Abstract: TH-PO1103

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

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
  • Palaka, Eirini, Health Economics and Outcomes Research, AstraZeneca, Cambridge, United Kingdom
  • Grandy, Susan, Health Economics and Outcomes Research, AstraZeneca, Gaithersburg, Maryland, United States
Background

Renin-angiotensin-aldosterone system inhibitors (RAASi) may be prescribed to CKD patients, but discontinued or dose reduced due to concerns about hyperkalemia (HK). The real-world usage of RAASi was evaluated in UK CKD patients with a range of serum potassium (K+) levels and severities of renal dysfunction.

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 CKD stage 3 or higher 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 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 adjusting for demographic and clinical covariates, including eGFR.

Results

Of the total CKD population at baseline (n=144,388), 37.6% were taking angiotensin-converting enzyme inhibitors, 14.7% were taking angiotensin-II receptor blockers, 2.4% were taking mineralocorticoid receptor antagonists, and 0.04% were taking renin inhibitors. A total of 53,587 RAASi discontinuations were estimated in 704,830 patient-years of follow-up. A J-shaped association between adjusted IRRs and serum K+ was observed, with high serum K+ (≥6.0 mEq/L) being strongly associated with incidence of discontinuation (Figure). This pattern was consistent across eGFR strata. Serum K+ ≥5.5 mEq/L was associated with increased odds of dose reduction (OR=2.24, p<0.001) versus Serum K+ < 5.5 mEq/L.

Conclusion

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

Funding

  • Commercial Support