Various types of providers may perform chronic pain management procedures, and each provider type is subject to certain education, training, certification, and licensure requirements. The range of chronic pain management providers and their practice requirements include the following: Pain physicians. These physicians have completed a subspecialty fellowship training program in pain medicine recognized by ABMS.Following medical school and a residency program in a primary specialty, pain physician candidates must complete an accredited 1-year fellowship and pass an examination to receive board certification. Other physicians. Physicians—including those in specialty and primary care—without certification in pain medicine have comprehensive medical knowledge through their medical school, as well as residency training that can last from at least 3 to 7 years. Although board certification is optional, most physicians take an exam to become certified in a medical specialty. CRNAs. According to the AANA, registered nurses with a Bachelor of Science in Nursing and at least 1 year of experience in an acute setting can pursue certification in nurse anesthesia. Graduates of accredited schools of nurse anesthesia, which provide 24 to 36 months of training, must pass a national examination to receive their certification as CRNAs. Other nonphysician providers, such as NPs or PAs. To become NPs, registered nurses undertake advanced clinical training and complete a master’s program—lasting 1½ to 3 years—or a doctoral program. PAs typically undertake roughly 2 years of master’s-level training. Both NPs and PAs must be nationally certified. Providers must be licensed by the states in which they practice and adhere to state requirements. Physician and PA licensure is administered by state boards of medicine, while nursing licensure is administered by state boards of nursing. Furthermore, all providers are governed by state laws. For example, NPs may or may not be allowed to practice independently or prescribe medications depending on the state in which they practice, and PAs are generally allowed to prescribe medications, but must practice under the supervision of a physician. These laws can take precedence over other location- or payer-specific policies, such as hospital-based privileging. Although CMS has not issued a national coverage determination (NCD) for chronic pain management, some MACs have established local coverage determinations (LCD) for chronic pain procedures. Typically, these LCDs do not address which types of providers may bill Medicare for the services, but rather stipulate certain coverage or billing rules. For example, for procedures that may be given to a beneficiary in a series, an LCD may limit payment to no more than three procedures within a year. LCDs also contain instructions for providers on how to bill Medicare using various CPT codes and modifiers. A given procedure may have several CPT codes that indicate where on the body the procedure takes place or whether additional levels of a procedure were performed. For instance, paravertebral facet joint injections would be billed using one CPT code to indicate a cervical or thoracic location, and another CPT code to indicate a lumbar or sacral location—as well as “add-on” codes to specify when injections occurred on multiple levels of the spine. CMS uses a physician fee schedule to determine the amounts paid to providers for each CPT code billed. Nonphysician providers of chronic pain procedures vary in the percentage of the physician fee schedule they receive. For example, while CRNAs are generally paid 100 percent of the amount a physician is paid for a given procedure under the physician fee schedule, NPs and PAs are generally paid 85 percent of the physician fee schedule. From 2009 through 2012, CRNAs billed Medicare FFS for a small share of our selected chronic pain procedures, while pain physicians and other physicians billed for the largest shares. Of the procedures billed by CRNAs, most were billed by CRNAs in rural areas until 2012. Overall, the various providers’ shares of chronic pain procedures billed to Medicare did not change much over the study period. (See table 2.) The share billed by NPs, PAs, and CRNAs combined grew from 1.4 to 2.6 percent, with CRNA’s billing for less than ½ of 1 percent of all chronic pain procedures in each year. Pain physicians billed for over 40 percent of the selected procedures over the 4-year period, while other physicians billed for over half of the selected services each year. From 2009 through 2012, the trends in shares of Medicare payments by provider type were largely parallel to the trends in their shares of procedures billed. (See table 2.) Combined, CRNAs, NPs and PAs, received less than 3 percent of all payments for these services throughout the period. The pattern of CRNA billing by type of chronic pain procedure shows that CRNAs consistently billed for less than 1 percent of the total. (See table 3.) CRNAs had their largest market share in epidural injections, where they accounted for 0.9 percent of providers’ billings in 2009; this share dropped to 0.6 percent in 2012. CRNAs billed for even smaller shares of facet neurolytic destruction injections, autonomic nerve blocks, and trigger point injections. Over time, the mix of procedures that CRNAs billed to