Introduction: Severe hyperkalemia, with potassium (K⁺) levels ≥ 6.5 mEq/L, is a potentially life-threatening electrolyte imbalance. For prompt and effective treatment, it is important to know its risk factors, clinical manifestations, and predictors of mortality. Methods: An observational cohort study was performed at 2 medical centers. A total of 923 consecutive Korean patients were analyzed. All were 19 years of age or older and were hospitalized with severe hyperkalemia between August 2007 and July 2010; the diagnosis of severe hyperkalemia was made either at the time of admission to the hospital or during the period of hospitalization. Demographic and baseline clinical characteristics at the time of hyperkalemia diagnosis were assessed, and clinical outcomes such as in-hospital mortality were reviewed, using the institutions' electronic medical record systems. Results: Chronic kidney disease (CKD) was the most common underlying medical condition, and the most common precipitating factor of hyperkalemia was metabolic acidosis. Emergent admission was indicated in 68.6% of patients, 36.7% had electrocardiogram findings typical of hyperkalemia, 24.5% had multi-organ failure (MOF) at the time of hyperkalemia diagnosis, and 20.3% were diagnosed with severe hyperkalemia at the time of cardiac arrest. The in-hospital mortality rate was 30.7%; the rate was strongly correlated with the difference between serum K⁺ levels at admission and at their highest point, and with severe medical conditions such as malignancy, infection, and bleeding. Furthermore, a higher in-hospital mortality rate was significantly associated with the presence of cardiac arrest and/or MOF at the time of diagnosis, emergent admission, and intensive care unit treatment during hospitalization. More importantly, acute kidney injury (AKI) in patients with normal baseline renal function was a strong predictor of mortality, compared with AKI superimposed on CKD. Conclusions: Severe hyperkalemia occurs in various medical conditions; the precipitating factors are similarly diverse. The mortality rate is especially high in patients with severe underlying disease, coexisting medical conditions, and those with normal baseline renal function.

Ryu SR, et al. J Korean Med Sci. 2017 Feb;32(2):249-256. https://doi.org/10.3346/jkms.2017.32.2.249

Background and objectives: Exposure to environmental chemicals has been recognized as one of the possible contributors to CKD. We aimed to identify environmental chemicals that are associated with CKD. Design, setting, participants, & measurements: We analyzed the data obtained from a total of 46,748 adults who participated in the National Health and Nutrition Examination Survey (1999–2016). Associations of chemicals measured in urine or blood (n=262) with albuminuria (urine albumin-to-creatinine ratio ≥30 mg/g), reduced eGFR (<60 ml/min per 1.73 m²), and a composite of albuminuria or reduced eGFR were tested and validated using the environment-wide association study approach. Results: Among 262 environmental chemicals, seven (3%) chemicals showed significant associations with increased risk of albuminuria, reduced eGFR, or the composite outcome. These chemicals included metals and other chemicals that have not previously been associated with CKD. Serum and urine cotinines, blood 2,5-dimethylfuran (a volatile organic compound), and blood cadmium were associated with albuminuria. Blood lead and cadmium were associated with reduced eGFR. Blood cadmium and lead and three volatile compounds (blood 2,5-dimethylfuran, blood furan, and urinary phenylglyoxylic acid) were associated with the composite outcome. A total of 23 chemicals, including serum perfluorooctanoic acid, seven urinary metals, three urinary arsenics, urinary nitrate and thiocyanate, three urinary polycyclic aromatic hydrocarbons, and seven volatile organic compounds, were associated with lower risks of one or more manifestations of CKD. Conclusions: A number of chemicals were identified as potential risk factors for CKD among the general population.

Hyun YY, et al. J Korean Med Sci. 2017 Feb;32(2):257-263. https://doi.org/10.3346/jkms.2017.32.2.257

The long-term prognosis of clinically early IgA nephropathy (IgAN) patients remains to be clarified. We investigated the long-term outcomes of IgAN patients with an apparently benign presentation and evaluated prognostic factors for renal survival. We included patients with biopsy-proven IgAN who had estimated glomerular filtration rates (eGFR) ≥60 mL/min/1.73 m², normal blood pressure, and proteinuria 1 g/day. The analysis included 153 patients who met the inclusion criteria. At diagnosis, their median systolic blood pressure was 120 (110–130) mmHg, eGFR was 85.9 (74.9–100.1) mL/min/1.73 m², and proteinuria was 0.25 (0.13–0.38) g/day. Of these, 4 patients died and 6 reached ESRD. The 30-year renal survival rate was 85.5%. Three patients had increased serum creatinine levels and 11 developed proteinuria. Remission was observed in 35 (22.9%) patients. A moderate or severe degree of interstitial fibrosis (adjusted odd ratio [OR] 5.93, 95% confidence interval [CI] 1.44–24.45, P = 0.014) and hypoalbuminemia (adjusted OR 6.18, 95% CI 1.20–31.79, P = 0.029) were independent predictors of the secondary outcome. This study showed that the prognosis of early IgAN was not always favorable, even resulting in progression to ESRD in some cases. Hypoalbuminemia and interstitial fibrosis should also be considered important prognostic factors in clinically early IgAN patients.

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