From the Journals

Low RAAS inhibitor dosing linked to MACE risk



Suboptimal dosing of renin-angiotensin-aldosterone system (RAAS) inhibitors to reduce the risk of hyperkalemia could increase the risk of major adverse cardiac events (MACE) and all-cause mortality in patients with chronic kidney disease (CKD) or heart failure.


Researchers reported the outcomes of an observational study that explored the real-world associations between RAAS inhibitor dose, hyperkalemia, and clinical outcomes.

RAAS inhibitors – such as ACE inhibitors, angiotensin receptor blockers, and mineralocorticoid receptor antagonists – are known to reduce potassium excretion and therefore increase the risk of high potassium levels.

Dr. Cecilia Linde, from the Karolinska University Hospital and Karolinska Institutet in Stockholm, and coauthors wrote that management of serum potassium levels often requires reducing the dosage of RAAS inhibitors or stopping them altogether. However, this is also associated with risks in patients with heart failure or CKD.

In this study, researchers looked at data from 100,572 people with nondialysis CKD and 13,113 with new-onset heart failure who were prescribed RAAS inhibitors during 2006-2015.

Overall, 58% of patients with CKD and 63% of patients with heart failure spent the majority of follow-up on prescribed optimal doses of RAAS inhibitors – defined as at least 50% of the guidelines-recommended dose.

Patients with hyperkalemia were more likely to have down-titrations or discontinue their RAAS inhibitors, and this increased with increasing hyperkalemia severity.

The study found consistently lower mortality rates among patients who spent most of their follow-up time on at least 50% of the guideline-recommended dose of RAAS inhibitors.

In patients with CKD, mortality rates were 7.2 deaths per 1,000 patient-years in those taking at least 50% of the recommended dose, compared with 57.7 deaths per 1,000 patient-years for those on suboptimal doses. The rates of MACE were 73 and 130 per 1,000 patient-years, respectively.

The differences were even more pronounced in patients with heart failure. Those taking at least 50% of the recommended dose had mortality rates of 12.5 per 1000 patient-years, compared with 141.7 among those on suboptimal doses. The rates of MACE were 148.5 and 290.4, respectively.

“The results highlight the potential negative impact of suboptimal RAASi dosing, indicate the generalizability of [European Society of Cardiology–recommended] RAASi doses in HF to CKD patients, and emphasize the need for strategies that allow patients to be maintained on appropriate therapy, avoiding RAASi dose modification or discontinuation,” the authors wrote.

The study was funded by AstraZeneca. One author was an employee and stockholder of AstraZeneca, and five authors declared funding and support from the pharmaceutical sector, including AstraZeneca.

SOURCE: Linde C et al. J Am Heart Assoc. 2019 Nov 12. doi: 10.1161/JAHA.119.012655.

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