Medicare from 2009 through 2012 changed somewhat. (See fig.1.) Epidural injections represented the largest share—roughly two- thirds—of CRNA-billed procedures, but that share decreased to less than half over the period. The share of paravertebral facet joint injections doubled between 2011 and 2012. Autonomic nerve blocks, facet neurolytic destruction, and trigger point injections billed by CRNAs held relatively small but growing shares of CRNA billing. By state, the trend among CRNAs’ billing for selected chronic pain procedures was largely stable over the 4-year period. (See app. III for state-by-state data.) CRNAs’ share increased by more than 1 percentage point in 2 states, declined by more than 1 percentage point in 6 states, and remained largely unchanged in 42 states and the District of Columbia. States that experienced the most growth in CRNA market share were New Hampshire and Tennessee, increasing 4.4 and 2.5 percentage points, respectively. By 2012, the CRNA share of selected chronic pain procedures was highest in New Hampshire (5.5 percent), Iowa (4.3 percent), and Kansas (4.0 percent). In 43 states and the District of Columbia, the CRNA share remained under 1 percent. Although the number of selected chronic pain procedures billed by all rural providers increased somewhat from 2009 through 2012, the number of procedures billed by CRNAs in rural areas declined over the period. (See fig. 2.) Of all CRNA claims for selected procedures, the share submitted by providers in rural areas fell from 66 percent in 2009 to 39 percent in 2012; meanwhile, the share of selected procedures nationwide billed by all rural provider types was roughly 11 percent in both 2009 and in 2012. In rural markets, provider shares followed the national trends. (See fig. 3.) Of the chronic pain procedures billed by rural providers, CRNA claims were a small percentage. Physicians without board certification in pain medicine billed for the majority of claims from rural providers; however, this number declined over time, while pain physicians billed for an increasing share—almost a third of rural claims in 2012. In mid-2011, Noridian began denying certain chronic pain management services that were billed by CRNAs and maintained this policy through 2012. The denial policy, among other factors, had the potential to affect beneficiary utilization in the Noridian states where CRNAs billed for chronic pain management services. We compared all providers’ billing of selected chronic pain procedures in 2010—the year prior to the denial policy—with that in 2012—the full year in which the denial policy was in place—in the Noridian states with the highest share of CRNAs previously billing for these procedures. In 2009, CRNAs billed for 8 percent of the selected procedures in Montana, 1.7 percent in Wyoming, and 1.4 percent in South Dakota. During that same year, CRNAs accounted for 19 percent of selected chronic pain procedures in rural areas of Montana, 4 percent in rural Wyoming, and less than 1 percent in rural South Dakota. The change in chronic procedures billed between 2010 and 2012 was minimal for the three states overall, but varied by state.providers in those states billed for 28,238 selected chronic pain procedures—of which CRNAs accounted for 2.6 percent—and they billed for 28,155 procedures in 2012 when Noridian denied CRNA claims for these procedures. By state, the number of procedures billed by South Dakota and Wyoming providers declined by 9.2 percent and 6.7 percent, respectively, while Montana provider claims grew by 14 percent over the 2-year period. (See fig. 4.) Nearly all MACs allowed Medicare payment to CRNAs for some, or all, selected chronic pain procedures. As of April 2013, six of the nine MACs had uniform payment policies for CRNA-provided chronic pain procedures across all states within a jurisdiction. The remaining three MACs varied their policies for one state within a jurisdiction. At the state level, MACs reported the following payment policies regarding chronic pain procedures (see fig. 6): allowed payment to CRNAs for all selected procedures in 19 states, allowed payment to CRNAs for a subset of selected procedures in 30 states and the District of Columbia, and denied payment to CRNAs for all selected procedures in the remaining state. In the 30 states and the District of Columbia where MACs allowed payment to CRNAs for only certain chronic pain procedures, MAC payment policies indicated substantial variation in the specific procedures that can and cannot be billed. MACs most commonly denied CRNA payment for trigger point injections and facet neurolytic destruction, allowing CRNA payment for these procedures in only two states. Conversely, MACs allowed CRNAs payment for somatic nerve blocks in 20 states and epidural injections in 16 states. Furthermore, because each procedure can have multiple CPT codes associated with it, MACs may choose to only allow CRNAs payment for some of the CPT codes associated with the procedure and not others. This was the case for epidural injections, transforaminal epidural injections, autonomic nerve blocks, and somatic nerve blocks. Figure 7 illustrates the variation in MAC payment policies for selected CRNA-provided chronic pain procedures in Florida, Nevada, and Pennsylvania. In contrast to their policies on chronic pain procedures, MACs were