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Percutaneous Abscess Drainage: Use of Related Radiology Services and Associated Economic Impact on a Radiology Practice
Percutaneous Abscess Drainage: Use of Related Radiology Services and Associated Economic Impact on a Radiology Practice Richard Duszak, Jr, MD, and Andrew B. Harris, MD, PhD
PURPOSE: To evaluate the impact of percutaneous abscess drainage on the usage and professional value of subsequent services provided by a radiology practice. MATERIALS AND METHODS: Percutaneous abscess drainage was selected as a marker interventional radiology procedure because of its pervasiveness and ease of identification of related services. Billing records were reviewed for 48 consecutive patients who underwent abscess drainage during a 9-month period. Current procedural terminology (CPT) codes for all radiology services during the subsequent 90 days were analyzed to identify those related to the initial drainage procedure. Professional relative value unit (RVU) impact was calculated. RESULTS: Initial abscess drainage services were identified by 2.6 ⴞ 1.2 CPT codes, but patients underwent 13.4 ⴞ 10.7 related radiology services during the subsequent 90 days. The professional RVU impact of subsequent services was 64% higher than that of initial procedures: initial drainage services accounted for 11.5 ⴞ 5.1 RVUs and all subsequent related radiology services accounted for 18.9 ⴞ 16.8 RVUs (P ⴝ .0042). Of those, additional interventional radiology procedures amounted to 10.7 ⴞ 12.8 RVUs, diagnostic radiology services 4.7 ⴞ 4.6 RVUs, and evaluation and management services 3.5 ⴞ 2.9 RVUs. CONCLUSION: Basic interventional radiology services may result in far more economic impact on radiology practices than initial direct procedure analyses suggest. For percutaneous abscess drainage, the professional RVU impact of subsequent services exceeds that of the initial procedure by 64%. Practices negotiating capitated contracts for interventional services need to consider the high value of such related services. J Vasc Interv Radiol 2003; 14:597– 601 Abbreviations:
Current procedural terminology (CPT), relative value unit (RVU), evaluation and management (E&M)
SINCE its introduction more than two decades ago, percutaneous drainage has revolutionized the treatment of abdominal and pelvic abscesses and is now used in an expanded range of anatomical and clinical scenarios (1– 3). Although never compared with
From the Departments of Radiology (R.D.) and Medicine (A.B.H.), The Reading Hospital and Medical Center, PO Box 16052, Sixth and Spruce Streets, Reading, Pennsylvania 19612-6052. Received January 12, 2003; accepted January 15. Presented at the 2002 SCVIR Annual Meeting. Address correspondence to R.D.; E-mail: [email protected] Neither of the authors have identified a potential conflict of interest. © SIR, 2003 DOI: 10.1097/01.RVI.0000071100.54370.DA
open surgical drainage in a controlled prospective trial, percutaneous drainage has become widely accepted by the medical community and is performed with great frequency by interventional radiologists in the academic and community hospital settings alike. Paralleling this growth is the growth of numerous other interventional radiology procedures and ongoing strategic planning for interventional radiologists to develop more clinically oriented practices (4). As interventional radiology so evolves as a distinct subspecialty from diagnostic radiology (5), radiology groups will need to assess the clinical, political and economic impact of how interventional radiology is practiced in their communities. As one component of
their economic analysis, practices will need to understand the financial impact of both basic and complex interventional services on subsequent physician work in the interventional radiology section and in the radiology department as a whole. Because of their intensity and complexity, interventional radiology services have a disproportionately high impact on the total relative value units (RVUs) of service generated by a radiology group (6,7). By calculating the RVU for services provided, the direct economic impact of interventional radiology procedures is thus easily measured. However, the RVU impact of related subsequently generated services is unknown. Such usage impact data would be useful to groups mak-
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ing decisions regarding the feasibility of expanding their interventional program to other facilities. In addition, such information is critical for practices negotiating capitated contracts that include interventional radiology services. The need for ancillary interventional and diagnostic radiology services after percutaneous abscess drainage is well established (8). Most patients undergoing percutaneous abscess drainage will undergo subsequent catheter contrast injections and computed tomography (CT) imaging. Others will need additional drainage procedures or catheter exchanges. In clinically oriented practices, patients will also receive evaluation and management (E&M) services by the treating interventionalists. For newer and more complex procedures, such as aortic endografts, the total RVU impact of subsequent related services in the radiology department is high (9). To the authors’ knowledge, the RVU impact of more basic interventional radiology services has not been evaluated. The goal of this analysis is to assess the economic impact of percutaneous abscess drainage on a radiology practice, with respect to usage and RVU implications of initial drainage procedures and related necessary subsequent services.
