinical implications of genetic risk for hypertension (HTN) and high low-density lipoprotein cholesterol (LDL-C) levels in incident chronic kidney disease (CKD) are unknown. This study aimed to examine whether polygenic risk scores (PRSs) for these two factors can predict the development of CKD. We included 245,893 participants enrolled in UK Biobank during 2006-2010 and followed up until 2022. The primary exposures were the PRS for HTN (PRS HTN) and high LDL-C concentration (PRS LDL-C). The primary outcome was incident CKD, assessed using cause-specific competing-risk models. During a median follow-up of 13.7 years (interquartile range, 13.0-14.3 years), 7,771 individuals experienced CKD. A 1-standard deviation higher PRS HTN was associated with a 7% higher risk of incident CKD (hazard ratio [HR], 1.07; 95% confidence interval [CI], 1.05-1.10). However, PRS LDL-C showed no significant association with incident CKD. In a combined association analysis based on the four groups classified by the median values of PRS, the HRs were 1.03 (95% CI, 0.97-1.10) in the high LDL-C-risk group and 1.13 (95% CI, 1.06-1.20) in both the high HTN group and the combined high-risk group, compared with the reference group. This study showed that individuals with a higher genetic predisposition to HTN were more likely to develop CKD than those predisposed to a high LDL-C concentration. Additionally, higher genetic predispositions for these two factors did not synergically contribute to the risk of CKD.

Key Points: A higher medication burden was associated with a higher risk of adverse events in patients receiving maintenance hemodialysis. Medication burden can serve as a clinically relevant risk indicator for cardiovascular events and all-cause death in patients on maintenance hemodialysis. Background: A high medication burden is associated with adverse outcomes. Although patients with ESKD have a substantial medication burden, the relationship between the number of medications in use and clinical outcomes in these patients remains unclear. Hence, this study aimed to investigate the prognostic implications of medication burden regarding adverse outcomes in patients with ESKD on maintenance hemodialysis. Methods: We analyzed 29,690 patients receiving maintenance hemodialysis who participated in the Periodic Hemodialysis Quality Assessment conducted by the Health Insurance Review and Assessment Service. The exposure of interest was the number of routinely prescribed oral medications. The main outcome was a composite of nonfatal cardiovascular events (nonfatal myocardial infarction, coronary revascularization, nonfatal stroke, or hospitalization for heart failure) or all-cause death (major adverse cardiac and cerebrovascular events [MACCEs]). The secondary outcomes were the individual components of the primary outcome. Results: During a follow-up period of 146,749 person-years (median, 6.0 years), MACCEs occurred in 17,573 patients (59.2%). Higher medication burden was associated with progressively higher incidence of MACCEs (84.7, 107.2, 130.2, and 168.9 events per 1000 person-years in Q1–Q4, respectively). In a multivariable Cox proportional hazard model, the adjusted hazard ratios (95% confidence intervals) for the second, third, and highest quartiles were 1.05 (1.00 to 1.10), 1.12 (1.07 to 1.17), and 1.27 (1.21 to 1.33), respectively, compared with the lowest quartile. In continuous modeling, each increase in the number of medication was associated with a 1.03-fold (95% confidence interval, 1.03 to 1.04) higher risk of the primary outcome. Conclusion: A high medication burden was independently associated with higher risk of adverse cardiovascular outcomes and all-cause death in patients receiving maintenance hemodialysis. These findings suggest that a high medication burden could be a useful indicator of adverse clinical outcomes in patients undergoing hemodialysis.

BACKGROUND: Atrial fibrillation (AF) can lead to stroke, heart failure, and mortality and has a greater prevalence in dialysis patients than in the general population. Several studies have suggested that uremic toxins may contribute to the development of AF. However, the association between dialysis adequacy and incident AF has not been well established. METHODS: In this retrospective nationwide cohort study, we analyzed data from the Korean National Periodic Hemodialysis Quality Assessment from 2013 to 2015 of patients who received outpatient maintenance hemodialysis 3× a week. The main exposure was single pooled Kt/V (spKt/V), which is the dialysis adequacy index, and the primary outcome was the development of AF. For the primary analysis, patients were categorized into quartiles according to baseline spKt/V. The lowest quartile, representing the lowest adequacy, was used as the reference group. Fine-Gray subdistribution hazard models were used, treating all-cause mortality as a competing risk. RESULTS: Of 25 173 patients, the mean age was 60 (51–69) years, and 14 772 (58.7%) were men. During a median follow-up of 5.7 years, incident AF occurred in a total of 3883 (15.4%) patients. Participants with a higher spKt/V tended to have lower AF incidence. In survival analysis, a graded association was observed between the risk of incident AF and spKt/V quartiles: subdistribution hazard ratios and 95% CIs for the second, third, and the highest quartile compared with the lowest quartile were 0.90 (95% CI, 0.82–0.98), 0.84 (95% CI, 0.77–0.93), and 0.79 (95% CI, 0.72–0.88), respectively. CONCLUSIONS: This nationwide cohort study showed that a higher spKt/V is associated with a reduced risk of incident AF. These findings suggests that reducing uremic toxin burden through enhanced dialysis clearance may be associated with a lower risk of AF development in patients undergoing maintenance hemodialysis.

Background: Insomnia is a known risk factor for cardio-cerebrovascular disease in the general population; however, its effect on cardio-cerebrovascular outcomes in end-stage kidney disease patients is unclear. Therefore, this study aimed to investigate the association between cardio-cerebrovascular outcomes and insomnia in patients who initiated maintenance dialysis. Methods: This study used nationwide Korean health insurance claims data to analyze 79 420 patients who initiated maintenance dialysis from January 2009 to December 2017. Insomnia was defined using claim codes and sleep medication prescription data. Patients were categorized according to the presence of insomnia before and after dialysis initiation: (i) no insomnia, (ii) insomnia before dialysis only (improved insomnia), (iii) insomnia after dialysis only (developed insomnia) and (iv) insomnia in both periods (persistent insomnia). The primary and secondary outcomes were major adverse cardiac and cerebrovascular events (MACCE) and all-cause mortality, respectively. The outcome risks were estimated by Cox regression models with inverse probability of treatment weighting. Results: The mean age was 61.4 ± 13.4 years, and 39.7% were women. During the transition period from pre-dialysis to maintenance dialysis, 13.2% experienced insomnia. The insomnia groups showed significantly higher risks for MACCE [weighted hazard ratios (95% confidence intervals): developed insomnia, 1.26 (1.25–1.28); improved insomnia, 1.31 (1.29–1.33); persistent insomnia, 1.39 (1.37–1.41)] and higher all-cause mortality risks than the no insomnia group. The insomnia-related cardio-cerebrovascular disease risk elevation was more prominent in younger and male patients. Conclusions: Insomnia may increase cardio-cerebrovascular disease and all-cause mortality risk among end-stage kidney disease patients who initiate maintenance dialysis.