NBER Working Paper No. 23530: The Role of Hospital and Market Characteristics in Invasive Cardiac Service Diffusion

By Jill R. Horwitz, Charleen Hsuan, Austin Nichols
National Bureau of Economic Research, June 2017


Little is known about how the adoption and diffusion of medical innovation is related to and influenced by market characteristics such as competition. The particular complications involved in investigating these relationships in the health care sector may explain the dearth of research. We examine diagnostic angiography, percutaneous coronary interventions (PCI), and coronary artery bypass grafting (CABG), three invasive cardiac services. We document the relationship between the adoption by hospitals of these three invasive cardiac services and the characteristics of hospitals, their markets, and the interactions among them, from 1996-2014. The results show that the probability of hospitals adopting a new cardiac service depends on competition in two distinct ways: 1) hospitals are substantially more likely to adopt an invasive cardiac service if competitor hospitals also adopt new services; 2) hospitals are less likely to adopt a new service if a larger fraction of the nearby population already has geographic access to the service at a nearby hospital. The first effect is stronger, leading to the net effect of hospitals duplicating access rather than expanding access to care. In addition, for-profit hospitals are considerably more likely to adopt these cardiac services than either nonprofit or government-owned hospitals. Nonprofit hospitals in high for-profit markets are also more likely to adopt them relative to other nonprofits. These results suggest that factors other than medical need, such as a medical arms race, partially explain technological adoption.

From the Discussion

Between 1996 and 2014, hospitals have continued to adopt new invasive cardiac services, although the rate of adoption slowed over the study period. Larger hospitals are more likely to adopt new services than are smaller hospitals. For-profit hospitals are more likely to adopt new services than are nonprofit hospitals, which, in turn, are more likely than government hospitals to adopt new services. On average, hospitals appear to make decisions regarding the adoption of new services based on the behavior of competitors in the markets in which they operate, controlling for population size and other characteristics.

The welfare effects of our findings regarding cardiac technology diffusion are uncertain. Although the spread of technology is generally good for social welfare, this has not always been the case with health care technology. Large geographic differences in the provision of care and in spending on care cannot be explained by differences in the population treated and have not led to differences in health outcomes, suggesting that there is a great deal of waste. Cardiac treatments are typically quite profitable services for hospitals, and oversupply is a particular worry for the provision of services that tend to be profitable for providers. In fact, at the extreme, there have been distressing cases of hospitals and physician providing services, particularly profitable services such as cardiac treatments, to patients who did not need the intervention.

Although our study does not measure social welfare directly, the results suggest that current patterns of cardiac technology diffusion can either increase or decrease social welfare, depending on conditions of a health care market. Social welfare is enhanced if hospitals base their decisions to adopt on the existence of unmet medical need in their markets. And, there is some evidence that they are doing so. They are less likely to adopt a new service if the patients in their markets already have geographic access to a service at another hospital.

However, previous research finding little increase in geographic access to care suggests that adoption decisions are in fact driven by a competitor’s decision to adopt. Our results strongly support this finding. Although hospitals respond to the needs of potential patients to be within sixty minutes driving time of an invasive cardiac service, they also respond to the behavior of their competitors and adopt even if doing so duplicates existing services, failing to increase geographic access.


Single payer reform, as envisioned by Physicians for a National Health Program, is much more transformative than merely changing the payment process. One of the more important recommended changes is to convert for-profit entities, such as hospitals, into nonprofit status. Why should that matter?

For-profit business entities must place the interests of their investors first. Nonprofit health care entities place the interests of their patients first. Greedy business decisions are fundamental in the for-profit model which often detracts from optimal patient care, whereas the nonprofit grapples with budget problems in order to make decisions that work best for the patients.

This NBER study is an excellent example of that difference. The authors looked at crucial cardiac interventions – technical innovations that save lives. For-profit hospitals introduced these interventions as part of their competitive involvement in the medical arms race. It did not matter that the community was already being served with these technological advances; they introduced them to increase profits. After all, they are for-profit entities.

In contrast, nonprofit hospitals were less likely to duplicate these technologies if the patient needs were already being served in the community. An exception is that nonprofit hospitals in high for-profit markets were more likely to adopt the for-profit culture and duplicate the services. If the for-profit culture did not exist, it is much more likely that the nonprofits would select technology based on community need rather than profit potentials.

Greed, wasteful duplication of services, and diversion of health care dollars to passive investors are characteristics of the market-driven medical-industrial complex. We do not need nor want that in our health care system. A well designed single payer system includes regional planning and separate budgeting of capital improvements. Efficient and economical uses of resources serve the patients well.

Although we have had a surge of interest in single payer reform, we are now seeing a plethora of opinions, especially from supposedly progressive sources, that the disruption of single payer is not necessary and that we can get to an ideal system merely by simple adjustments such as adding a public option or allowing citizens to purchase Medicare or Medicaid coverage. But this approach would leave in place our fundamentally flawed health care financing infrastructure – by far the most expensive and least efficient model of financing health care. It would accomplish very little of what the PNHP model would.

Individuals touting these incremental steps need to take another look at the PNHP proposal and then explain to us just how their baby steps would ever get us to health care justice for all. Just as the touted gains of the Republican proposals proved to be hallucinatory, these touted gains of the progressives will never fill the vast void that a high performance health care system should be filling.

“Beyond the Affordable Care Act: A Physicians’ Proposal for Single-Payer Health Care Reform”:

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