Chronic Hyperkaliemia in Chronic Kidney Disease: An Old Concern with New Answers.

Increasing potassium intake ameliorates blood pressure (BP) and cardiovascular (CV) prognoses in the general population; therefore the World Health Organization recommends a high-potassium diet (90-120 mEq/day). Hyperkalaemia is a rare condition in healthy individuals due to the ability of the kidneys to effectively excrete dietary potassium load in urine, while an increase in serum K+ is prevalent in patients with chronic kidney disease (CKD). Hyperkalaemia prevalence increases in more advanced CKD stages, and is associated with a poor prognosis. This scenario generates controversy on the correct nutritional approach to hyperkalaemia in CKD patients, considering the unproven link between potassium intake and serum K+ levels. Another concern is that drug-induced hyperkalaemia leads to the down-titration or withdrawal of renin-angiotensin system inhibitors (RASI) and mineralocorticoids receptors antagonists (MRA) in patients with CKD, depriving these patients of central therapeutic interventions aimed at delaying CKD progression and decreasing CV mortality. The new K+-binder drugs (Patiromer and Sodium-Zirconium Cyclosilicate) have proven to be adequate and safe therapeutic options to control serum K+ in CKD patients, enabling RASI and MRA therapy, and possibly, a more liberal intake of fruit and vegetables.

Prevalence and renal prognosis of left ventricular diastolic dysfunction in non-dialysis chronic kidney disease patients with preserved systolic function.

BACKGROUND: Left ventricular (LV) diastolic dysfunction is common in non-dialysis chronic kidney disease (ND-CKD) patients; however, the prevalence estimated according to the new diagnostic criteria as well as the prognostic role of diastolic dysfunction on CKD progression remain unknown. METHOD: We longitudinally evaluated consecutive ND-CKD patients and preserved systolic function (LV ejection fraction > 50%). According to the recently updated guidelines, LV diastolic dysfunction was assessed by four echocardiographic variables (annular e' velocity, average mitral valve E-wave/e' ratio, left atrial volume index and tricuspid regurgitation). Patients were classified as diastolic dysfunction, indeterminate and normal. Time-dependent estimated glomerular filtration rate (eGFR) change was assessed by mixed-effects regression model. Cumulative incidence of composite renal outcome (eGFR decline > 50% or chronic dialysis) was also estimated. RESULTS: Among 140 patients (age 66.2 ±â€Š14.5 years; 61% males; eGFR 39.8 ±â€Š21.8 ml/min per 1.73m2; 43.6% diabetics), diastolic dysfunction occurred in 22.9%, indeterminate in 45.7% and normal in 31.4%. Prevalence of diastolic dysfunction was much lower than that estimated with older criteria (62.7%). Logistic regression (odds ratio, 95% confidence interval [CI]) showed that diastolic dysfunction was associated with lower eGFR (0.97, 0.94-0.99), older age (1.04, 1.01-1.06) and night-time systolic blood pressure (1.04, 1.00-1.07). Across 1702 eGFR measurements collected during a median follow-up of 4.6 years, eGFR decline (ml/min per 1.73m2; per year) was faster in patients with diastolic dysfunction (-2.12, 95% CI from -2.68 to -1.56) and in the indeterminate (11.2/100 pts per year) as compared to normal (-1.14, 95% CI from -1.64 to -0.63). Incidence of composite renal outcome was significantly higher in diastolic dysfunction (13.8/100 pts/year) than in normal group (3.5/100 pts per year)'. CONCLUSION: In ND-CKD population, LV diastolic dysfunction is less frequent than previously described and acts as independent predictor of CKD progression.