Results of an observational study show that contrary to what might be expected hospitals accredited by independent organizations, such as the Joint Commission, are associated with no better patient outcomes than hospitals reviewed by a state survey agency.

"Private hospital accreditation including by the Joint Commission – 30-day readmissions, or improved patient experience compared with hospitals undergoing a state survey," said first author Miranda B. Lam, MD, MBA, Brigham and Women's Hospital and the Harvard TH Chan School of Public Health, Boston, in an email exchange with the | Medscape Cardiology .

The Joint Commission has recently been under attack for questionable standards and offering an expensive hospital-accreditation process that yields few benefits to hospital or patients.

In early October, the  Wall Street Journal reported stepped-up federal oversight of hospital-accreditation organizations. Este followed an earlier Journal report, which indicated that problem-plagued hospitals did not have their accreditation even when they were found to have serious safety violations.

Hospital accreditation by either a private organization, like the Joint Commission or by a state survey agency is required by the Centers for Medicare and Medicaid Services as part of their Conditions of Participation. With about 80% of the nation's hospitals opting for Joint Commission accreditation, the organization has turned into an important safety watchdog.

The main results showed:

1. Thirty-day risk-adjusted mortality at the accredited hospitals was slightly but not statistically significantly lower than that seen by hospitals reviewed by a state survey agency (10.2% vs 10.6%; difference, 0.4%; (95% confidence interval [CI], 0.1 % – 0.8%,  = .03).

2. Mortality rates for the six surgical conditions were nearly identical (2.4% vs 2.4%, difference 0.0%, 95% CI, -0.3% to 0.3%,  = .99).

3. Thirty-day readmissions for the 15 medical conditions were significantly lower, albeit only one percentage point difference, favored accredited hospitals (22.4% vs.23.2%,  P  <.001), a difference the researchers called "modest," but no difference was seen for the surgical procedures (15.9% vs15.6%; P  = .75).

4. Patient experience scores were "modestly" but not reported at hospitals accredited by state survey agencies (summary star rating, 3.4 vs3.2; P  = .06). Similarly, no difference in patient satisfaction was seen between the Joint Commission hospitals and those accredited by other independent organizations.

The researchers used risk adjustment to counter the risk for potential confounders and baseline differences between institutions.