Potassium binders for chronic hyperkalaemia in people with chronic kidney disease.

BACKGROUND: Hyperkalaemia is a common electrolyte abnormality caused by reduced renal potassium excretion in patients with chronic kidney diseases (CKD). Potassium binders, such as sodium polystyrene sulfonate and calcium polystyrene sulfonate, are widely used but may lead to constipation and other adverse gastrointestinal (GI) symptoms, reducing their tolerability. Patiromer and sodium zirconium cyclosilicate are newer ion exchange resins for treatment of hyperkalaemia which may cause fewer GI side-effects. Although more recent studies are focusing on clinically-relevant endpoints such as cardiac complications or death, the evidence on safety is still limited. Given the recent expansion in the available treatment options, it is appropriate to review the evidence of effectiveness and tolerability of all potassium exchange resins among people with CKD, with the aim to provide guidance to consumers, practitioners, and policy-makers. OBJECTIVES: To assess the benefits and harms of potassium binders for treating chronic hyperkalaemia among adults and children with CKD. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 10 March 2020 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-randomised controlled studies (quasi-RCTs) evaluating potassium binders for chronic hyperkalaemia administered in adults and children with CKD. DATA COLLECTION AND ANALYSIS: Two authors independently assessed risks of bias and extracted data. Treatment estimates were summarised by random effects meta-analysis and expressed as relative risk (RR) or mean difference (MD), with 95% confidence interval (CI). Evidence certainty was assessed using GRADE processes. MAIN RESULTS: Fifteen studies, randomising 1849 adult participants were eligible for inclusion. Twelve studies involved participants with CKD (stages 1 to 5) not requiring dialysis and three studies were among participants treated with haemodialysis. Potassium binders included calcium polystyrene sulfonate, sodium polystyrene sulfonate, patiromer, and sodium zirconium cyclosilicate. A range of routes, doses, and timing of drug administration were used. Study duration varied from 12 hours to 52 weeks (median 4 weeks). Three were cross-over studies. The mean study age ranged from 53.1 years to 73 years. No studies evaluated treatment in children. Some studies had methodological domains that were at high or unclear risks of bias, leading to low certainty in the results. Studies were not designed to measure treatment effects on cardiac arrhythmias or major GI symptoms. Ten studies (1367 randomised participants) compared a potassium binder to placebo. The certainty of the evidence was low for all outcomes. We categorised treatments in newer agents (patiromer or sodium zirconium cyclosilicate) and older agents (calcium polystyrene sulfonate and sodium polystyrene sulfonate). Patiromer or sodium zirconium cyclosilicate may make little or no difference to death (any cause) (4 studies, 688 participants: RR 0.69, 95% CI 0.11, 4.32; I2 = 0%; low certainty evidence) in CKD. The treatment effect of older potassium binders on death (any cause) was unknown. One cardiovascular death was reported with potassium binder in one study, showing that there was no difference between patiromer or sodium zirconium cyclosilicate and placebo for cardiovascular death in CKD and HD. There was no evidence of a difference between patiromer or sodium zirconium cyclosilicate and placebo for health-related quality of life (HRQoL) at the end of treatment (one study) in CKD or HD. Potassium binders had uncertain effects on nausea (3 studies, 229 participants: RR 2.10, 95% CI 0.65, 6.78; I2 = 0%; low certainty evidence), diarrhoea (5 studies, 720 participants: RR 0.84, 95% CI 0.47, 1.48; I2 = 0%; low certainty evidence), and vomiting (2 studies, 122 participants: RR 1.72, 95% CI 0.35 to 8.51; I2 = 0%; low certainty evidence) in CKD. Potassium binders may lower serum potassium levels (at the end of treatment) (3 studies, 277 participants: MD -0.62 mEq/L, 95% CI -0.97, -0.27; I2 = 92%; low certainty evidence) in CKD and HD. Potassium binders had uncertain effects on constipation (4 studies, 425 participants: RR 1.58, 95% CI 0.71, 3.52; I2 = 0%; low certainty evidence) in CKD. Potassium binders may decrease systolic blood pressure (BP) (2 studies, 369 participants: MD -3.73 mmHg, 95%CI -6.64 to -0.83; I2 = 79%; low certainty evidence) and diastolic BP (one study) at the end of the treatment. No study reported outcome data for cardiac arrhythmias or major GI events. Calcium polystyrene sulfonate may make little or no difference to serum potassium levels at end of treatment, compared to sodium polystyrene sulfonate (2 studies, 117 participants: MD 0.38 mEq/L, 95% CI -0.03 to 0.79; I2 = 42%, low certainty evidence). There was no evidence of a difference in systolic BP (one study), diastolic BP (one study), or constipation (one study) between calcium polystyrene sulfonate and sodium polystyrene sulfonate. There was no difference between high-dose and low-dose patiromer for death (sudden death) (one study), stroke (one study), myocardial infarction (one study), or constipation (one study). The comparative effects whether potassium binders were administered with or without food, laxatives, or sorbitol, were very uncertain with insufficient data to perform meta-analysis. AUTHORS' CONCLUSIONS: Evidence supporting clinical decision-making for different potassium binders to treat chronic hyperkalaemia in adults with CKD is of low certainty; no studies were identified in children. Available studies have not been designed to measure treatment effects on clinical outcomes such as cardiac arrhythmias or major GI symptoms. This review suggests the need for a large, adequately powered study of potassium binders versus placebo that assesses clinical outcomes of relevance to patients, clinicians and policy-makers. This data could be used to assess cost-effectiveness, given the lack of definitive studies and the clinical importance of potassium binders for chronic hyperkalaemia in people with CKD.

