More than 100 years ago, Boston Surgeon Dr. Ernest Amory Codman took note of data on surgeries at a small semi-private hospital and some other larger and more prestigious hospitals.
“They clearly showed,” he wrote, “that the semi-private hospital not only did more operations, but that the mortality was much lower, especially in some of the more difficult branches of surgery.”
Not quite 50 years ago, results from the National Halothane Study produced some of the first solid statistical evidence of a link between the volume of services and outcomes. Since then, the work of numerous investigators has solidified and expanded the evidence linking volume and outcomes for many treatments, particularly those that are complex and demanding.
A 2000 Institute of Medicine report on this topic noted the history and, looking more recently, found 88 studies that tracked groups of patients treated since 1980. While a complete understanding of the mechanisms and subtleties of the relationship between volume and outcomes has yet to be achieved, the value of considering volume of services as an element of quality improvement has never been clearer. Even so, many patients continue to receive procedures from health care providers who only infrequently do those procedures.
Studying the Volume of Surgeries
With support from the California Health Care Foundation, we recently worked with a group of investigators to study the volume of surgeries for common cancers done in California hospitals (see Note). We identified cancers to study based on a literature review performed by the Cancer Prevention Institute of California, selecting only cases where there was strong evidence of a relationship between volume and patient outcomes. We found 11 cancers that met the criteria: bladder, brain, breast, colon, esophagus, liver, lung, pancreas, prostate, rectum, and stomach.
In each of these areas, based on the literature and working with an expert advisory group, we identified a specific set of surgical procedures used to treat these cancers and worked with the California Office of Statewide Health Planning and Development to calculate the number of surgeries that took place at each hospital in California in 2014.
More than 50,000 residents of California had surgery for one of these cancers, and these patients were treated at a large number of hospitals. Some California hospitals did large volumes of the surgeries we studied. It follows that many people who got a cancer surgery did get it from one of these high-volume places. That’s the good news.
The not-so-good news is that there are quite a few hospitals that did do a given type of cancer surgery in 2014, but only did it rarely. Correspondingly, there are quite a few patients who were the only one, or one of just a few people, to get their surgery at their hospital.
The table below reports some of the key results. Across the 11 procedures, 674 people (not shown) received surgery from a hospital that did only one or two of their procedure in the year, including 51 people with lung cancer, 115 people with stomach cancer, and 24 people with brain cancer.
We did not have enough data to statistically soundly determine whether these patients had worse outcomes than other patients, but the patterns shown in peer-reviewed studies raise the realistic worry that they could well have. Published research shows higher rates of adverse outcomes in hospitals that perform lower volumes of surgeries for certain cancers.
For example, in the case of surgeries for bladder, breast, colon, lung, prostate, and rectum cancers, there is a higher likelihood of postoperative complications; in the case of brain surgery, increased length of stay and increased adverse outcomes after discharge; in the case of stomach cancer, higher rates of transfer and failure to rescue. In the case of all the cancers in this analysis, there is a higher likelihood of mortality in hospitals performing lower volumes of surgery (references to specific studies can be found in the full report [PDF]).
And we might worry that next year something similar will happen. So the real question is how to change this pattern. We have begun to examine this question, and spoken with doctors and administrators at hospitals doing low surgery volumes. The results suggest the complexity of the problem and the importance of taking a multi-pronged approach to solutions.
Methods to Improve
Here are some of the observations and tacks that seem important as we all work to seek improvement.
Providers, health plans and other payers, and government organizations should work to provide more information to patients. It can be very difficult to find out about hospitals’ surgery volumes, even in an age when information transparency has been improving rapidly. We need to release more easily accessible information about volumes.In our data, more than 70% of the patients who got their cancer surgery at a one- or two-procedure hospital could have gone to a hospital among the top 20% of hospitals by volume if they were willing to travel even 50 miles. Standardized measures of volume across all hospitals are valuable, but providing information in the context of the hospital networks of individual health plans is also needed.
Hospitals should work together to improve connections between lower- and higher-volume hospitals. It can be challenging for some patients to get access to high-volume hospitals in a timely way. Some patients may be at risk of ending up as a low-volume surgery recipient because their hospital or physician lacks good connections to a higher-volume facility. There can be times when a nearby higher-volume facility is full, and other options with timely availability are hard to identify. Access may be particularly an issue for lower-income people, including Medi-Cal or uninsured patients.
Health plans and other payers should improve financial incentives for choosing high-volume hospitals. Variation in patient cost sharing could make a powerful difference, in both private and public plans. In addition, improved support for individuals and families that choose to travel to receive care at a high-volume facility would facilitate better choices.
Hospital associations should work with hospital leaders and surgeons to share the substantial evidence base associating low volume with poor outcomes, and encourage hospitals to closely track surgery volume. Providers are not always aware of the links between volume and outcomes. Low volumes often make it harder to pay attention to the risks — one common problem is that providers who do low volumes frequently will not have a bad outcome, despite the heightened statistical risk. A hospital that did a very small number of procedures, but didn’t experience a bad outcome, may easily discount the risk of continuing the pattern.In addition, like patients, doctors and hospital administrators often are not aware of the volumes of services being done at hospitals in their areas, or even at their own institution. Doctors and hospital leaders have a lot to offer to process improvement efforts and need to be on the team figuring out how to address the challenges around low volumes of sensitive procedures.
Physicians themselves, perhaps through specialty societies, should be engaged in identifying targets for hospital volumes that can guide efforts to limit surgeries at low-volume facilities.
Accrediting bodies, such as the Joint Commission, the National Committee for Quality Assurance, and the American College of Surgeons Commission on Cancer should consider incorporating volume of cancer surgeries into their hospital assessments.
Even with these approaches, there will continue to be difficulties. Some patients may not be easily able to travel, even seemingly short distances. Provisions need to be made for starting new surgical programs. Measurement of volume may be best done in the context of the collection of a range of quality data. But much more could and should be done to track, report, and act on hospital volumes for important surgeries.
Note: Our group included Christina Clark and Lisa Moy from the Cancer Prevention Institute of California, Joseph Parker, Merry Holliday-Hanson, and Niya Fong from the California Office of Statewide Health Planning and Development, and Lance Lang from Covered California. In addition, a multidisciplinary Advisory Committee consisting of oncologists, health service researchers, and hospital, payer, and consumer representatives was convened to provide guidance for this project (see page 13 of the full report [PDF]).
Laurence Baker is a health economist and chair of the Department of Health Research and Policy at the Stanford University School of Medicine. A leading health economist, Baker has served as the department’s chief of health services research since 2001. He is also a fellow at Stanford’s Center for Health Policy / Center for Primary Care and Outcomes Research, a senior fellow of the Stanford Institute for Economic Policy Research, and a research associate of the National Bureau of Economic Research in Cambridge, Massachusetts.
Maryann O’Sullivan is an independent health policy consultant whose clients have included the California Health Care Foundation and many other funders in the state. She was the founding executive director of Health Access, a statewide consumer coalition that will soon celebrate its 30th anniversary advocating for health care for all and especially for health care services for low-income populations.