by Based on Cheryl Clark, HealthLeaders article 5/2015
Published on Feb 27, 2017

After a decade in which physicians and observers focused on process and outcome measures, the pendulum is swinging back toward viewing volume as the best barometer of hospital quality. Or maybe volume is being recognized for the important role it plays in quality.

Back in 2001, the Leapfrog Group, an advocacy group of Fortune 500 corporations which purchase health insurance for their employers, in an effort to help employers and patients make better choices about hospital care, became the first advocacy group to include procedural volume as a proxy for quality of care.

Leapfrog scored reporting hospitals on how often they performed six procedures, setting minimum numbers for each necessary for proficiency: Coronary artery bypass grafts, coronary angioplasty, carotid endarterectomy, esophageal cancer surgery, abdominal aortic aneurysm repair, and high-risk obstetrics. Later came aortic valve repairs and pancreatectomies.

Leapfrog's move garnered criticism at the time, but was based on numerous studies published in medical journals showing that procedure volume was a reliable quality measure at the time.  But over the past decade, quality measurement efforts moved away from volume. Volume was obviously just a proxy. What we cared about was good outcomes, and if we could measure outcomes directly, why bother with volume? Although high-volume centers may be, on average, better than low-volume centers, surely there are some poor-performing, high-volume centers and well-performing, low-volume ones. So the thinking was that we could dispense with volumes if we could directly measure outcomes such as mortality and complications. 

Over the years, new metrics have been added to the equation of what determines quality and today, those many of those measures are assoicated with adjustments to hospital payments that can represent nearly 6% of a hospital's annual Medicare payments.  But many are under fire as hospital execs point out bias or flaws such as the 30 day readmission rate becuse it lacks an adjustment for socioeconomic status and unfairly punishes hospitals that treat the poor. 

So, the experts are back to volume.  The notion is simple and intuitive: practice makes perfect; experience creates better physicians. Surely, a surgeon who performs a single esophagectomy a year will do the surgery less well and manage complications less effectively than a surgeon who does one every week or even every month. This is why surgical training is so long and why we value experts who have seen many cases similar to the one confronting them today.

The current return to volume as a proxy for quality also comes with a far more sophisticated understanding of why volume matters, and it’s not just that practice makes perfect. High-volume centers likely have teams that work more effectively together, systems to identify complications early, and the ability to effectively respond to complications. They also may be more likely to have critical support programs, such as wound care, nutrition, and occupational therapy, to maximize patients’ abilities to return to their activities of daily living.

Yes, there are other research findings that may challenge the notion of volume as a quality metric, all of which suggest that the story is a bit more complicated than “practice makes perfect.”