69% of hospitals exceed average mortality risk for carotid artery stenting

About two in three hospitals certified by Medicare to provide carotid artery stenting (CAS) procedures had higher than average risks for mortality over a two-year period. These findings, published online June 3 in Circulation: Cardiovascular Quality and Outcomes, outline a way to review hospitals to determine which require more scrutiny prior to recertification.

Researchers from the Philadelphia Veterans Affairs Medical Center and the University of Pennsylvania looked at CAS procedures performed at 927 Medicare-certified U.S. hospitals between 2009 and 2011 with the goal of utilizing risk as a means of affirming a hospital’s ability to perform high-quality procedures for its patients. Currently, Medicare requires hospitals prove that they have resources in place to perform CAS procedures and to reaffirm every two years in order to retain certification.

Utilizing risk modeling, Andrew J. Epstein, PhD, et al found that 31 percent of hospitals performed well against the average for risks. Of those, five hospitals stood out with a mean mortality risk of 1.17 percent for the 333 procedures performed between them. All five unnamed top hospitals were nonacademic hospitals from the southern U.S. with black patient populations exceeding 12 percent.

Conversely, among the hospitals with higher mortality risk, two high-volume hospitals were identified as requiring further scrutiny for their outlying risks, but were likewise not named in the published findings.

The researchers found it difficult to accurately represent low-volume hospitals through the risk model. These hospitals appeared to have a high patient mortality frequency relative to patient procedure volume, particularly when a lower “optimal” mean risk was applied. These numbers were relative, as the low-volume group was identified as having fewer than eight CAS procedures over the two-year period.

“Hospitals certified by Medicare for the provision of CAS varied widely in their clinical outcomes, with risk-standardized 30-day mortality rates varying ≈5-fold between the hospitals with the best and worst outcomes,” wrote Epstein et al. They went on to posit that hospitals with significantly higher mortality rates might not measure up to the highest quality of care available.

They stated further, “It would be inadvisable to base certification decisions solely on analyses such as ours; however, our analysis does permit the identification of a small number of hospitals whose clinical performance invites greater scrutiny and for which a comprehensive case review could be conducted by Centers for Medicare and Medicaid Services.”