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Background In 1992, Medicare implemented the resource-based relative-value scale, which established payments for physicians' services based on relative costs. We conducted a study to determine how the use of physicians' services changed during the first decade after the implementation of this scale.
Methods With the resource-based relative-value scale, Medicare payments are based on the number of relative-value units (RVUs) assigned to physicians' services. The total number of RVUs reflects the volume of physicians' work (the time, skill, and training required for a physician to provide the service), practice expenses, and professional-liability insurance. Using national data from Medicare on physicians' services and American Medical Association files on RVUs, we analyzed the growth in RVUs per Medicare beneficiary from 1992 to 2002 according to the type of service and specialty. We also examined this growth with respect to the quantity and mix of services, revisions in the valuation of RVUs, and new service codes.
Results Between 1992 and 2002, the volume of physicians' work per Medicare beneficiary grew by 50%, and the total RVUs per Medicare beneficiary grew by 45%. The quantity and mix of services were the largest sources of growth, increasing by 19% for RVUs for physicians' work and by 22% for total RVUs. Our findings varied among services and specialties. Revised valuation of RVUs was a key source of the growth in RVUs for physicians' work and total RVUs for evaluation and management and for tests. New service codes were the largest drivers of growth for major procedures (accounting for 36% of the growth in RVUs for physicians' work and 35% of the growth in total RVUs), and the quantity and mix of existing services were the largest drivers of growth for imaging. The growth in RVUs for physicians' work was greatest in cardiology (114%) and gastroenterology (72%). The total growth in RVUs was greatest in cardiology (99%) and dermatology (105%).
Conclusions In the first 10 years after the implementation of the resource-based relative-value scale, RVUs per Medicare beneficiary grew substantially. The leading sources of growth varied among service types and specialties. An understanding of these sources of growth can inform policies to control Medicare spending.
Early policy simulations suggested that when the resource-based relative-value scale was phased in (by 1995), it would increase payments for evaluation and management services by 25 to 30%, decrease payments for procedures by 25%,4 and redistribute overall payments toward evaluation and management services5 and the physicians' specialties that furnish mainly those services.6 Medicare's relative values for practice expenses and professional-liability insurance were based on historical charges until 1999 and 2000, respectively, when resource-based values for these components were phased in. By 2002, the entire system's relative values were derived from estimates of resource costs. Like the original resource-based relative-value scale, the shift to resource-based values for practice expenses and professional-liability insurance was intended to better align payments with resource costs, and this shift was expected to redistribute payments toward evaluation-oriented services.
The resource-based relative-value scale was never expected to control overall Medicare spending on physicians. To do that, Congress established performance standards based on the volume of physicians' services and, in 1997, a sustainable growth rate for use in determining the annual update to the conversion factor.6,7 Recently, Congress has overridden these policies and determined the updates without strictly adhering to the sustainable growth rate, because this rate would have resulted in annual reductions in Medicare fees.
The Centers for Medicare and Medicaid Services (CMS) maintains the resource-based relative-value scale, relying on recommendations from the Specialty Society Relative Value Update Committee of the American Medical Association (AMA). During the first 10 years after its introduction, the scale was altered annually to introduce new service codes and make revisions to codes for which definitions had been modified. In addition, two comprehensive reviews (known as 5-year reviews) of relative values for physicians' work were performed in 1997 and 2002, as required by statute.8,9 Policymakers and stakeholders focus on these refinements to the scale and on the annual update, since they are the main policy levers that influence Medicare spending on physicians' services. However, other factors play important roles in determining the growth and distribution of Medicare's spending on physicians. Most directly, growth in the number of beneficiaries adds to spending, even if the fee schedule remains static. Spending also increases as a result of the introduction and application of new service codes and the expanded application of existing services.
The literature on Medicare's resource-based relative-value scale includes assessments of the early effects of the system on all specialties4,6 and numerous articles on its effects on particular specialties.10,11 However, we are not aware of recent or cumulative assessments of the effect of the scale on all service types or major specialties or of examinations of the sources of changes to the scale. We analyzed the overall growth in the volume of physicians' services per Medicare beneficiary during the first 10 years after the introduction of the Medicare fee schedule. We also examined the contributions to that growth that were made by refinements of existing service codes in the scale, the addition of new codes, and the growth in the quantity and mix of existing services.