METHODS The study methodology was reviewed administratively by the medical center’s institutional review board, which determined that a formal protocol application was not necessary. Six surgical current procedural terminology (CPT) codes were selected as those typical of percutaneous abscess drainage performed by interventional radiologists (Table 1). Using proprietary billing software created for physician claims processing, all patient encounters involving CPT code 75989 (radiologic guidance, for percutaneous drainage, with placement of catheter) and one of these surgical CPT codes during a consecutive 9-month period in the year 2000 were identified. Provisional CPT coding for all procedures was performed at the time of drainage by the operating physician and later reviewed by one of two experienced interventional radiology physician coders who then as-
Table CPT Codes Identified for Percutaneous Abscess Drainage of the Abdomen and Pelvis Code
Description
47011
Hepatotomy; for percutaneous drainage of abscess or cyst, one or two stages Drainage of peritoneal abscess or localized peritonitis, exclusive of appendiceal abscess; percutaneous Drainage of subdiaphragmatic or subphrenic abscess; percutaneous Drainage of retroperitoneal abscess; percutaneous Drainage of perirenal or renal abscess; percutaneous Drainage of pelvic abscess, transvaginal or transrectal approach, percutaneous
49021
49041 49061 50021 58823
Note.—Five-digit CPT codes and descriptions are © 2002 by the American Medical Association.
signed the final CPT codes used by the billing office. Both physician coders had extensive experience in interventional radiology CPT coding and had served as faculty members of coding educational programs sponsored by the Society of Interventional Radiology. Physician coders adhered to the descriptors and rules outlined by the American Medical Association (10) in its CPT 2000 publication and followed coding recommendations published by the Society of Interventional Radiology (11) in its then-current coding guide. All initial drainage services were performed by one of five fellowshiptrained interventional radiologists who practiced in a 19-physician radiology group at a 758-bed community teaching hospital. Abscesses were drained with fluoroscopic, sonographic, or CT guidance as deemed appropriate by the operating physician. Follow-up interventional procedures, imaging studies, and clinical care were performed without specific protocol, as deemed medically necessary by the treating physician(s). The billing software was subsequently interrogated to identify all additional billable encounters with the radiology group during the 90 days after percutaneous abscess drainage.
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Ninety days was selected as the postprocedural service window as it reflects the Medicare (12) global surgical period for most major procedures and represented the postprocedural global surgical period for percutaneous abscess drainage until the recent redefinition and revaluation of this family of CPT codes (13). All identified services and pertinent claims documentation (including physician orders, diagnosis information, and radiology procedure reports) were reviewed by individuals who were at the time members of the Department of Medicine (A.B.H.) and the Section of Interventional Radiology (R.D.). Subsequent services related to the initial percutaneous abscess drainage procedure or the condition that necessitated that initial drainage procedure were chosen from the list of all billable services by consensus review. All selected CPT services were then categorized as i) initial drainage procedures, ii) subsequent interventional radiology procedures, iii) subsequent diagnostic radiology services, or iv) clinical E&M services, and all incorporated into a spreadsheet data base created specifically for this analysis (Microsoft Excel, Microsoft, Redmond, WA). The total professional relative value unit (RVU) was used as a marker of the economic impact of all identified services, as it reasonably parallels physician reimbursement and is not subject to payer-to-payer variation (14). RVUs for all services are published annually (12), and also available in electronic form from the Centers for Medicare and Medicaid Services (15). A spreadsheet lookup algorithm (Microsoft Excel, Microsoft, Redmond WA) and a complete electronic CPT RVU database for the year 2000 (15) were used to calculate an aggregated RVU for each patient and determine category of service. Because the intent was to measure the RVU impact of the initial and subsequent professional services (rather than the impact of physician services on hospital reimbursement), only the professional portion of RVU was used for codes that were separately or in combined form valued for their professional and technical components. For surgical codes, the total published facility RVU was used. For radiological supervision and interpretation codes, only the modifi-
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er-26 professional portion was used. RVU was computed for all services, and the RVU impact for all patients and categories of services was calculated by multiplying the frequency of the service by the total professional component of RVU (14): RVU impact ⫽ (frequency of code) ⫻ (RVU of code). Service frequency and RVU impact were analyzed and compared. To determine whether patient age may affect the economic impact of services related to percutaneous abscess drainage, these analyses were performed separately for patients less than 65 years of age (typically insured by private payers) and those 65 years of age and older (typically Medicare beneficiaries). Statistical analysis was performed using the Student t test. To benchmark interventional radiology clinical services with those provided by other practices nationwide, a separate analysis was performed to assess the frequency and RVU impact of E&M encounters with respect to all services provided by the interventional radiology section (ie, not just those associated with percutaneous abscess drainage). A similar methodology for extraction of CPT data from claims records was used to analyze 12 months of billing data for each of the group’s five interventionalists to identify the frequency and RVU impact of all services provided. E&M-specific data were subsequently extracted from the aggregate data and used to assess the frequency and contribution of E&M services to all reimbursable physician work.
