Supply-sensitive care refers to services where the supply of a specific resource has a major influence on utilization rates. The frequency of use of supply-sensitive care is not determined by well-articulated medical theory, much less by scientific evidence; rather, it is largely due to differences in local capacity, and a payment system that ensures that existing capacity remains fully deployed. Simply put, in regions where there are more hospital beds per capita, patients will be more likely to be admitted to the hospital. In regions where there are more intensive care unit beds, more patients will be cared for in the ICU. More specialists will result in more visits to specialists. And the more CT scanners are available, the more CT scans patients will receive. The Dartmouth Atlas has consistently demonstrated these relationships.
In regions where there are relatively fewer medical resources, patients get less care; however, there is no evidence that these patients are worse off than their counterparts in high-resourced, high-spending regions. Patients do not experience improved survival or better quality of life if they live in regions with more care. In fact, the care they receive appears to be worse. They report being less satisfied with their care than patients in regions that spend less, and having more trouble getting in to see their physicians. Most studies have found that mortality is no better in higher in high-spending regions, almost certainly because the benefits to some patients are counterbalanced by the harms to others. Hospitals can be dangerous places, where patients face the risk of medical error, adverse events, and hospital-acquired antibiotic-resistant infections. As more physicians get involved in a patient’s care, it becomes less and less clear who is responsible, and miscommunication and mistakes become more likely. Greater use of diagnostic tests increases the risk of finding -- and being treated for -- abnormalities that are unlikely to have caused the patient any problem. Patients who receive care for conditions that would have never caused a problem can only experience the risk of the intervention.
Supply-sensitive care also accounts for more than half of all Medicare spending. Understanding the problem of supply-sensitive care is a critical first step toward improving the quality and affordability of health care, building organized delivery systems, and scaling back costs and cost growth.