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Kidney Week

Abstract: PO1450

Relationships Between CKD Duration, Serum Potassium Level, and Adverse Outcomes

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

  • 902 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

  • Tafesse, Eskinder, Global Health Economics, AstraZeneca, Gaithersburg, Maryland, United States
  • James, Glen, Global Medical Affairs, AstraZeneca, Cambridge, United Kingdom
  • Hurst, Michael A., Health Economics and Outcomes Research Ltd, Cardiff, United Kingdom
  • Hoskin, Louise, Health Economics and Outcomes Research Ltd, Cardiff, United Kingdom
  • Badora, Karolina, Health Economics and Outcomes Research Ltd, Cardiff, United Kingdom
  • Sugrue, Daniel, Health Economics and Outcomes Research Ltd, Cardiff, United Kingdom
  • McEwan, Philip, Health Economics and Outcomes Research Ltd, Cardiff, United Kingdom
Background

Patients with chronic kidney disease (CKD) are at increased risk of hyperkalaemia as the kidneys are important in maintaining potassium homeostasis. This study examined the relationships between CKD duration, serum potassium level (K+) and rates of adverse clinical outcomes.

Methods

This retrospective cohort study used linked primary and secondary care data from that UK Clinical Practice Research Datalink (CPRD) GOLD and Hospital Episode Statistics (HES), respectively. Eligible patients were aged ≥18 years with new or existing CKD stage 3+ (READ code or estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m2 without prior dialysis) between January 2008 and June 2018, or during lookback (2003 to 2007). Index date was 01 January 2008 (prevalent cases) or CKD diagnosis date (incident cases); whichever occurred later.

Adverse outcomes were all-cause mortality (ACM) and major adverse cardiovascular events (MACE), a composite of arrhythmia, heart failure, myocardial infarction, and stroke. Crude incidence rates of ACM and MACE were estimated over follow-up from index date to event or end of follow-up (earliest of death, loss to follow-up or study end) based on 1,000 patient years. Published risk equations for ACM and MACE were refitted with adapted coefficient values to include CKD duration (≤5 and >5 years). Reference category for incidence rate ratios was K+ level 4.5 to <5.0 mmol/L.

Results

Among 297,702 CKD patients, 58.6% were female and mean age was 74.7 years (standard deviation, SD 11.3) at index, with mean follow up of 5.6 years (SD 3.20). Mean eGFR at index was 49.7 mL/min/1.73m2 (SD 11.6). Crude rates of ACM and MACE in patients with CKD duration ≤5 years were 60.8 per 1,000 patient years (95% confidence interval (CI) 60.3-61.3) and 102.6 (95% CI 102.0-103.3). Rates in patients with CKD duration >5 years were 76.3 (95% CI 75.4-77.2) and 127.4 (95% CI 126.2-128.5), respectively. Irrespective of duration of CKD, K+ <4.5 or ≥5.0 mmol/L were associated with increased risk of MACE/ACM in comparison with 4.5 to <5.0 mmol/L.

Conclusion

CKD patients with K+ outside the normal range are at increased risk of ACM and MACE, irrespective of CKD duration. Improved management of K+ may reduce adverse clinical outcomes in these patients.

Funding

  • Commercial Support