Methods
Data
We used annual claims files from the CMS for data on the use of Medicare physicians' services in 1992 and 2002. We obtained files on RVUs for 1992 through 2002 from the AMA.12 Files on RVUs list the values for physicians' work, practice expenses, and professional-liability insurance for each service paid for through the Medicare fee schedule. Using these files and claims files from 1992 and 2002, we calculated the RVUs for physicians' work and total RVUs for services paid for through the Medicare fee schedule in those years. We also obtained a file from the AMA that identified the review status of all services ever paid for through the Medicare fee schedule. Categories for the review status included new codes, codes reviewed during the first or second 5-year review, codes reviewed during the annual review process, and codes not yet reviewed.
Calculations of Service Volume
An RVU is the unit of measure for the resource-based relative-value scale; each service is assigned a specific number of RVUs according to its relative resource costs. Since payment rates are determined by multiplying RVUs by a single conversion factor, RVUs are analogous to relative payment rates. In this study, we used RVUs to calculate an intensity-weighted measure of the quantity of service — this measure is called "RVU volume."13 Thus, RVU volume in a given year is the sum, for all services, of the number of units of each service multiplied by the RVU value assigned to that service in that year. We calculated the RVU volume for physicians' work and total RVUs (which includes RVUs for physicians' work, practice expenses, and professional-liability insurance). We accounted for the increase in Medicare beneficiaries over the 10-year period by dividing the RVU volume for physicians' work and total RVU volume in 2002 by the number of beneficiaries in 2002 and the RVU volume amounts in 1992 by the number of beneficiaries in 1992.14
We calculated the aggregate percent change in the RVU volume for physicians' work and the total RVU volume per beneficiary over the 10-year period, for all services and according to service type and specialty, as follows: [(the RVU volume in 2002÷the RVU volume in 1992)–1]x100. We also examined changes in the percent distribution of the RVU volume for physicians' work and total RVU volume per beneficiary among service types and specialties.
We then calculated three components of the aggregate change in the RVU volume of physicians' work and the total RVU volume per beneficiary: changes in the quantity and mix of services from 1992 through 2002, revisions of the valuation of RVUs for existing services, and the introduction of new service codes after 1992. We used the following calculation for changes in the quantity and mix of services: [(the quantity of existing services in 2002x1992 RVU values for each service)÷(the quantity of services in 1992x1992 RVU values)–1]x100. Policymakers and researchers use such a calculation of the quantity and mix of services when analyzing changes in the volume of physicians' services.15,16,17,18,19
We calculated revisions of the valuation of RVUs as follows: [(the quantity of existing services in 2002x2002 RVU values for each service)÷(the quantity of existing services in 2002x1992 RVU values)–1]x100. This calculation reflects the effect of "price" changes for existing services due to RVU revisions made by the CMS and the Relative Value Update Committee of the AMA.
We used the following calculation for the introduction of new service codes: [(the quantity of all existing and new services in 2002xthe 2002 RVU values for each service)÷(the quantity of existing services in 2002x2002 RVU values)–1]x100. This calculation reflects the effect of new service codes.
These three component rates of growth, when multiplied together, are equal to the aggregate growth rate calculated above. To present our results in a clinically meaningful way, we analyzed physicians' services, using the Berenson–Eggers Type of Service20,21 system, which classifies services into 104 service groups. We present data for five summary service groups in this system: evaluation and management, imaging, major procedures, other procedures, and tests. Major procedures include coronary-artery bypass grafting and hip and knee replacements; other procedures include cataract extraction, colonoscopy and other endoscopic procedures, and routine dermatologic procedures. We identified the top 10 specialties in terms of their share of Medicare spending for physicians' services in 2002. These 10 specialties accounted for more than 70% of Medicare spending for physicians: internal medicine, family practice, cardiology, ophthalmology, diagnostic radiology, orthopedics, general surgery, dermatology, urology, and gastroenterology.
