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Rationale & Objective: Both hypo- and hyperkalemia can cause fatal cardiac arrhythmias. Although predialysis serum potassium level is a known modifiable risk factor for death in patients receiving hemodialysis, especially for hypokalemia, this risk may be underestimated. Therefore, we investigated the relationship between predialysis serum potassium level and death in incident hemodialysis patients and whether there is an optimum level. Study Design: Prospective multicenter cohort study. Setting & Participants: 1,117 incident hemodialysis patients (aged >18 years) from the Netherlands Cooperative Study on the Adequacy of Dialysis-2 study were included and followed from their first hemodialysis treatment until death, transplantation, switch to peritoneal dialysis, or a maximum of 10 years. Exposure: Predialysis serum potassium levels were obtained every 6 months and divided into 6 categories: ≤4.0 mmol/L, >4.0 mmol/L to ≤4.5 mmol/L, >4.5 mmol/L to ≤5.0 mmol/L, >5.0 mmol/L to ≤5.5 mmol/L (reference), >5.5 mmol/L to ≤6.0 mmol/L, and >6.0 mmol/L. Outcomes: 6-month all-cause mortality. Analytical Approach: Cox proportional hazards and restricted cubic spline analyses with time-dependent predialysis serum potassium levels were used to calculate the adjusted HRs for death. Results: At baseline, the mean age of the patients was 63 years (standard deviation, 14 years), 58% were men, 26% smoked, 24% had diabetes, 32% had cardiovascular disease, the mean serum potassium level was 5.0 mmol/L (standard deviation, 0.8 mmol/L), 7% had a low subjective global assessment score, and the median residual kidney function was 3.5 mL/min/1.73 m2 (IQR, 1.4-4.8 mL/min/1.73 m2). During the 10-year follow-up, 555 (50%) deaths were observed. Multivariable adjusted HRs for death according to the 6 potassium categories were as follows: 1.42 (95% CI, 1.01-1.99), 1.09 (95% CI, 0.82-1.45), 1.21 (95% CI, 0.94-1.56), 1 (reference), 0.95 (95% CI, 0.71-1.28), and 1.32 (95% CI, 0.97-1.81). Limitations: Shorter intervals between potassium measurements would have allowed for more precise mortality risk estimations. Conclusions: We found a U-shaped relationship between serum potassium level and death in incident hemodialysis patients. A low predialysis serum potassium level was associated with a 1.4-fold stronger risk of death than the optimal level of approximately 5.1 mmol/L. These results may imply the cautious use of potassium-lowering therapy and a potassium-restricted diet in patients receiving hemodialysis.

Background. The epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) varies considerably worldwide, but we have lacked reliable quantitative estimates of trends in the incidence by age, sex and cause in Europe over the last decade. Methods. We analysed data from nine countries participating in the ERA-EDTA registry: Austria, Belgium, Denmark, Finland, Greece, The Netherlands, Norway, Spain and UK (Scotland). Adjusted incidence rates for age and sex were studied for 2 year periods between 1990 and 1999. Average annual changes (%) were estimated by Poisson regression. Results. The adjusted incidence rate of RRT increased from 79.4 per million population (pmp) (range: 58.4-101.0) in 1990-1991 to 117.1 pmp (91.6-144.8) in 1998-1999, i.e. 4.8% (3.1-6.4%) each year. This increase did not flatten out at the end of the decade, except in The Netherlands, and was greater in men than women, 5.2 vs 4.0%/year. In most countries, the incidence rate remained stable for those younger than 45 years; it rose by 2.2%/year on average in the 45-64 year age group and by 7.0% among those 65-74 years; it tripled over the decade in those 75 years or older, and by 1998-1999 it ranged from 140.9 to 540.4 pmp between countries. The incidence of ESRD due to diabetes, hypertension and renal vascular disease nearly doubled over 10 years; in 1998-1999, it varied between countries from 10.2 to 39.3 pmp for diabetes, from 5.8 to 21.0 for hypertension, and from 1.0 to 15.5 for renal vascular disease. Conclusion. RRT incidence continues to rise but at various rates in the European countries studied, tending to widen the gap between them. This mainly results from enlarging differences in incidence in the elderly and, to a lesser extent, in that due to diabetes, hypertension and renal vascular disease. [ABSTRACT FROM AUTHOR]