RESULTS Initial percutaneous abscess drainage was performed on 63 collections in 48 patients. Seven of those patients (15%) underwent a total of 11 subsequent drainage procedures. Patients ranged in age from 23 to 99 years (mean, 60 ⫾ 18) and included 26 men and 22 women. Collectively, 768 CPT defined services were identified for drainage procedures and related services provided by the radiology practice, corresponding to 1,445 RVUs. Initial percutaneous abscess drainage procedures were designated by 2.6 ⫾ 1.2 CPT service codes (range, 2– 6). Initial drainage procedures were most
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commonly performed on peritoneal abscesses (CPT 49021, n ⫽ 31) and retroperitoneal abscesses (CPT 49061, n ⫽ 11). During the 90 days after initial abscess drainage, patients underwent a mean 13.4 ⫾ 10.7 (range, 1– 45) CPT defined services by members of the radiology department. These included 6.9 ⫾ 7.2 (range, 0 –32) subsequent related interventional services, 2.9 ⫾ 2.9 (range, 0 –14) diagnostic radiology procedures, and 3.5 ⫾ 3.0 (range, 0 –11) E&M services. The per-patient economic impact of initial percutaneous abscess drainage was 11.5 ⫾ 5.1 RVUs (range, 8.0 –29.0). Subsequent interventional radiology procedures amounted to 10.7 ⫾ 12.8 RVUs (range, 0 – 47.3) and were performed in 38 of 48 patients (79%). These procedures included 0.5 ⫾ 1.2 subsequent abscess drainage services in seven patients (15%) and 6.5 ⫾ 6.8 other related interventional radiology services in 38 patients (79%). The latter category most commonly included catheter contrast injections (CPT 49424, n ⫽ 103) and catheter exchange procedures (CPT 49423, n ⫽ 8). Subsequent drainage procedures amounted to a mean 2.1 ⫾ 5.3 RVUs, and the other related interventional radiology services amounted to 8.6 ⫾ 10.7 RVUs. Related diagnostic radiology services were performed in 39 patients (81%). These averaged 2.9 ⫾ 2.9 services per patient, and corresponded to 4.7 ⫾ 4.6 RVUs. Most frequently, these services were for CT of the pelvis with intravenous contrast material (CPT 72193, n ⫽ 50), the abdomen with contrast material (CPT 74160, n ⫽ 44), the pelvis without contrast material (CPT 72192, n ⫽ 18), and the abdomen without contrast material (CPT 74150, n ⫽ 15). Billable clinical services were provided to 44 patients (92%). Each patient had a mean 3.5 ⫾ 3.0 E&M encounters, corresponding to 3.5 ⫾ 2.9 RVUs. In all but one instance, these were for follow-up hospital care after abscess drainage (CPT code 99231). The total professional value of all subsequent services by the radiology group was 64% higher than that of the initial drainage procedures themselves (18.9 ⫾ 16.8 versus 11.5 ⫾ 5.1; P ⫽ .0042). Of patients treated with percutaneous abscess drainage, 29 were less
•
599
than 65 years of age and 19 were more than 65 years of age. The total number of CPT-defined services provided to younger patients was similar to that of older patients (16.1 ⫾ 10.9 versus 15.8 ⫾ 11.2; P ⫽ .92). Also similar was the economic impact of abscess drainage services in both groups (31.0 ⫾ 17.9 versus 29.4 ⫾ 19.2 RVUs; P ⫽ .73). In the separate benchmarking analysis of clinical services performed by the practice’s five interventional radiologists during a 12-month period, a total of 47,804 CPT-defined services were identified (mean, 9,561 per physician; range, 8,068 –11,267). Associated aggregate RVUs were 60,200 (mean, 12,040 per physician; range, 8,525–14,209). Of these, E&M encounters totaled 1,005 (mean, 201 per physician; range, 157–318), with associated RVUs of 1,105 (mean, 221 per physician; range, 173–354). E&M services overall thus accounted for 2.1% of all billable services performed by the practice’s interventional radiologists, and for 1.8% of their total RVUs.
