Anesthesiologist involvement in screening colonoscopies among Medicare beneficiaries increased substantially from 2001 to 2006. This trend was compounded by the doubling of the screening colonoscopy rate. As a result, there has been a profound increase in the number of screening colonoscopies with anesthesiologist involvement at the population level. This represents a significant change in practice. At the same time, it has yet to be determined whether patient outcomes are actually improved by anesthesiologist involvement.
The involvement of anesthesiologists in screening colonoscopies has attracted substantial interest amongst gastroenterologists, anesthesiologists, and payers given the financial implications associated with anesthesiologist involvement. A more recent Medicare estimate from 2009 is that the national mean allowed charge for code 00810 is $120 per case (CMS), which raises the financial impact compared to the estimate of $103 per case used in our study.
This shift in care patterns raises the question of the degree to which screening colonoscopy’s cost is affected by anesthesiologist involvement. A cost-effectiveness analysis for CRC screening that was performed for the United States Preventive Services Task Force (USPSTF) estimated the cost of a colonoscopy without polypectomy to range from $285 to $69513
with an average of $490, which is very close to the approximately $498 value that we used based on the 2007 AHRQ analysis. This analysis also showed that incremental cost effectiveness ratios for screening colonoscopy every 10 years ranged from $10,997 to $12,271 per life-year saved.13
With our estimate of a rise in cost of approximately 20% with anesthesiologist involvement, a thorough assessment of the cost effectiveness of screening colonoscopy with the added cost of anesthesiologist involvement warrants further attention.
There was no significant difference found in anesthesiologist involvement across age groups in our study period. It is often speculated that older persons receive higher levels of anesthesiologist involvement. However, it is possible that this reflects a difference between patients under versus over 65 years and does not apply to increasing ages among patients over 65 years of age.
Variation exists across regions in terms of the percentage of screening colonoscopies that involve an anesthesiologist or CRNA. In fact, a patient undergoing a screening colonoscopy in San Francisco or New Jersey had 0.18 and 15.43 fold odds, respectively, of having anesthesiologist involvement compared to a patient in Iowa. One explanation for the variation in the amount of reimbursement to anesthesiologists across regions may be due to local payor policy.14
Patient income and cost associated with anesthesiologist involvement also carry financial implications and have an effect on practice patterns.
Our study does have limitations. SEER provides data for 17 registries; however, this remains a representative sample of approximately 28% of the United States population and does not include all areas that Medicare covers.10
It does not take into account the competition among gastroenterology practices in specific regions, specific volume of cases per session per practitioner, an in-depth look at cases being performed side by side with patients of other third-party payors, or non-screening colonoscopy cases. The claims data has limitations in its ability to determine settings in which a nurse anesthetist practices independently for anesthesia services without the presence of an anesthesiologist. Also, this study focuses on utilization data and does not take into account any data on the patient perspective on the sedation being administered by an anesthesiologist in comparison to endoscopist-directed administration. Prior studies have demonstrated that a significant barrier to CRC screening for patients is the fear of pain or complications associated with the procedure.15–16
It is unclear whether anesthesiologist involvement is associated with increased safety. One study reported a peri-procedural mortality rate of approximately 1 in 14,000,17
and it is unknown whether anesthesiologist involvement further decreases the mortality rate.
As a result of the high cost estimates associated with anesthesiologist involvement, there has been evaluation of endoscopist-directed administration of propofol, which has been shown to be safe.18
A recent position statement by the American Society for Gastrointestinal Endoscopy (ASGE) states that the use of anesthesiologist-administered propofol for healthy individuals undergoing elective endoscopy is very costly without demonstrated improvement in patient safety or procedural outcome.19
On the other hand, anesthetists continue to urge for the administration of propofol only by persons trained in the administration of general anesthesia who are not simultaneously involved in the surgical or diagnostic procedure.20
We found that nearly a quarter of screening colonoscopies being performed in the Medicare population have anesthesiologist involvement and that the involvement varies dramatically across regions. Future research is needed to assess the impact on patients and outcomes associated with anesthesiologist involvement. The patient perspective regarding comfort and willingness to undergo the procedure with anesthesiologist involvement warrants further evaluation. An investigation of the potential benefits, including polyp detection rate, and potential risks, including the complication rate, with and without anesthesiologist involvement may help to determine the most safe and cost-effective approach to screening colonoscopies.