September 15, 2014

LAS VEGAS, NV — A discharge prescription for the aldosterone blocker spironolactone in patients with a low ejection fraction who had been hospitalized for heart failure was not related to their likelihood of readmission within 30 days in a propensity-matched analysis based on a multicenter Medicare population[1]. Nor was it related to 30-day risk of HF readmission or death from any cause.

Spironolactone after a heart-failure discharge apparently does little to help hospitals improve by the controversial metric of 30-day readmission, which the Affordable Care Act tied to their Medicare payments.

It's not that the drug doesn't "work" in heart failure, observed Dr Chakradhari Inampudi (University of Iowa Hospitals and Clinics, Iowa City) for heartwire . "We recognize that spironolactone is a great drug, undoubtedly, but the benefit has been most commonly noted in the randomized trials. That same benefit has not been observed in real-world patient populations."

The issue comes up a lot in practice, he noted. "We would like to use it. I prescribe it in my practice. But we would also like these patients, who have a lot of comorbidities, to get the full beneficial effects of the drug."

Inampudi is lead author on the analysis, presented in a poster here at the Heart Failure Society of America (HFSA) 2014 Scientific Meeting that is based on a cohort of 5479 patients aged >65 years hospitalized with heart failure at 106 hospitals participating in the Alabama Heart Failure Project.

After winnowing the group down to about 1900 patients with LVEF <35%, low serum creatinine (<2.5 mg/dL for men and <2 mg/dL for women), and potassium <5 mEq/L, the researchers created 410 propensity-matched pairs of patients who had been prescribed or not prescribed spironolactone at discharge. Their mean age was 72 years, 24% were women, and 42% were African American.

Whether patients were or were not discharged on the drug depended on prevailing practice patterns, not specific selection of patients for a spironolactone prescription, according to Inampudi.

Hazard Ratio (95% CI) for 30-Day Outcomes, Discharge on Spironolactone vs Not Discharged on Spironolactone

End points HR (95% CI)
All-cause readmission 0.96 (0.70–1.33)
HF readmission 0.90 (0.55–1.47)
All-cause mortality 0.57 (0.30–1.07)
All-cause mortality or readmission 0.85 (0.63–1.15)

Nor did aldosterone blockade affect the same clinical end points at six months or one year, according to Inampudi.

Dr Chakradhari Inampudi

"There's something in the clinical research that isn't translating to the real world," he said. Should physicians be giving higher dosages or doing better at optimizing other heart-failure medications? "All the studies included patients who were already on adequate doses of ACE inhibitors. In clinical practice, it's hard to get up to guideline-directed dosages."

Is it because patients in the clinical trials tended to have few comorbidities, he asked, or that they were monitored for levels of aldosterone and potassium and for renal function to track treatment efficacy and avert adverse effects—something that isn't broadly feasible in clinical practice?

Inampudi proposed that in clinical practice, patients may not usually be tracked long enough to completely gauge the benefits of aldosterone blockade in heart failure, which may depend greatly on reversal of ventricular dilatation and other adverse cardiac remodeling. It may be, he speculated, that longer than 30 days or six months is required for that.

What's needed, and where his group's research is headed, Inampudi said, is development of strategies for improving selection of patients with heart failure who may respond best to aldosterone blockade, how to dose the drug and monitor patients for its effects, beneficial and adverse, and how to reduce the risk of adverse effects so that spironolactone responses in clinical practice become more like those seen in the trials.

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