An association between cardiologist billing patterns, healthcare utilization and outcomes in cardiac patients

Background — Whether individual cardiologist billings are associated with differences in ambulatory care management and clinical outcomes in patients with coronary artery disease (CAD) and heart failure (HF) remains poorly understood.

Methods and Results — We conducted a population-based, retrospective cohort study of cardiologists who manage patients with CAD or HF using administrative claims data in Ontario, Canada. The primary exposure was cardiologist billing quintile. We then stratified median billing amounts into quintiles, from lowest (quintile 1) to highest billing physicians (quintile 5). The main outcomes of interest were cardiac diagnostic and therapeutic procedures that occurred within 365 days of the index visit. Our two cohorts respectively consisted of 170,959 patients with CAD seen by one of 423 cardiologists and 56,262 HF patients seen by 413 cardiologists. CAD patients of higher billing cardiologists had higher rates of echocardiograms (adjusted odds ratio (aOR) 1.65; 95% CI, 1.39 to 1.94 for quintile 5 vs. quintile 2) and stress tests (aOR, 1.50; 95% CI, 1.28-1.75) at one year, with a similar pattern for HF patients of echocardiogram (aOR 1.40, 95% CI 1.23-1.59, p<0.001) and stress test (aOR 1.32, 95% CI 1.15-1.51) use. CAD patients of cardiologists in quintile 1 had a higher mortality rate (aOR, 1.16; 95% CI, 1.03-1.31), and HF patients of cardiologists in billing quintile 4 had a lower hospitalization rate at one year (OR 0.94, 95% CI 0.89-0.99, p=0.02).

Conclusions — Cardiac patients seen by the highest billing received more non-invasive cardiac testing compared to lower billing cardiologists.