The study did not address why opting-out might increase costs. The researchers said several factors may contribute to this unexpected finding, including that nurse anesthetists may take longer to perform the same services, and working without physician supervision may lead to worse surgery outcomes, which requires additional treatment.
"The findings of this study underscore the point that before we make a policy or pass a new rule, we first need to rigorously study what the potential effects might be," said study lead author John Schneider, Ph.D., CEO of Avalon Health Economics. "A lot of states thought that by opting-out of the federal requirement, they would be increasing access to care. It turns out that simply opting-out is not a guarantee of increased access."
Since 2001, 17 state governors have exercised the option to opt-out of a federal rule that physicians supervise the administration of anesthesia by nurse anesthetists, most citing increased patient access to anesthesia care as the rationale for the decision.
The "opt out" provision was created due to a concern about a potential shortage of physician anesthesiologists, at least in some regions and states. The presumption was that allowing nurse anesthetists to practice without physician supervision would alleviate potential shortages, and enhance access to anesthesia care. Additionally, a lower professional service cost for nurse anesthetists practicing without physician supervision was presumed to lower anesthesia care costs.
This is the fourth study in just over a year that looked into whether the adoption of the opt-out rule impacted access to anesthesia care. All four studies found that opt-out does not increase access to anesthesia care. One study found that across urgent diagnoses, opt-out was not associated with increased access to anesthesia services. Another study found opt-out was associated with little or no increased access to anesthesia care for common procedures.
"The new study extends the literature on the impact of state opt-out policy by adding an assessment of its impact on costs of surgeries, and by assessing its impact on a wider variety of procedures requiring anesthesia services than in prior studies," the researchers wrote.
To analyze the effect of the opt-out rule on inpatient surgery, researchers used the largest publicly available all-payer (including all types of public and private insurance) health care database in the United States, which included many opt-out and non-opt-out states. For outpatient surgery, they used a database of outpatient surgery and services provided by hospital-owned and nonhospital-owned surgery facilities.
The outpatient analysis included three opt-out states (California, Colorado and Kentucky) and three non-opt-out states (Florida, Maryland and New Jersey). The analysis used data from multiple years of U.S. inpatient hospital discharges and outpatient surgeries. The outpatient database did not provide cost estimates for outpatient procedures, so the researchers were unable to evaluate the opt-out rule's effect on outpatient surgery costs.
"Unlike previous opt-out studies, the design of this study allowed us to better isolate the effect of the opt-out policy across states and over time," said Dr. Schneider.
"The primary intent of the opt-out rule was to improve access to anesthesia services by reducing barriers to utilize nurse anesthetists and increasing their scope of practice. In turn, the hypothesis is that the reduction in barriers will increase access to surgical care. In our study, we did not find evidence to support this belief," the researchers concluded.
