Serum potassium and outcomes in CKD: insights from the RRI-CKD cohort study.
ABSTRACT The relationship between serum potassium (S(K)) and mortality in chronic kidney disease (CKD) has not been systematically investigated.
We examined the predictors and mortality association of S(K) in the Renal Research Institute CKD Study cohort, wherein 820 patients with CKD were prospectively followed at four US centers for an average of 2.6 years. Predictors of S(K) were investigated using linear and repeated measures regression models. Associations between S(K) and mortality, the outcomes of ESRD, and cardiovascular events in time-dependent Cox models were examined.
The mean age was 60.5 years, 80% were white, 90% had hypertension, 36% had diabetes, the average estimated GFR was 25.4 ml/min per 1.73 m(2), and mean baseline S(K) was 4.6 mmol/L. Higher S(K) was associated with male gender, lower estimated GFR and serum bicarbonate, absence of diuretic and calcium channel blocker use, diabetes, and use of angiotensin-converting enzyme inhibitors and/or statins. A U-shaped relationship between S(K) and mortality was observed, with mortality risk significantly greater at S(K) < or = 4.0 mmol/L compared with 4.0 to 5.5 mmol/L. Risk for ESRD was elevated at S(K) < or = 4 mmol/L in S(K) categorical models. Only the composite of cardiovascular events or death as an outcome was associated with higher S(K) (> or = 5.5).
Although clinical practice usually emphasizes greater attention to elevated S(K) in the setting of CKD, our results suggest that patients who have CKD and low or even low-normal S(K) are at higher risk for dying than those with mild to moderate hyperkalemia.
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ABSTRACT: In the chronic kidney disease (CKD) population, the impact of serum potassium (sK) on renal outcomes has been controversial. Moreover, the reasons for the potential prognostic value of hypokalemia have not been elucidated. 2500 participants with CKD stage 1-4 in the Integrated CKD care program Kaohsiung for delaying Dialysis (ICKD) prospective observational study were analyzed and followed up for 2.7 years. Generalized additive model was fitted to determine the cutpoints and the U-shape association between sK and end-stage renal disease (ESRD). sK was classified into five groups with the cutpoints of 3.5, 4, 4.5 and 5 mEq/L. Cox proportional hazard regression models predicting the outcomes were used. The mean age was 62.4 years, mean sK level was 4.2±0.5 mEq/L and average eGFR was 40.6 ml/min per 1.73 m(2). Female vs male, diuretic use vs. non-use, hypertension, higher eGFR, bicarbonate, CRP and hemoglobin levels significantly correlated with hypokalemia. In patients with lower sK, nephrotic range proteinuria, and hypoalbuminemia were more prevalent but the use of RAS (renin-angiotensin system) inhibitors was less frequent. Hypokalemia was significantly associated with ESRD with hazard ratios (HRs) of 1.82 (95% CI, 1.03-3.22) in sK <3.5mEq/L and 1.67 (95% CI,1.19-2.35) in sK = 3.5-4 mEq/L, respectively, compared with sK = 4.5-5 mEq/L. Hyperkalemia defined as sK >5 mEq/L conferred 1.6-fold (95% CI,1.09-2.34) increased risk of ESRD compared with sK = 4.5-5 mEq/L. Hypokalemia was also associated with rapid decline of renal function defined as eGFR slope below 20% of the distribution range. In conclusion, both hypokalemia and hyperkalemia are associated with increased risk of ESRD in CKD population. Hypokalemia is related to increased use of diuretics, decreased use of RAS blockade and malnutrition, all of which may impose additive deleterious effects on renal outcomes.PLoS ONE 01/2013; 8(7):e67140. · 3.73 Impact Factor
Article: Diuretic use in renal disease.[show abstract] [hide abstract]
ABSTRACT: Diuretics are agents commonly used in diseases characterized by excess extracellular fluid, including chronic kidney disease, the nephrotic syndrome, cirrhosis and heart failure. Multiple diuretic classes, including thiazide-type diuretics, loop diuretics and K(+)-sparing diuretics, are used to treat patients with these diseases, either individually or as combination therapies. An understanding of what determines a patient's response to a diuretic is a prerequisite to the correct use of these drugs. The response of patients with these diseases to diuretics, which is related to the dose, is best described by a sigmoid curve whose contour can become distorted by any of the several sodium-retaining states that are directly or indirectly associated with renal disease. Diuretic actions are of considerable importance to patients who have renal disease, as their effective use assists in extracellular fluid volume control, reducing excretion of protein in urine and lessening the risk of developing hyperkalemia. Diuretic-related adverse events that involve the uric acid, Na(+) and K(+) axes are not uncommon; therefore the clinician must be vigilant in looking for biochemical disturbances. As a result of diuretic-related adverse events, clinicians must be resourceful in the dose amount and frequency of dosing.Nature Reviews Nephrology 12/2011; 8(2):100-9. · 7.94 Impact Factor
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ABSTRACT: Nearly ten years ago, practice recommendations supported use of the clinical classification of 'prehypertension' for people with systolic blood pressure of 120-139 mm Hg or diastolic pressure of 80-89 mm Hg. This recommendation was based on observations that these ranges of blood pressure were associated with enhanced cardiovascular and cerebrovascular risks compared with blood pressure less than 120/80 mm Hg. Recent observations, including the report by Yano and colleagues, also suggest that prehypertension is an important risk factor for the development of chronic kidney disease.Kidney International 02/2012; 81(3):229-32. · 7.92 Impact Factor