generally more restrictive regarding payment for CRNA-billed E/M services. As of April 2013, they reported the following payment policies for E/M services (see fig. 8): allowed payment to CRNAs for E/M services in 24 states, and denied payment to CRNAs for E/M services in 26 states and the District of Columbia. Payment policies for CRNA-provided chronic pain procedures did not always align with payment policies for E/M services. In the 19 states where MACs reported that they allowed payment to CRNAs for all chronic pain procedures, they also allowed payment to CRNAs for E/M services. However, among the 30 states for which MACs told us that they allowed payment to CRNAs for only certain procedures, MACs indicated that they allowed payment for E/M services in 5—California, Florida, Hawaii, Kentucky, and Nevada—while denying payment for E/M services in the remaining states and the District of Columbia. The MACs did not implement CMS’s CRNA payment policy consistently; three MACs took steps to apply the policy in 2013, while the remaining six MACs did not. MACs pointed to a number of challenges, including vagueness in state scope of practice laws, that affected their ability to implement the policy. Three MACs took steps to implement CMS’s 2013 rule on CRNA payment and updated their CRNA payment policies, when necessary. CMS officials told us that they rely on MACs to determine whether CRNAs are allowed to provide specific services by reviewing each state’s CRNA scope of practice laws. Two MACs made an effort to determine which services CRNAs are allowed to perform under each state’s scope of practice laws. One of the two MACs directly reviewed the laws of the states in its jurisdiction, while the other MAC contacted each state to ask for its interpretation of the laws. Instead of attempting to interpret state scope of practice laws, a third MAC posted a new educational article on its website notifying CRNAs that they are responsible for knowing which services are allowable under their state laws. The remaining six MACs did not take steps to revisit their CRNA payment policies for 2013. Three of the six MACs reviewed the scope of practice laws for a state in their jurisdictions prior to CMS’s 2013 ruling at the request of the state or provider groups. For instance, one MAC stated that when it began its contract in 2009, the CRNA association for one of its states asked the MAC to consider allowing its CRNAs to be paid for chronic pain services, citing a long-standing history of providing these services. At that time, the MAC reviewed the state’s CRNA scope of practice laws and determined that they did not preclude CRNAs from providing chronic pain services. It then extended this affirmative payment policy across all states within its jurisdiction without reviewing further state laws. When asked about its implementation of CMS’s 2013 CRNA payment policy, this MAC told us that it had not revisited any state scope of practice laws. Two of the six MACs reported that they have overarching policies in place to determine coverage for all nonphysician provider types and, therefore, have not taken any steps to implement this latest CRNA payment policy. For example, one of these MACs noted that nonphysician providers must submit a request to the MAC to receive payment for a specific CPT code. The MAC will then review the relevant state scope of practice law and determine whether to allow payment for that code. The remaining MAC reported that it was waiting for further instructions from CMS before implementing the policy. MACs discussed a variety of challenges that affected their implementation of CMS’s CRNA payment policy. Most MACs reported challenges interpreting state scope of practice laws to make determinations about which services CRNAs are allowed to provide, noting that state scope of practice laws are generally vague and lack details about which specific services CRNAs can perform. MACs that asked states to provide an interpretation of the scope of practice laws reported that the states generally were unable to provide definitive responses. For instance, one MAC that looked into a state’s CRNA scope of practice in 2010 told us that the process to determine whether the state law allowed CRNAs to perform chronic pain services was convoluted; the MAC was directed back and forth between many state and federal officials and provider groups. Another MAC said that when a determination could not be made about a state’s scope of practice, it defaulted to allowing payment for all services approved by the AANA. A few MACs discussed the difficulty of differentiating between acute and chronic pain services for payment purposes. Because CPT codes for services used to treat chronic pain are also used to bill for acute pain care in the peri-operative setting, one MAC told us that the only definitive way to determine whether the service was for chronic or acute pain is to review the medical record. However, some MACs explained that since chronic pain procedures are typically provided in an outpatient setting, they can rely on the place of service listed on the claim to make a best guess at whether the procedure was used to treat chronic pain. In addition, a few MACs noted that the frequency of the service can also be an indicator, with multiple injections billed for a patient by the same