Abstract: TH-PO1102

Relationship between Serum Potassium and Dose Modification and Discontinuation of Renin-Angiotensin-Aldosterone System Inhibitors in UK Patients with Heart Failure

Session Information

Category: Fluid, Electrolytes, and Acid-Base

  • 704 Fluid, Electrolyte, Acid-Base Disorders

Authors

  • Qin, Lei, Health Economics and Outcomes Research, AstraZeneca, Gaithersburg, Maryland, United States
  • McEwan, Philip, Centre for Health Economics, Swansea University, Singleton Park, United Kingdom
  • Evans, Marc Lyndon, Department of Medicine, University Hospital Llandough, Cardiff, United Kingdom
  • Horne, Laura, Global Medical Affairs, AstraZeneca, Gaithersburg, Maryland, United States
  • Grandy, Susan, Health Economics and Outcomes Research, AstraZeneca, Gaithersburg, Maryland, United States
Background

Renin-angiotensin-aldosterone system inhibitors (RAASi) may be prescribed to heart failure (HF) patients, but discontinued due to concerns over hyperkalemia (HK). The real-world usage of RAASi in primary care was evaluated in UK HF patients with a range of serum potassium (K+) levels.

Methods

A retrospective observational study was conducted using primary care data from the Clinical Practice Research Datalink from Jan 2006 to Dec 2015. Patients (≥18 years) were included if they had a first diagnosis of HF during the study period. RAASi discontinuation was defined as a ≥90-day gap without a prescription using the medicines possession ratio, and dose reduction as a decrease to prescribed daily dose between successive prescriptions. Incidence rate ratios (IRRs) for discontinuation and odds of dose reduction were tested for association with time-updated serum K+ using Poisson and Logistic Generalized Estimating Equations respectively after adjustment for demographic and clinical covariates.

Results

Of the total HF population at baseline (n=23,541), 60.9%, 15.1%, 23.4% and 0.04% were taking angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, mineralocorticoid receptor antagonists and renin inhibitors, respectively. A total of 7,527 RAASi discontinuations were estimated in 68,133 patient-years of follow-up, a reference rate of 110 discontinuations per thousand patient-years. A J-shaped association between adjusted IRRs and serum K+ was observed, with high serum K+ (≥6.0 mEq/L) being strongly associated (p<0.001) with incidence of discontinuation (Figure). Serum K+ ≥5.5 mEq/L was associated with an increased odds of dose reduction (OR=1.33, p=0.035) versus Serum K+ < 5.5 mEq/L.

Conclusion

Physicians were more likely to discontinue RAASi or reduce dose in HF patients with HK. Further research is warranted to determine the clinical impact of RAASi dose modification and discontinuation in the treatment of HK in the UK.

Funding

  • Commercial Support