(Reuters Health) - Publicly-available ratings of U.S. hospital quality for heart surgery vary so widely from one another they may be more confusing than helpful for patients trying to pick the best place to have a procedure, researchers say.

Out of more than 600 hospitals in a U.S. News & World Report “Best Hospitals for Heart Surgery” list, only two of its top-rated facilities for one common heart procedure were also top-rated for the same surgery by Healthgrades, the Society of Thoracic Surgeons and the Centers for Medicare and Medicaid Services, the study team reports in the Journal of the American College of Surgeons.

“Public ratings of hospitals and surgeons are increasingly being utilized by patients to choose where to seek surgical care,” said senior study author Dr. Ravi Ghanta, chief of cardiac surgery at Ben Taub General Hospital in Houston, Texas.

“Ratings are also utilized by hospital organizations for marketing to patients and the community,” Ghanta told Reuters Health by email. “Inconsistency in these ratings could confuse, rather than clarify, decision making for patients.”

Ghanta and colleagues compared ratings of the 602 hospitals in the 2016-2017 U.S. News & World Report’s list of best hospitals for heart surgery to ratings in three other publicly available and widely used hospital-quality databases: the Society of Thoracic Surgeons’ Adult Cardiac Surgery Database, the Centers for Medicare and Medicaid Services’ Hospital Compare list and Healthgrades, a media company.

The researchers looked at quality ratings for two common procedures, coronary artery bypass and aortic valve replacement. Since all four systems assign hospitals to one of three quality categories, the researchers translated each set of scores to a consistent rating reflecting performance that was better than the national average, average, or worse than average.

They found that the four systems had very different ratings distributions, with ratings for coronary artery bypass matching 50 percent to 85 percent of the time, and for aortic valve replacement, 50 percent to 73 percent of the time.

U.S. News & World Report tended to rate more hospitals as high performing than the other databases, the researchers note. The Society of Thoracic Surgeons and Centers for Medicare and Medicaid Services lists tended to best match each other for coronary artery bypass. For aortic valve replacement, the Society of Thoracic Surgeons and Healthgrades lists tended to match most often.

Only two hospitals were rated as high performers by all four rating systems for coronary artery bypass grafting, and three were rated in this category by all four lists for aortic valve replacement. Overall, hospitals with high ratings were primarily located in California, Florida and New York.

Disagreements between ratings systems were sometimes stark, for example, 13 hospitals were ranked as better than average performers on both procedures by one rating system and worse than average by another. And no hospitals were rated across all four rating systems as poor performers for either procedure.

“This disagreement is due to different data sources and ratings methodologies,” Ghanta said. “Each rating system grades on a different curve.”

Patients are likely unfamiliar with these nuances among the systems, he added. The Society of Thoracic Surgeons system, for instance, is based on a risk-adjusted, audited database that has been developed in recent years to focus on quality improvement. Many heart surgeons view this one as the “gold standard,” he added.

“Rating systems are all over the place, and several studies have shown that hospitals use these ratings as a marketing strategy,” said Dr. Nicholas Osborne, a surgeon and researcher at the University of Michigan in Ann Arbor, who wasn’t involved in the study.

“We’re in real danger when we start replacing measures of quality with rating systems that may not measure or define what quality should be,” he said in a phone interview. “For instance, quality may be different for different procedures.”

Future studies should investigate the best ways to help patients make decisions and learn about the surgical outcomes they want to know, he added.

“The marketing field has long understood how to convey information to consumers, but healthcare has not done well,” Osborne said. “We should know what’s important to patients and how to talk to them about it.”

SOURCE: bit.ly/2yI5Dv1 Journal of the American College of Surgeons, online October 22, 2018.