provider over a period of time indicating that the procedure was likely used to treat chronic pain. Two MACs assumed that Medicare’s rule requiring physician supervision of anesthesia services provided by CRNAs in hospital and ASC settings applied to chronic pain services in all settings; this assumption has potential implications for CRNA billing of chronic pain services. Under this rule, CRNA-provided anesthesia services furnished in hospital and ASC settings must be performed under the direction of a physician unless a state’s governor has opted out of this requirement. CMS guidance clarifies that this requirement applies to anesthesia services and not to analgesia services, which are defined to include services used to dull or alleviate pain without other effects, such as the loss of consciousness; the guidance does not expressly use the term “chronic pain management.” These two MACs took the view that they would have needed to review CRNA scope of practice laws only in states that had opted-out of the supervision requirement, implying that they considered chronic pain management services to be anesthesia services. Regardless of the validity of this interpretation, the supervision rule only applies in hospital and ASC settings, not office settings. By applying this rule to office settings, these MACs may have unnecessarily restricted the services for which CRNAs in 10 of the states under these MACs’ jurisdictions are allowed to bill. Use of state scope of practice laws to govern Medicare coverage of CRNA-provided chronic pain care continues to be an area of uncertainty and confusion for many MACs. Similarly, certain MACs have interpreted the CRNA supervision rule, as it relates to CRNA-provided chronic pain management services, in a way that may inappropriately limit CRNA billing for such services when furnished in office settings. As a result, MACs have not implemented CMS’s 2013 payment rule in a consistent manner that ensures appropriate beneficiary coverage and provider payment. Although CRNAs do not bill for a significant share of the chronic pain procedures we reviewed, if a MAC improperly denies payment to CRNAs in a state that allows CRNAs to independently furnish such services, beneficiary access to these services may be unnecessarily affected. In order to ensure consistent implementation of CRNA payment policy, we recommend that the Administrator of CMS (1) provide specific instructions to MACs on how to determine coverage with reference to a state’s scope of practice laws, including instructions on how to proceed if the state scope of practice laws are not explicit, and (2) clarify the applicability of the CRNA supervision rule to payment for CRNA-provided chronic pain management services. We provided a draft of this report to HHS for comment. In its written response, reproduced in appendix IV, HHS concurred with our two recommendations. Regarding our recommendation to provide specific instructions to MACs on how to determine coverage with reference to a state’s scope of practice laws, HHS stated that CMS plans to send a letter directing all MACs to seek clarification from appropriate state officials or entities if state scope of practice laws are not explicit. Regarding our recommendation to clarify the applicability of the CRNA supervision rule to payment for CRNA-provided chronic pain management services, HHS stated that CMS will clarify that the supervision rule governs only anesthesia services furnished in hospitals or ASCs. HHS also provided technical comments that we incorporated as appropriate. As agreed with your offices, unless you publicly announce the contents of this report earlier, we plan no further distribution of it until 30 days from its date. At that time, we will send copies to the Secretary of Health and Human Services. In addition, the report will be available at no charge on the GAO website at http://www.gao.gov. If you or your staffs have any questions about this report, please contact me at (202) 512-7114 or cosgrovej@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix V. This appendix describes our methodology for analyzing recent trends in billing for selected chronic pain procedures, as well as changes in the number of procedures billed during the period of Noridian Healthcare Solutions (Noridian) denials. It also describes our efforts to ensure the reliability of the data. We focused our review on a set of seven categories of chronic pain procedures and corresponding current procedural terminology (CPT) codes. To select procedures, we obtained an American Association of Nurse Anesthetists (AANA) list of CPT codes that are billed by certified registered nurse anesthetists (CRNA). We categorized the CPT codes by procedure, in consultation with nurse and physician pain experts. We narrowed this list to procedures that were either reported by a Medicare Administrative Contractor (MAC) billing specialist as most likely to be used in treating chronic pain (as opposed to acute pain), or those commonly mentioned across payer resources—such as local coverage determinations (LCD)—as pain management options. We excluded other types of chronic pain management services, such as evaluation and management (E/M) and pharmacological services because of the unavailability of reliable data. The procedures we selected to include were: autonomic