Researchers analyze relationship between patient volume and performance for 3 cardiovascular conditions

An analysis of outpatient cardiology patients found there was no association between overall practice volume and performance on quality measures for coronary artery disease, atrial fibrillation or heart failure.

However, providers with higher volumes of patients with coronary artery disease and atrial fibrillation had better adherence to those respective performance measures, although providers with higher volumes of patients with heart failure did not have a higher adherence rate.

Lead researcher Lisa M. Fleming, MD, of Tufts Medical Center in Boston, and colleagues published their results online in Circulation: Cardiovascular Quality and Outcomes on Dec. 8.

They analyzed 654,535 adults who enrolled between 2009 and 2012 in the PINNACLE registry, an outpatient-based, prospective quality improvement registry that includes patients from U.S. cardiology practices. The mean age of the patients was 68.5, while 90.7 percent were white and 60 percent had private insurance. They were seen at 71 practices by 1,094 providers, 930 physicians, 102 nurse practitioners and 27 others.

Previous research from the PINNACLE registry found that adherence rates to quality metrics varied from 13 percent screening for diabetes in patients with coronary artery disease to 97 percent blood pressure measurements in heart failure patients.

In this study, the researchers evaluated medication-related performance measures for patients with coronary artery disease, heart failure and atrial fibrillation. The measures for coronary artery disease included beta blocker therapy after MI, antiplatelet therapy, ACE and ARB therapy and lipid-lowering therapy. For heart failure, the measures included beta blocker therapy for patients with an ejection fraction of less than 40 percent and ACE or ARB therapy for patients with an ejection fraction of greater than 40 percent. For atrial fibrillation, the only measure was anticoagulant therapy for patients with a CHADS2 score of 2 or higher.

Of the patients with coronary artery disease, 55 percent were prescribed all of the therapies for which they were eligible. The researchers found that higher monthly provider volumes were associated with improved adherence to performance measures and individual therapies, although there was no significant association between monthly practice volume and adherence to individual medications.

For patients with heart failure, 72 percent were prescribed all of the therapies for which they were eligible. The researchers found that provider and practice volume were not associated with guideline concordance for ACE or ARB therapy. Provider volume was significantly associated with beta blocker therapy, but practice volume was not associated with beta blocker therapy.

Finally, of the patients with atrial fibrillation, 58 percent were prescribed all of the therapies for which they were eligible. The researchers found that providers who saw more heart failure patients were more likely to prescribe anticoagulant therapy, but monthly practice volume was not associated with guideline concordance.

The researchers cited a few limitations of the study, including that the results may not be generalizable to all cardiology practices because practices voluntarily participate in the PINNACLE registry and more than 90 percent of the participants were white. They also mentioned that they obtained data from electronic medical records, so the information may not be complete. The registry also did not distinguish between missing data and no responses.