DISCUSSION Based on this experience, percutaneous abscess drainage ultimately results in far more economic impact on a radiology practice than a simple initial direct procedural analysis would suggest. In fact, the total professional RVU impact of percutaneous abscess drainage is 264% of the initial drainage procedure itself. As interventional radiology carries out its strategic new vision (4), the potential for conflict will undoubtedly exist as many increasingly clinically oriented interventionalists continue to practice under the umbrella of traditional diagnostic radiology practices. Those groups will appropriately scrutinize the administrative, political, and economic implications of such arrangements. With regard to the latter, the burden may be placed on interventional radiologists to defend the value of their services to the organization at large. In stating their case, interventionalists will need to demonstrate not only the direct economic value of the services they offer, but the indirect value of those services as well. A complete indirect economic impact analysis is complex and beyond the scope of this study, and would need to account for complex and difficult to measure
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variables such as physician efficiency overall and physician productivity when providing diagnostic versus interventional radiology services. Nonetheless, an understanding of the impact of any given interventional service on the usage and relative value of subsequently generated services will provide some insight into the overall professional economic impact of that service on a practice. To that end, based on this experience with percutaneous abscess drainage, a simple ratio is proposed—the subsequent service index factor (SSIF)—that may be of help in such analyses: SSIF ⫽ (total RVU of subsequent services) ⫼ (RVU of initial services). For percutaneous abscess drainage, the SSIF ⫽ 1.64. The outlined methodology can be used to generate a similar ratio for other interventional radiology services. For procedures such as percutaneous gastrostomy tube placement, where subsequent related radiology services are uncommon (16,17), the predicted SSIF would be small. For services such as tunneled hemodialysis catheter salvage procedures, where postprocedural device patency is often limited (18,19,20), the SSIF would likely be much higher. Although this ratio would vary greatly for different procedures, and even for the same procedure performed in different communities, it may serve as a benchmark to help practices assess at least part of the financial impact of specific types of interventional radiology services. This assessment will be important for practices offering new services, those expanding existing services into new hospitals and communities, and in particular, those placed in the difficult situation of negotiating capitated insurance contracts that do not permit interventional radiology “carve-outs.” Such a calculation might also be helpful to interventionalists defending the value of an outpatient clinic to their diagnostic radiology partners. Consultations on patients with peripheral vascular disease, uterine fibroids, and hepatic malignancies, for example, generate little direct economic impact on a practice, but are necessary prerequisites to that practice being able to provide appropriate complex and relatively highly-
valued interventional procedures and related diagnostic services. Like any economic model for a medical service, the one used in this study for percutaneous abscess drainage is imperfect and necessarily simplified. For example, it does not account for the methodical but skilled interventionalist who more efficiently interprets cross-sectional imaging studies or for the opportunity cost of stalling diagnostic CT throughput during a prolonged and difficult drainage procedure. Providing the best quality medical care may not always be economically advantageous. Additionally, this model is based on CPT coding, which is erroneous in up to 25% of interventional radiology procedures (14) and 50% of clinical E&M encounters (21,22) when coding is performed by physicians. Since the examined practice has implemented an advocated two-level CPT code review for all its interventional services (14), the accuracy of CPT coding is as high as practically possible. However, because overcoding errors and undercoding errors essentially negate each other economically for E&M services (22) and for interventional radiology services that use the described coding quality assurance model (14), the ramifications of CPT coding errors, if present, would be small. The