nerve blocks, paravertebral facet joint injections, trigger point injections. This category excludes codes used for emerging technologies, services, or procedures. To determine trends in billing for the selected procedures, we analyzed 100 percent of Medicare fee-for-service (FFS) paid claims from 2009 through 2012. We calculated the number of procedures billed to Medicare FFS from the carrier/physician file, excluding claims billed by some critical access hospitals. We considered procedures administered on more than one vertebral level of the spine to be separate procedures. We derived overall expenditures for selected chronic pain procedures from both provider payments (through the physician/carrier file) and outpatient facility payments (through the outpatient file). We took additional steps in an effort to narrow our focus to procedures used to treat chronic pain. First, we excluded claims for procedures billed as distinct procedural services during the same encounter as another procedural service, where normally both would not be billable. We confirmed with several Medicare or chronic pain billing experts that, while not exclusively, these procedures are more likely than not to be for acute pain occurring in conjunction with another procedure. Additionally, we excluded claims in the carrier/physician file for procedures performed in the hospital inpatient setting. Several MACs told us that chronic pain is treated almost exclusively in outpatient settings. While these steps mitigated overcounting the number of chronic pain procedures, our analysis may still include some acute procedures and may exclude some chronic procedures. We disaggregated biller (provider) type based largely on the provider specialty indicated on the claim.physician biller type. To identify physicians that are board certified in pain medicine—pain physicians—we cross-referenced the names of physicians provided by the American Board of Medical Specialties (ABMS) as board certified in pain medicine, to a list of all Medicare providers, as maintained by the Centers for Medicare & Medicaid Services (CMS) through the National Plan and Provider Enumeration The exception to this is the pain System (NPPES).match 91 percent of the pain physicians to NPPES records. We then used the provider identifier from the NPPES data to identify pain physicians on the claims. Using a name-matching strategy, we were able to Our count of procedures provided by nonphysicians may be conservative. For example, physicians and certain other providers may bill “incident to”—whereby, for example, a physician might bill for a supervised service or procedure furnished by a nurse practitioner (NP), physician assistant (PA), or CRNA. There is no way on the claim to determine when a service is billed “incident to,” rather than provided completely by the billing professional. Services billed “incident to” indicate the specialty of the billing professional. To the extent that nonphysician professionals provided services in whole or in part that were billed “incident to” another professional, we may have undercounted procedures provided by CRNAs, NPs, or PAs. In addition, providers, including pain physicians, can reassign their billing so that their employer may bill on their behalf. In this case, the provider identifier on the claim would be that of the employer, and we would not capture the provider as a pain physician based on our name matching strategy. We also disaggregated the data by geographic location. To analyze urban and rural biller (provider) status, we used the CMS Core-Based Statistical Area crosswalk to identify those rural providers as providers with a zip code that is not associated with a Core-Based Statistical Area. To determine the extent to which the number of selected chronic pain procedures billed to Medicare FFS changed during the period of denials, we analyzed Medicare FFS claims from 2009 through 2012 in those states under Noridian’s jurisdiction that were subject to CRNA denials and under Noridian’s jurisdiction for all 4 years of the study period. At the time of our analysis, Noridian’s jurisdiction included Alaska, Arizona, Idaho, Montana, North Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming. We excluded Washington state, where CRNAs are dually trained as NPs, and thus not subject to the denials. We also excluded Idaho because it was under another contract until 2011. We then limited our analysis to those states where CRNAs constituted at least 1 percent of the chronic pain provider market in 2009: Montana, South Dakota, and Wyoming. We measured the overall number of procedures billed to Noridian for the same set of selected chronic pain procedures, using the same methodology as in the broader trend analysis. We compared billing for selected chronic pain procedures prior to the MAC denials—which began in 2011—to billing in 2012 when the MAC denial policy was fully implemented. We assessed the trend both state-wide and in rural areas. We ensured the reliability of the Medicare claims data, ABMS pain physician data, and NPPES data used in this report by performing appropriate electronic data checks, reviewing relevant documentation, and interviewing officials and representatives knowledgeable about the data. We found the data were sufficiently reliable for the purpose of our analyses. We conducted