Study on Hyperkalemia in CKD Patients

High serum potassium concentration (HK) is due to impaired renal function and is commonly seen in Chronic Kidney Disease (CKD) patients. A study published in the journal NEPHROLOGY DIALYSIS TRANSPLANTATION on June 06, 2020, suggests that nearly half of the patients with CKD experience hyperkalemia events, and the patients who experience hyperkalemia events are likely to develop recurrent HK events. The study findings were presented at the European Renal Association-European Dialysis and Transplant Association 2020 virtual congress.

Recurrent hyperkalemia is a major cause of hospitalization, especially for patients with chronic kidney disease (CKD) and heart failure. High HK levels are potentially life-threatening if untreated or poorly managed. However, the frequency of recurrent HK and time between events remains unclear. Therefore, researchers of the Health Economics and Outcomes Research Ltd, Cardiff, United Kingdom, conducted a study to describe the characteristics of CKD patients in the UK who experience HK and assessed the frequency of recurrent HK and time between first (index) and subsequent events.

It was a retrospective cohort study, conducted using linked Clinical Practice Research Datalink (CPRD) and Hospital Episode Statistics (HES) data from 01 January 2008 to 30 June 2018, with a five-year lookback period (2003-2007). Researchers included 297,702 patients with CKD stage 3+ (READ code or eGFR <60 mL/min/1.73m² without prior dialysis) during the study or lookback periods and aged >18 years at diagnosis (index). They assessed patient demographics, clinical history, and baseline medication. They determined serum K⁺ ≥5.0 mmol/L as HK events and any event after the first event as a recurrent HK event. They also assessed the HK events occurring during the study period, but after the diagnosis of CKD and calculated the time of recurrence using Kaplan-Meier.

At the time of CKD diagnosis, researchers noted that 30.6% of the population had resistant hypertension, 22.24% had diabetes, 7.9% had CKD, and 7.8% had cancer. They also noted at baseline, 49.2% were on diuretics, while 32.5% and 32.0% were on beta-blockers and calcium channel blockers. During the follow-up, they noted that 67.0% were on renin-angiotensin-aldosterone system inhibitor (RAASi).

Key Findings of the Study

• Upon analysis, researchers found that 49.5% experienced at least one HK event, of which 36.5% had only one HK event, 63.5% had two or more HK events, and 20.0% had six or more events.
• They reported that the HK event incidences were predictive of subsequent events and the probability of experiencing an HK event increased from 49.5% to 63.5%, 70.7%, 74.1%, 76.5%, and 78.6% for the patients experiencing 2-6 events, respectively.
• They noted an inverse relationship between the number of recurrent events and time to the next event, with less time between the next event for those experiencing multiple events.

The authors concluded, "This study shows that approximately half of CKD patients experienced an HK event. Furthermore, patients who experienced an HK event were at increased risk of subsequent events. Frequent monitoring of serum potassium may help reduce the burden of HK in patients with CKD."

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