by Erica Cohen

The Joint Commission, the accrediting organization for nearly all hospitals across the United States, recently released its annual list of the top performers on key quality measures.

The list included 620 hospitals, more than 50 percent more than the number named in 2011. The accompanying report summarized the performance of more than 3,300 hospitals on 45 accountability measures such as care for heart attacks, strokes, pediatric conditions, and major psychiatric conditions.

A total of 18 percent of U.S. hospitals achieved the "top performer" designation, and another 17 percent fell just short of the mark. To earn this designation, a hospital needed to score 95 percent or above on a single composite measure that includes all the accountability metrics for which data are reported to The Joint Commission. It also had to meet or exceed a 95 percent performance target for each individual metric.

Accomplishing all of this is no easy feat.

But why were only six Philadelphia-area hospitals – St. Christopher's Hospital for Children, Friends Behavioral Health System, Chestnut Hill Hospital, Paoli Hospital, Delaware County Memorial Hospital, and St. Mary Medical Center – named as top performers?

Philadelphia is home to some of the world's best hospitals according to U.S. News. The Hospital of the University of Pennsylvania (HUP), the Children's Hospital of Philadelphia, and Jefferson University Hospital are consistently ranked among the best in the U.S. How could they have been omitted from the Joint Commission's list?

One possible explanation is that Philadelphia's world-renowned hospitals are much larger and accept sicker patients than the others, which makes it more challenging to meet some of the quality measures assessed by the Joint Commission. For example, HUP has nearly 1.5 million outpatient visits a year, 6,469 employees, and 814 licensed patient beds. Chestnut Hill Hospital, on the other hand, has only 1,170 employees and 135 licensed beds. It is more challenging for a large hospital system with thousands of medical professionals and over a million patients to achieve the 95 percent targets.

In other words, the Joint Commission's list of "top performers" may be skewed in favor of smaller and less technologically equipped hospitals. The measures on which it is based might be more accurate if they were adjusted for the severity of illness in the patients that each hospital treats.

Moreover, the processes of care that the Joint Commission measures do not necessarily translate into better patient outcomes. Therefore, the "top performing hospitals" may not be the ones where patients are treated most effectively.

While the 620 top performing hospitals should be commended for their achievement, patients should realize the limitations of the designation and not discount the excellent quality of care available at other institutions.

Erica Cohen is a third-year law student concentrating in health law at Drexel University Earle Mack School of Law. She graduated from the Scripps School of Journalism at Ohio University with a major in online journalism and minors in business and political science. Prior to attending law school, she worked for DKMS Americas, the world's largest bone marrow donor center. She currently works as a legal intern in the office of general counsel at a local hospital.