ORLANDO—Clinicians are less likely to use evidence-based therapies for congestive heart failure (CHF), especially ACE inhibitors or angiotensin receptor blockers (ARBs), when their patients also have renal dysfunction, a study found.
“Renal dysfunction is probably one of the biggest predictors of mortality in heart failure, and we found it is common in outpatients. About half had significant kidney disease, stage 3 or higher, and this affected the use of evidence-based therapies,” said investigator J. Thomas Heywood, MD, Director of the Heart Failure Program at Scripps Clinic in La Jolla, Calif.
In particular, many patients in the study were not receiving ACE inhibitors or ARBs. “For some patients, withholding these agents may be appropriate, but for others it would clearly be inappropriate,” Dr. Heywood noted.
He and his colleagues analyzed data from the quality-improvement program Improve the Use of Evidence-Based Heart Failure Therapies in the Outpatient Setting (IMPROVE HF), which involves 167 cardiology outpatient practices. It is among the first and largest projects to evaluate the “real world” treatment of heart failure, especially adherence to seven evidence-based approaches to management. The researchers presented findings here at the 58th Scientific Session of the American College of Cardiology.
“Ultimately, we hope that with tools of practice improvement, we can use these data to improve outcomes,” Dr. Heywood added.
The study focused on the diagnosis of renal dysfunction among 13,164 CHF patients and its impact on the use of ACE inhibitors and ARBs, beta blockers, aldosterone receptor antagonists, anticoagulation therapy, implantable cardioverter defibrillators, cardiac resynchronization therapy, and heart failure education.
CKD was present in nearly 90% of patients, with 10% having an estimated glomerular filtration rate (eGFR) of 90 mL/min/1.73 m2 or higher (stage 1), 38% with eGFR of 60-89 (stage 2), 44% with eGFR of 30-59 (stage 3), and 8% with eGFR of 29 or less (stage 4/5).
Advanced CKD was most common among patients who were older or female or who had an ischemic heart failure etiology. High-stage CKD was also common among patients with such comorbid conditions as atrial fibrillation or flutter, diabetes, chronic obstructive pulmonary disease, peripheral vascular disease, and prior coronary artery bypass graft procedure.
As kidney disease stage increased, the use of ACE inhibitors and ARBs fell off dramatically. These agents either were not prescribed or the reason for not prescribing them was not documented. Researchers considered either situation to be nonadherence.
Use of these agents declined from 87% in patients with CKD stage 1 to 58% among stage 4/5 patients. The investigators also observed a steep decline in the use of aldosterone receptor antagonists when their use was appropriate, even in patients with mild CKD.
Patients with more severe renal dysfunction were significantly less likely to receive all interventions except cardiac resynchronization therapy.
The reasons for withholding these therapies are unclear. “Clinicians can be nervous about using these agents in persons with renal dysfunction,” Dr. Heywood said, “although in most cases the drugs are indicated. Sometimes a reduction in the use of these agents is appropriate, but that should be documented in the chart.”