Acute and chronic cardiovascular effects of hyperkalemia: new insights into prevention and clinical management.

The plasma pool of potassium is a partial reflection of the overall body, transient cellular shifts, and potassium elimination regulated by the kidneys. Potassium concentrations elevating above the upper limit of normal (> 5.0 mEq/L) have become more common in cardiovascular practice due to the growing population of patients with chronic kidney disease and the broad applications of drugs that modulate potassium excretion by either reducing production of angiotensin II (angiotensin-converting enzyme inhibitors, direct renin inhibitors, beta-adrenergic receptor antagonists), blocking angiotensin II receptors (angiotensin receptor blockers), or antagonizing the action of aldosterone on mineralocorticoid receptors (mineralocorticoid receptor antagonists). In addition, acute kidney injury, critical illness, crush injuries, and massive red blood cell transfusions can result in hyperkalemia. Progressively more severe elevations in potassium are responsible for abnormalities in cardiac depolarization and repolarization and contractility. Untreated severe hyperkalemia results in sudden cardiac death. Traditional management steps have included reducing dietary potassium and discontinuing potassium supplements; withdrawal of exacerbating drugs; acute treatment with intravenous calcium gluconate, insulin, and glucose; nebulized albuterol; correction of acidosis with sodium bicarbonate for short-term shifts out of the plasma pool; and, finally, gastrointestinal ion exchange with oral sodium polystyrene sulfonate in sorbitol, which is mainly used in the hospital and is poorly tolerated due to gastrointestinal adverse effects. This review explores hyperkalemia as a complication in cardiovascular patients and highlights new acute, chronic, and preventative oral therapies (patiromer calcium, cross-linked polyelectrolyte, ZS-9) that could potentially create a greater margin of safety for vulnerable patients with combined heart and kidney disease.

Glucose and insulin infusion versus kayexalate for the early treatment of non-oliguric hyperkalemia in very-low-birth-weight infants.

Forty very low birth weight (VLBW) infants with non-oliguric hyperkalemia in the first few days after birth were enrolled in this study. They were randomly divided into 2 groups, regular insulin (RI) infusion group and kayexalate resin enema group. Therapy was administered when serum potassium level was greater than 6 mEq/L. None of these infants received blood transfusion during this study course. In RI group (n = 20), the ratio of infusion glucose to regular insulin was 10-15 gm glucose to 1 unit RI, and the glucose infusion rate was maintained at least 6 mg/Kg/min. In Kayexalate group (n = 20), the dose of Kayexalate was 1 gm/Kg body weight given rectally every four hours. All treatment discontinued after the serum potassium level returned to normal for 6 hours. The mean gestational ages were 27.4 +/- 1.8 weeks in RI group and 28.4 +/- 2.4 weeks in Kayexalate group, respectively. Mean birth weights were 935 +/- 259 gm (RI) and 1065 +/- 214 gm (Kayexalate). The ages at onset of hyperkalemia were 24.6 +/- 8.2 (RI) and 22.2 +/- 8.1 (Kayexalate) hours after birth. The mean urine outputs during the 8-hour interval prior to development of hyperkalemia were 5.4 +/- 1.3 (RI) and 5.5 +/- 0.9 (Kayexalate) ml/kg/min. The durations of hyperkalemia were 26.4 +/- 14.9 (RI) and 38.6 +/- 13.3 (Kayexalate) hours. The peak serum potassium levels during therapy were 7.3 +/- 0.9 and 7.4 +/- 0.6 mEq/L. The incidences of grade II and above intraventricular hemorrhage (IVH) were 15% (3/20) and 50% (10/20). The incidences of cardiac dysrhythmia were 5% (1/20) and 10% (2/20). Significantly shorter duration of non-oliguric hyperkalemia and lower incidence of IVH were noted in RI group, but there were no differences in the peak potassium level or the incidence of cardiac dysrhythmia between these two groups. We conclude that to use early continuous regular insulin infusion therapy for the treatment of non-oliguric hyperkalemia in VLBW infants is more effective than kayexalate in decreasing the duration of hyperkalemia and reducing the incidence of intraventricular hemorrhage.

Hyperkalaemia in patients in hospital.

A survey of all laboratory blood specimens with a plasma potassium concentration greater than or equal to 5.5 mmol/L was conducted over a three month period. Of 331 specimens with hyperkalaemia, 71 were excluded because the specimens was haemolysed, old or contaminated. The laboratory served a population of 348,561 and during this time measured the plasma potassium on 25,016 occasions. Sixty-six outpatients and 20 neonates were not evaluated. The survey was undertaken on 86 of 102 inpatients (46 males), 48 of whom were over 66 years of age. Fifty-seven patients were admitted under a medical service and 29 under a surgical service. Fifty-nine had a single episode of hyperkalaemia. Thirty-two underwent a surgical procedure. The commonest contributing factor was impaired renal function which was present in 71 (83%) patients. Although a definitive causative role for drugs could be identified in only five patients, in 52 (60%) patients drugs were a contributing factor (potassium supplements 24, ACE inhibitors 16, nonsteroidal antiinflammatory drugs 12). Thirty-five of the 86 (41%) patients died during their hospital admission. Nineteen of the 35 deaths occurred within three days of the hyperkalaemia being recorded. A normal plasma potassium was eventually documented in 50 of the 86 patients. Of the remaining 36 patients, 25 (69%) subsequently died. In general the treatment of patients with hyperkalaemia focused on identifying and treating the underlying cause. Hyperkalaemia must always be considered seriously and regard given to the overall clinical status of the patient, with particular attention to drug therapy, renal and cardiac function, acid base status and the possibility of sepsis.