For our analyses, we assigned each service code to one of four hierarchical groups according to the review status: new codes (i.e., codes present in 2002 claims but not in 1992 claims), codes in one or both 5-year reviews, codes in annual reviews, and codes not yet reviewed. New codes represent both new services and services replacing previous procedures or techniques. Without this hierarchy, 10% of the codes would fall into multiple groups.
Results
During the first decade that the resource-based relative-value scale was used, the overall RVU volume per beneficiary for physicians' work grew by 50% (Table 1). The RVU volume per beneficiary grew more slowly for evaluation and management services (39.5%) but grew more rapidly for imaging (62.5%), other procedures (68.2%), and tests (184.8%, from a very small value in 1992). The share of the RVU volume that was accounted for by evaluation and management services decreased by 4.2 percentage points over the decade, whereas the shares for imaging, other procedures, and tests increased (Table 1).
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The relative importance of these components varied among the three service types. Growth in the volume of RVUs per beneficiary for imaging work was due mainly to the growth in the quantity and mix of services (38.4%). Growth in the RVUs for major procedures was due mainly to new service codes (35.6%). Finally, growth in the RVUs for tests was due mainly to revisions in the valuations of the RVUs (68.2%).
In general, growth in the volume of total RVUs was similar to growth in the volume of RVUs for physicians' work, but there was less variation among service types (Table 1). The differences between growth in the volume of RVUs for physicians' work and total RVUs were due mainly to the introduction of resource-based RVUs for practice expenses and professional-liability insurance. This change lowered the total RVUs for many services, which offset some of the growth in the volume of RVUs for physicians' work. Consequently, the growth in the total RVU volume due to revisions in the valuation of RVUs was only 7.6%. The revisions in the valuation of RVUs for practice expenses and professional-liability insurance resulted in a decrease in the total RVU volume for imaging (–6.9%), major procedures (–14.7%), and other procedures (–1.1%).
Changes in the RVU volume for physicians' work and the total volume per beneficiary varied among the top 10 specialties (Table 2). Cardiology had the largest overall growth in the RVU volume for physicians' work (113.6%), whereas urology had a decrease in the RVU volume (–1.0%). Three specialties in particular exhibited substantial growth in the RVU volume for physicians' work due to the quantity and mix of services: cardiology (52.0%), dermatology (41.4%), and gastroenterology (49.4%). Revisions in the valuation of RVUs were the leading sources of growth in the RVU volume for physicians' work in internal medicine (20.1%) and general surgery (23.8%).
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To further understand the sources of growth in the RVU volume for physicians' work, we examined the distribution of service codes and the RVU volume for physicians' work according to the review activity of the CMS and the Relative Value Update Committee (Figure 1). The service codes examined during these comprehensive reviews accounted for only 23% of all the codes, but they accounted for 66% of the RVU volume of physicians' work. Given the influence of the comprehensive reviews, we examined them closely. During the first 5-year review, values for physicians' work were increased for only 30.6% of the service codes, but these codes accounted for 82.0% of the RVU volume for physicians' work under review (Table 3). During the second 5-year review, the values of RVUs increased for a large share of codes (55.7%), but this increase accounted for a smaller share of the RVU volume for physicians' work under review (38.0%). In both 5-year reviews, relatively few codes were reduced in value (10.9% during the first review and 3.6% during the second review).
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Our findings show that the volume of physicians' services per Medicare beneficiary grew considerably during the first decade after the resource-based relative-value scale was introduced. This growth varied among services and specialties and resulted in a redistribution of the total RVU volume (a close counterpart to Medicare spending on physicians). We examined the role of three key factors affecting growth in the RVU volume per beneficiary: increases in the quantity and mix of existing services, revisions of the valuation of RVUs for existing codes, and the introduction of new codes. In terms of the total RVU volume per beneficiary, the volume of imaging services increased the most because of a dramatic increase in the quantity and mix of services. Among all services, the volume of major procedures increased the least, with the introduction of new codes (both to represent new services and to replace previous procedures) accounting for most of the growth. Because of these growth patterns, imaging services gained a greater share of the distribution of total RVU volume. The share of total RVU volume accounted for by evaluation and management services remained the same because of increases in the valuation of RVUs for physicians' work in these services and introduction of resource-based RVUs for practice expenses and professional-liability insurance, which offset the declining relative volume.
