In the US in recent years, hospital-physician integration has become a dominant form of consolidation in health care. This transition away from independent practice has raised questions about whether hospital-employed physicians may be more likely than independent physicians to refer patients to high-intensity, hospital-based services. We used Medicare claims data from the period 2013-20 to identify patients who received a new diagnosis of stable angina, a common cardiovascular condition that entails clinical discretion in treatment choice. Using linear probability models and an instrumental variables model, we found that patients whose care was managed by a hospital-integrated cardiologist were no more likely to receive stress tests (an office-based procedure) than those whose care was managed by an independent cardiologist. However, these patients were much more likely to receive high-intensity, hospital-based coronary interventions. These results suggest that hospital-physician integration is an important factor in the intensity of treatment received by patients with stable angina. Policy makers may see these findings as additional impetus for more aggressive antitrust enforcement of integrated arrangements between hospitals and physicians and for other regulatory or payment mechanisms that might deter hospitals from using such arrangements to promote high-intensity treatment unnecessarily.