this performance audit from March 2013 through February 2014 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. From 2009 through 2012, the number of selected chronic pain procedures billed to Medicare fee-for-service (FFS) grew by about 5.7 percent annually, while Medicare spending on these procedures grew at a slightly higher rate. (See tables 4 and 5.) Growth rates varied across procedures; for example, claims for somatic nerve blocks and paravertebral facet joint injections rose more rapidly at about 11 percent and 9 percent per year, respectively, while claims for epidural injections rose by about 2 percent annually. Overall, Medicare payments for selected chronic pain procedures increased somewhat faster than the number billed, rising 6.5 percent annually between 2009 and 2012. (See table 5.) This rate of growth is above the average growth rate of 5.3 percent per year in overall Medicare Part B spending over the same period. As with the trend in the number billed, average annual growth in expenditures varied across selected chronic pain procedures; expenditures grew most rapidly for somatic nerve blocks (20 percent annually) and facet neurolytic destruction (13 percent annually), while expenditures for epidural injections grew least rapidly (5 percent annually). This appendix provides further detail on how certified registered nurse anesthetists’ (CRNA) market share of selected chronic pain procedures changed between 2009 and 2012, by state. In addition to the contact named above, Rosamond Katz, Assistant Director; Sandra C. George; Richard Lipinski; Kate Nast; and Kathryn Richter made key contributions to this report.

Summary: Chronic pain costs the nation about $600 billion each year, a quarter of which is borne by Medicare. One MAC, Noridian Healthcare Solutions (Noridian), began denying CRNA claims for certain chronic pain services in 2011, citing patient safety concerns. CMS issued a rule, effective January 2013, clarifying that CRNAs can bill Medicare for “any services that a [CRNA] is legally authorized to perform in the state in which the services are furnished,” including chronic pain management services. GAO was asked to review Medicare's payment policy regarding the provision of chronic pain management services by CRNAs. This report examines, among other things, (1) trends in Medicare provider billing for selected chronic pain procedures; (2) in which states MACs allowed payment for selected procedures billed by CRNAs as of early 2013; and (3) how MACs implemented the payment policy. To do this, GAO selected seven categories of chronic pain procedures, in consultation with pain care experts. GAO analyzed Medicare claims data from 2009 through 2012, by provider type and geography. To determine which MACs allow CRNA payments and how MACs implemented CMS's policy, GAO interviewed medical directors at all nine MACs. From 2009 through 2012, certified registered nurse anesthetists (CRNA)—a type of advanced-practice nurse specializing in anesthesia care—billed Medicare fee-for-service (FFS) for a minimal share of selected chronic pain procedures, less than ½ of 1 percent of these procedures in each year. Physicians without board certification in pain medicine billed for the majority of selected procedures each year, while pain physicians consistently billed for roughly 40 percent of selected procedures. Furthermore, although the number of chronic pain procedures billed by all rural providers increased from 2009 through 2012, the number of procedures billed by rural CRNAs declined over the period. Of all CRNA claims for selected procedures, the share billed by CRNAs in rural areas fell from 66 percent in 2009 to 39 percent in 2012. As of early 2013, Medicare Administrative Contractors (MAC)—entities that pay medical claims on behalf of Medicare—allowed payment to CRNAs for all selected procedures in 19 states, allowed payment for a subset of selected procedures in 30 states and the District of Columbia, and denied payments for all selected procedures in 1 state. Where MACs allowed payment to CRNAs for only certain procedures, payment policies indicated substantial variation in the specific allowed procedures. Three of the nine MACs took steps to implement a Department of Health and Human Services' (HHS) Centers for Medicare & Medicaid Services (CMS) rule, effective January 2013, that defers to state scope of practice laws to inform coverage for CRNAs. CMS relies on MACs to review each state's CRNA scope of practice laws. However, most MACs reported difficulty interpreting state scope of practice laws regarding the services that CRNAs are allowed to provide; MACs noted that state scope of practice laws generally lack detail on which specific services CRNAs can perform. In addition, two MACs assumed that Medicare's rule requiring physician supervision for anesthesia services provided by CRNAs in hospital and ambulatory surgical center settings applied to chronic pain management services provided in all settings; this may have unnecessarily restricted the services for which CRNAs are allowed to bill in certain states. GAO recommends that CMS provide specific instructions to MACs on (1) how to determine coverage with reference to a state's scope of practice laws, and (2) the application of the CRNA supervision rule. HHS concurred with these recommendations.