Date of publication: January 31, 2017

News & Views

ASN Kidney Week 2016: New Epidemiology Data and Treatment Options for Hyperkalemia

The annual ASN Kidney Week Congress was held in Chicago last year, providing the platform for presentation and discussion of the latest research from across the field of nephrology. This article brings you a summary of the conference highlights relating to hyperkalemia, so if you couldn’t make it to Chicago, or didn’t have time to catch it all, you can keep up-to-date here.

New prevalence data for hyperkalaemia

Two posters were presented during the Friday session that examined the prevalence of hyperkalemia (HK).

Woolley et al. used the NHANES (National Health and Nutrition Examination Survey) database to identify rates of HK in the general American population, as well as within groups with certain co-morbidities. They found an overall rate of HK (serum potassium >5.0mEq/L) of 564 per 100,000 in the total population. Prevalence increased with age and certain comorbidities, and was more common in males and in patients taking RAAS inhibitors. The most common comorbidity in adults with HK was chronic kidney disease (CKD) at a rate of 3,479 per 100,000, almost 10 times that in those without CKD. Heart failure was next, with a rate of 3,387 per 100,000.[1]

In a second poster, Dr Keith Betts and colleagues looked specifically at the prevalence of HK within the CKD population in America.[2] Extracting information from a commercial claims database, they reported a prevalence of 2.2%-2.7% among all CKD patients in the years 2010-2014. However, once stratified by CKD stage, prevalence increased from 1% in CKD stage 2 up to 29% – 34% for stage 5 and even 40% – 43% for patients on dialysis.[2]

Hyperkalaemia and the risk of adverse outcomes

Two new analyses looked at the clinical impact of serum potassium levels in different CKD subpopulations.

Using data from the CKD Prognosis Consortium (26 cohorts in total), Dr Kovesdy et al. examined all-cause mortality, cardiovascular mortality, and progression to end-stage renal disease in relation to potassium levels.[3] The mean eGFR of this meta-analysis population was 83 ml/min/1.73m[2]. The lowest risk for all-cause mortality was seen with a potassium level of 4.2mmol/L. Both hypokalaemia (<3.5mmol/L) and HK(>5.5mmol/L) were associated with a higher risk of all-cause mortality compared to the reference level. The relationships of potassium levels with cardiovascular mortality and end-stage renal disease were similar. The authors called for randomised controlled trials to investigate if treatment of abnormal serum potassium levels can lead to improved outcomes.[3]

Dr Melissa Soohoo and colleagues presented an analysis of the association between baseline serum potassium levels and post-haemodialysis hospitalisation rates in veterans with CKD transitioning to dialysis.[4] The mean±SD potassium level of the cohort prior to transition was 4.5±0.6mEq/L. The study found that both low serum potassium (<3.9 mEq/L) and high serum potassium (≥4.7 mEq/L) levels in the 6 months prior to transition to ESRD (End Stage Renal Disease) were associated with lower rates of hospitalisation in the early post-haemodialysis period compared to reference.[4]

Evolving hyperkalaemia treatment options

New data was also presented on two potassium binders. Patiromer is approved for use in the US and is currently under review in Europe. Pooled analysis of Phase II and III trials was presented, investigating any potential interactions between patiromer and common, concomitant antihypertensive therapies (amlodipine, furosemide and metoprolol).[5] Patiromer had been initiated at total daily doses of 8.4-33.6g (divided twice daily), and Dr Matthew Weir and colleagues looked at any changes in systolic or diastolic blood pressure or increases in antihypertensive medication in the four weeks following initiation.[5] The data showed no evidence of any adverse systematic blood pressure effects in patients on common antihypertensive medications following initiation of patiromer.[5]

In another analysis, Dr Weir looked at the effects of patiromer on blood pressure in patients with low plasma renin activity and low aldosterone.[6] Patients were divided into groups:

  • LRA1: aldosterone <5ng/dL, plasma renin activity <1µg/L/h, serum potassium ≥5.1mEq/L
  • LRA2: aldosterone <10ng/dL, plasma renin activity <2µg/L/h, serum potassium ≥5.5mEq/L
  • serum potassium ≥5.1mEq/L and no LRA1
  • serum potassium ≥5.5mEq/L and no LRA2

After four weeks of patiromer treatment, blood pressure and serum potassium had decreased in all groups.[6] Aldosterone did not decrease in LRA1 or LRA2 but did in the other groups, whilst plasma renin activity increased only in LRA1 and LRA2.6 The reduction in blood pressure may be due to both aldosterone reduction and decreased sodium absorption.[6]

Early, 6-month results from the long-term open-label study of the potassium binder sodium zirconium cyclosilicate (ZS-9) were also presented.[7]If patients had achieved normokalaemia during the induction phase of the trial they entered the maintenance phase, when they received ZS-9 5g/d for ≤12months. The mean potassium level remained 4.7mEq/L during this phase. The team concludes that these preliminary results suggest that long-term treatment with ZS-9 can maintain normokalaemia.[7]

Dr Pergola and colleagues presented data from the same trial demonstrating no clinically significant changes in mean systolic or diastolic blood pressure for all patients treated with ZS-9 or those who completed 12 months’ treatment.[8]

References

  1. Abstract: [FR-PO788] Prevalence of Hyperkalemia among U.S. Adults. http://www.abstracts2view.com/asn_2016/view.php?nu=5043&terms=&type=abstract
  2. Abstract: [FR-PO784] Prevalence of Hyperkalemia among Patients with Chronic Kidney Disease. http://www.abstracts2view.com/asn_2016/view.php?nu=1204&terms=&type=abstract
  3. Abstract: [TH-PO475] Serum Potassium and the Risk of Adverse Outcomes: A CKD Prognosis Consortium Meta-Analysis. http://www.abstractcom/asn_2016/view.php?nu=1012&terms=&type=abstract
  4. Abstract: [FR-PO954] Association of 6-Month Pre-ESRD Potassium with Immediate Post-Dialysis Hospitalization among U.S. Veterans: A Transition of Care in CKD Study. http://www.abcom/asn_2016/view.php?nu=3771&terms=&type=abstract
  5. Abstract: [TH-PO480] Evaluation of Potential Pharmacodynamic Interactions with Antihypertensive Drugs Given Concomitantly with Patiromer: Pooled Analysis of Phase 2/3 Clinical Trials. http://www.abstracts2view.com/asn_2016/view.php?nu=3776&terms=&type=abstract
  6. Abstract: [TH-PO479] Aldosterone, Renin and Blood Pressure during Patiromer Treatment of Hyperkalemia in CKD. http://www.abstracts2view.com/asn_2016/view.php?nu=2203&terms=&type=abstract
  7. Abstract: [TH-PO477] Long-Term Sodium Zirconium Cyclosilicate Treatment in Patients with Hyperkalemia: Interim Analysis of an Open-Label Phase 3 Study. http://www.abstracts2view.com/asn_2016/view.php?nu=4694&terms=&type=abstract
  8. Abstract: [TH-PO478] Effect of Sodium Zirconium Cyclosilicate Treatment for Hyperkalemia on Blood Pressure in a Long-Term Open-Label Phase 3 Study. http://www.abstracts2view.com/asn_2016/view.php?nu=4898&terms=&type=abstract

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