Background: The incidences of atrial fibrillation (AF) and chronic kidney disease (CKD) are increasing, and AF is prevalent in patients with CKD. However, few studies have investigated the incidence or association of AF in a large CKD population from a longitudinal study. Methods and Results: From a nationwide cohort, a total of 4 827 987 Korean individuals without prior AF, who received biennial health checkups provided by the National Health Insurance Service between 2009 and 2012 in Korea, were analyzed. Incidence of AF was ascertained through the end of 2018. During a median follow‐up of 8.1 years, the annual incidence rate of AF was 1.17 per 1000 person‐years among subjects without CKD, 1.55 for stage 1 CKD, 1.86 for stage 2 CKD, 2.1 for stage 3 CKD, and 4.33 for stage 4 CKD. In Fine‐Gray regression models, CKD was associated with an increased risk of AF; the adjusted hazard ratios and 95% CIs of AF occurrence were 1.77 (1.69–1.85), 1.85 (1.80–1.91), 1.99 (1.95–2.04), and 4.04 (3.07–5.33) in individuals with CKD stages 1, 2, 3, and 4, respectively, compared with non‐CKD. The association between CKD and incident AF remained statistically significant after adjustment for multiple confounding factors and was consistent across subgroups stratified by sex and age. Conclusions: CKD is associated with an increased incidence of AF. Even mild CKD is associated with incident AF, and there was a stepwise increase in the risk of incident AF with a decrease in renal function.

Kook-Hwan Oh, Minjung Kang, Eunjeong Kang, Hyunjin Ryu, Seung Hyeok Han, Tae-Hyun Yoo, Soo Wan Kim, Dong-Wan Chae, Kyu-Beck Lee, Sue K. Park, Yeong Hoon Kim, Curie Ahn, for the KNOW-CKD Study Investigators. Kidney Research and Clinical Practice 2020;39:121-35. https://doi.org/10.23876/j.krcp.20.042

Kang E, et al. J Korean Med Sci. 2017 Feb;32(2):221-230. https://doi.org/10.3346/jkms.2017.32.2.221

Background: Acute kidney injury (AKI) is a critical issue in cancer patients because it is not only a morbid complication but also able to interrupt timely diagnostic evaluation or planned optimal treatment. However, the impact of AKI on overall mortality in cancer patients remains unclear.Methods: We conducted a retrospective cohort study of 67 986 cancer patients, from 2004 to 2013 to evaluate the relationship between AKI and all‐cause mortality. We used KDIGO AKI definition and grading system.Results: During 3.9 ± 3.1 years of follow‐up, 33.8% of the patients experienced AKI at least once. Among AKI events, stage 1, 2, and 3 was 71.0%, 13.8%, and 15.1%, respectively. AKI incidence was highest in hematologic malignancies, followed by urinary tract cancer, and hepatocellular carcinoma. Male sex, older age, underlying diabetes and hypertension, lower serum albumin and plasma hemoglobin, more frequent radio‐contrast exposure, entrance of clinical trials, and receiving chemotherapy were associated with AKI occurrence. AKI development was an independent risk factor for elevated mortality in cancer patients with dose‐responsive manner (Stage 1, hazard ratio [HR] 1.183, 95% confidence interval [CI] 1.145‐1.221, P < 0.001; Stage 2, HR 1.710, 95% CI 1.629‐1.796; Stage 3, HR 2.000, 95% CI 1.910‐2.095; No AKI, reference group) even after adjustment. This tendency was reproduced in various cancer types except thyroid cancer and in various treatment modalities, however, not shown in patients with baseline renal dysfunction.Conclusion: AKI was an independent risk factor for all‐cause mortality in overall cancer patients with dose‐responsive manner.

Objective.: To explain the clinical effect of serum uric acid (SUA) levels as a risk factor for mortality, considering exclusion of kidney function.Methods.: Participants aged over 40 years who underwent health checkups were recruited. Individuals with estimated glomerular filtrations rates < 60 ml/min/1.73 m²and who received laboratory study and colonoscopy on the same day were excluded.Results.: SUA levels were higher in men than in women (5.7 ± 1.2 mg/dl for men and 4.2 ± 0.9 mg/dl for women, p < 0.001). During 12.3 ± 3.6 years of followup, 1402 deaths occurred among 27,490 participants. About 6.9% of men and 3.1% of women died. The overall mortality rate had a U-shaped association with SUA levels, a U-shaped association in men, and no association in women. There was a significant interaction of sex for the SUA-mortality association (p for interaction = 0.049); therefore, survival analysis was conducted by sex. In men, the lower SUA group had a higher mortality rate after adjustment (SUA ≤ 4.0 mg/dl, adjusted HR 1.413, 95% CI 1.158–1.724, p = 0.001) compared with the reference group (SUA 4.1–6.0 mg/dl). A higher SUA contributed to an insignificant increased mortality in men (> 8.0 mg/dl, adjusted HR 1.140, 95% CI 0.794–1.636, p = 0.479). Women failed to show any significant association between SUA and mortality.Conclusion.: This study provided novel evidence that SUA-mortality association differed by sex. We demonstrated that a lower SUA was an independent risk factor for all-cause mortality in men with normal kidney function.

Background: Few studies have examined the association between the early diastolic mitral inflow velocity/early diastolic mitral annulus velocity ratio (E/e’) and chronic kidney disease progression. Methods and Results: We reviewed data from 2238 patients with nondialysis chronic kidney disease from the KNOW‐CKD (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease); data from 163 patients were excluded because of missing content. A >50% decrease in estimated glomerular filtration rate from baseline, doubling of serum creatinine, or dialysis initiation and/or kidney transplantation were considered renal events. At baseline, median (interquartile range) ejection fraction and E/e’ were 64.0% (60.0%–68.0%) and 9.1 (7.4–11.9), respectively. Proportions of ejection fraction <50% and E/e’ ≥15 were 1.3% and 9.6%, respectively. More than one quarter of patients (27.2%) had an estimated glomerular filtration rate <30 mL/min per 1.73 m ² . During the mean 59.1‐month follow‐up period, 724 patients (34.9%) experienced renal events. In multivariable Cox proportional hazard regression analysis, the hazard ratio with 95% CI per 1‐unit increase in E/e’ was 1.027 (1.005–1.050; P =0.016). Penalized spline curve analysis yielded a suggested threshold of E/e’ for renal events of 12; in our data set, the proportion of E/e’ ≥12 was 4.1%. Conclusions: Increased E/e’ was associated with an increased hazard of renal events, suggesting that diastolic heart dysfunction is a novel risk factor for chronic kidney disease progression.