ultimate impact of percutaneous abscess drainage on subsequent radiology services may be highly dependent on the individual treating interventional radiologist, other attending physicians, the local medical community, and the overall level of acuity of the typical treated patient. This is a single institutional analysis and may not reflect the style of care provided in all other settings. For example, in this abscess drainage experience, E&M encounters for percutaneous abscess drainage amounted to 11.4% of total professional RVUs. At first glance, this suggests more intensive clinical care than the 0.5% figure recently reported from national Medicare data (23). However, in the examined practice, E&M encounters amounted to 2.1% of all services provided by interventional radiologists and 1.8% of their RVUs, which are much closer to national benchmarks of 0.4% and 0.5%, respectively (23). The discrepancy between 1.8% and 11.4% of RVU for E&M confirms the obvious:
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abscess drainage services inherently require more intense clinical follow-up than many other services provided by interventionalists (such as diagnostic angiography and central venous access procedures). Unlike a previous analysis of abdominal aortic aneurysms, which compared the economic impact of endovascular versus conventional open surgical repair (9), the economic impact on a radiology practice of open surgical abscess drainage was not evaluated in this study. Given the widespread acceptance of percutaneous abscess drainage by the medical community and the relative infrequency with which open drainage is performed, this specific question will likely never be adequately answered. However, from a practical perspective, the question is believed to be moot. In the few hospitals where percutaneous abscess drainage is not available, most patients will likely be offered transfer to institutions that offer these services— institutions whose radiology practices will then see the described usage and associated economic ramifications. Like any economic analysis, this study only addresses the very specific parameter evaluated—the impact of percutaneous drainage on subsequent services provided by a radiology practice. Not evaluated as part of this analysis are the economic impact of such services on a hospital or insurer or the overall cost-effectiveness of such services. These are important and related questions that can only be answered with separate dedicated studies. In summary, in addition to its important clinical impact, percutaneous abscess drainage has a significant and disproportionate impact on subsequent services provided by a radiology practice. Many other interventional radiology procedures likely have a significant impact on subsequent radiology services, as well. As interventional radiologists forge ahead as clinical specialists, future investigation will be necessary to more fully demonstrate the ultimate economic impact of their services on the groups in which they practice. Acknowledgments: The authors thank Larry Johnson and his staff from Medical Billing and Management Services for performing the software interrogation and billing record review that made this analysis possible and Michael Mabry of the
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Society of Interventional Radiology and Dr. Brent Wagner of West Reading Radiology Associates for their insightful and thoughtful comments. References 1. Gerzof SG, Robbins AH, Johnson WC, Burkette DH, Nasbeth DC. Percutaneous catheter drainage of abdominal abscesses: a five-year experience. N Engl J Med 1981; 305:653– 657. 2. vanSonnenberg E, D’Agostino HB, Casola G, Halasz NA, Sanchez RB, Goodacre BW. Percutaneous abscess drainage: current concepts. Radiology 1991; 181:617– 626. 3. vanSonnenberg E, Wittich GR, Goodacre BW, Casola G, D’Agostino HB. Percutaneous abscess drainage: update. World J Surg 2001; 25:362–372. 4. Bakal CW, Darcy MD, Brunner MC, Pomerantz P. Strategic initiatives in interventional radiology: a new vision. J Vasc Interv Radiol 2002; 13:559 –562. 5. American College of Radiology. ACR Annual Meeting. ACR Bulletin 1999; 1999; 55:33– 40. 6. Conoley PM, Vernon SW. Productivity of radiologists: estimates based on analysis of relative value units. AJR Am J Roentgenol 1991; 157:1337–1340. 7. Sunshine JH, Burkhardt JH. Radiology groups’ workload in relative value units and factors affecting it. Radiology 2000; 214:815– 822. 8. Lambiase RE, Deyoe L, Cronan JJ, Dorfman GS. Percutaneous drainage of 335 consecutive abscesses: results of primary drainage with 1-year followup. Radiology 1992; 184:167–179.