In terms of work volume, values for the majority of services (84%) in 2002 reflect a combination of new, reviewed, and revised service codes, rather than the values from the original resource-based relative-value scale. The share of volume affected by these changes in service codes increased in January 2007, when CMS implemented changes based on its third 5-year review of RVUs for physicians' work. That review, which was conducted in 2006, focused on high-frequency service codes that had not been reviewed before and on another review of codes for evaluation and management.22 The Medicare Payment Advisory Commission recently described weaknesses in the 5-year review process for valuing physicians' work and proposed improvements to the process for addressing potentially overvalued codes.23,24 A major concern was the lack of a mechanism for identifying and correcting overvalued services. The commission's view was that the RVUs for physicians' work in providing any service should be reduced if the level of work effort needed to furnish the service declines as physicians gain experience with the service.
We did not explicitly examine the relationship between changes in the supply of physicians and the services provided. However, we analyzed external data on changes in the number of physicians and concluded that the relative growth in the number of physicians among the 10 specialties in this analysis does not track directly with the growth in the total RVU volume or RVUs for physicians' work.25,26,27 For example, the three specialties with the greatest increases in the numbers of physicians — family practice, gastroenterology, and internal medicine — are not the three specialties with the greatest growth in the volume of RVUs for physicians' work and the total RVU volume — dermatology, cardiology, and orthopedics.
A potential limitation of our study is that it measured what occurred during the first 10 years of the fee schedule and does not reflect more recent data and policy developments. However, we think that current policy developments and trends reinforce our findings. For example, although the CMS recently announced that the RVUs for physicians' work associated with certain higher-level evaluation and management codes increased by 29 to 37% (as a result of the third 5-year review), the overall effect of these changes on evaluation and management services was significantly smaller for two reasons.28 First, many other values for evaluation and management services were not increased under the third 5-year review, and second, the CMS reduced all RVUs for physicians' work by 10% as a budget-neutrality adjustment. Furthermore, RVUs for physicians' work account for only about half of the total RVUs. These factors dilute the effect of the increases in evaluation and management services, and the CMS estimated that this year, internists and family physicians, for example, will each receive only a 5% increase in payments as a result of the increases from the third 5-year review.29
Furthermore, our findings suggest that new service codes have a strong influence on the growth and distribution of RVUs for physicians' work and total RVU volume. This influence may be increasing, since new codes continue to be introduced. Since 2002, approximately 800 codes have been added to the Medicare fee schedule, and about 275 existing codes have been deleted; the total number of codes for which RVUs are determined now approaches 7000.30 Finally, our findings show that the RVU volume has grown at different rates among service types. The overall patterns we identified have continued. Most recently, imaging has been the fastest-growing service type, followed by other procedures and tests, whereas the volume of evaluation and management services and the volume of major procedures have grown much more slowly.31
Recent trends and policy decisions overall are consistent with our findings and reinforce the importance of understanding the roles of new service codes, revised valuation of RVUs, and the quantity and mix of services in the growth and distribution of the volume of physicians' services and, by extension, payments. Furthermore, as long as the sustainable growth rate that controls the aggregate growth in spending remains in place, Medicare payment to physicians is essentially a zero-sum game. Thus, differences in rates of growth in the RVU volume of physicians' work and the total RVU volume among service types and specialties affect the overall costs to Medicare, and they should be considered in policies to control Medicare spending.
Supported by the Medicare Payment Advisory Commission and the Urban Institute.
No potential conflict of interest relevant to this article was reported.
The opinions expressed herein are those of the authors and do not necessarily reflect those of the Medicare Payment Advisory Commission or the Urban Institute, its trustees, or its sponsors.
Source Information
From the Urban Institute, Washington, DC.
References
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