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9. Baum RA, Tuite CM, Soulen MC, et al. Economic impact of an abdominal aortic stent graft program on a radiology department. Radiology 1999; 213(P):433. 10. American Medical Association. Current Procedural Terminology (CPT) 2000. Chicago: American Medical Association, 1999. 11. Society of Cardiovascular and interventional Radiology. SCVIR Interventional Radiology Coding Users’ Guide. 6th ed. Fairfax, VA: SCVIR, 2000. 12. Health Care Financing Agency. Medicare program; revision to payment policies under the physician fee schedule for calendar year 2000; final rule. Federal Register 1999; 64:59443– 59582. 13. American Medical Association. Current Procedural Terminology 1998. Chicago: American Medical Association, 1997. 14. Duszak R, Sacks D, Manowczak J. CPT coding by interventional radiologists: accuracy and implications. J Vasc Interv Radiol 2001; 12:447– 454. 15. Centers for Medicare and Medicaid Services. Physician fee schedule. Available at http://cms.hhs.gov/physicians/pfs/ default.asp. Accessed August 2002: 14. 16. deBaere T, Chapot R, Kuoch V, et al. Percutaneous gastrostomy with fluoroscopic guidance: single-center experience in 500 consecutive cancer patients. Radiology 1999; 210:651– 654. 17. Dewald CL, Hiette PO, Sewall LE, Fredenberg PG, Palestrant AM. Percutaneous gastrostomy and gastrojejunostomy with gastropexy: experience in
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701 procedures. Radiology 1999; 211: 651– 656. Gray RJ, Levitin A, Buck D, et al. Percutaneous fibrin sheath stripping versus transcatheter urokinase infusion for malfunctioning well-positioned tunneled central venous dialysis catheters: a prospective, randomized trial. J Vasc Interv Radiol 2000; 11:1121–1129. Merport M, Murphy TP, Egglin TK, Dubel GJ. Fibrin sheath stripping versus catheter exchange for the treatment of failed tunneled hemodialysis catheters: randomized clinical trial. J Vasc Interv Radiol 2000; 11:1115–1120. Savader SJ, Ehrman KO, Porter DJ, Haikal LC, Oteham AC. Treatment of hemodialysis catheter-associated fibrin sheaths by rt-PA infusion: critical analysis of 124 procedures. J Vasc Interv Radiol 2001; 12:711–715. King MS, Sharp L, Lipsky MS. Accuracy of CPT evaluation and management coding by family physicians. J Am Board Fam Pract 2001; 14:184 – 192. Chao J, Gillanders WG, Flocke SA, Goodwin MA, Kikano GE, Stange KC. Billing for physician services: a comparison of actual billing with CPT codes assigned by direct observation. J Fam Pract 1998; 47:28 –32. Duszak R, Mabry MR. Clinical Services in interventional radiology: results from the national Medicare database and a Society of Interventional Radiology membership survey. J Vasc Interv Radiol 2003; 13:75– 81.
PURPOSE: To evaluate the impact of percutaneous abscess drainage on the usage and professional value of subsequent services provided by a radiology practice. MATERIALS AND METHODS: Percutaneous abscess drainage was selected as a marker interventional radiology procedure because of its pervasiveness and ease of identification of related services. Billing records were reviewed for 48 consecutive patients who underwent abscess drainage during a 9-month period. Current procedural terminology (CPT) codes for all radiology services during the subsequent 90 days were analyzed to identify those related to the initial drainage procedure. Professional relative value unit (RVU) impact was calculated. RESULTS: Initial abscess drainage services were identified by 2.6 ⴞ 1.2 CPT codes, but patients underwent 13.4 ⴞ 10.7 related radiology services during the subsequent 90 days. The professional RVU impact of subsequent services was 64% higher than that of initial procedures: initial drainage services accounted for 11.5 ⴞ 5.1 RVUs and all subsequent related radiology services accounted for 18.9 ⴞ 16.8 RVUs (P ⴝ .0042). Of those, additional interventional radiology procedures amounted to 10.7 ⴞ 12.8 RVUs, diagnostic radiology services 4.7 ⴞ 4.6 RVUs, and evaluation and management services 3.5 ⴞ 2.9 RVUs. CONCLUSION: Basic interventional radiology services may result in far more economic impact on radiology practices than initial direct procedure analyses suggest. For percutaneous abscess drainage, the professional RVU impact of subsequent services exceeds that of the initial procedure by 64%. Practices negotiating capitated contracts for interventional services need to consider the high value of such related services. J Vasc Interv Radiol 2003; 14:597– 601 Abbreviations:
Current procedural terminology (CPT), relative value unit (RVU), evaluation and management (E&M)
SINCE its introduction more than two decades ago, percutaneous drainage has revolutionized the treatment of abdominal and pelvic abscesses and is now used in an expanded range of anatomical and clinical scenarios (1– 3). Although never compared with
From the Departments of Radiology (R.D.) and Medicine (A.B.H.), The Reading Hospital and Medical Center, PO Box 16052, Sixth and Spruce Streets, Reading, Pennsylvania 19612-6052. Received January 12, 2003; accepted January 15. Presented at the 2002 SCVIR Annual Meeting. Address correspondence to R.D.; E-mail: [email protected] Neither of the authors have identified a potential conflict of interest. © SIR, 2003 DOI: 10.1097/01.RVI.0000071100.54370.DA
open surgical drainage in a controlled prospective trial, percutaneous drainage has become widely accepted by the medical community and is performed with great frequency by interventional radiologists in the academic and community hospital settings alike. Paralleling this growth is the growth of numerous other interventional radiology procedures and ongoing strategic planning for interventional radiologists to develop more clinically oriented practices (4). As interventional radiology so evolves as a distinct subspecialty from diagnostic radiology (5), radiology groups will need to assess the clinical, political and economic impact of how interventional radiology is practiced in their communities. As one component of
their economic analysis, practices will need to understand the financial impact of both basic and complex interventional services on subsequent physician work in the interventional radiology section and in the radiology department as a whole. Because of their intensity and complexity, interventional radiology services have a disproportionately high impact on the total relative value units (RVUs) of service generated by a radiology group (6,7). By calculating the RVU for services provided, the direct economic impact of interventional radiology procedures is thus easily measured. However, the RVU impact of related subsequently generated services is unknown. Such usage impact data would be useful to groups mak-
597
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Economic Impact of Percutaneous Abscess Drainage
ing decisions regarding the feasibility of expanding their interventional program to other facilities. In addition, such information is critical for practices negotiating capitated contracts that include interventional radiology services. The need for ancillary interventional and diagnostic radiology services after percutaneous abscess drainage is well established (8). Most patients undergoing percutaneous abscess drainage will undergo subsequent catheter contrast injections and computed tomography (CT) imaging. Others will need additional drainage procedures or catheter exchanges. In clinically oriented practices, patients will also receive evaluation and management (E&M) services by the treating interventionalists. For newer and more complex procedures, such as aortic endografts, the total RVU impact of subsequent related services in the radiology department is high (9). To the authors’ knowledge, the RVU impact of more basic interventional radiology services has not been evaluated. The goal of this analysis is to assess the economic impact of percutaneous abscess drainage on a radiology practice, with respect to usage and RVU implications of initial drainage procedures and related necessary subsequent services.
METHODS The study methodology was reviewed administratively by the medical center’s institutional review board, which determined that a formal protocol application was not necessary. Six surgical current procedural terminology (CPT) codes were selected as those typical of percutaneous abscess drainage performed by interventional radiologists (Table 1). Using proprietary billing software created for physician claims processing, all patient encounters involving CPT code 75989 (radiologic guidance, for percutaneous drainage, with placement of catheter) and one of these surgical CPT codes during a consecutive 9-month period in the year 2000 were identified. Provisional CPT coding for all procedures was performed at the time of drainage by the operating physician and later reviewed by one of two experienced interventional radiology physician coders who then as-
Table CPT Codes Identified for Percutaneous Abscess Drainage of the Abdomen and Pelvis Code
Description
47011
Hepatotomy; for percutaneous drainage of abscess or cyst, one or two stages Drainage of peritoneal abscess or localized peritonitis, exclusive of appendiceal abscess; percutaneous Drainage of subdiaphragmatic or subphrenic abscess; percutaneous Drainage of retroperitoneal abscess; percutaneous Drainage of perirenal or renal abscess; percutaneous Drainage of pelvic abscess, transvaginal or transrectal approach, percutaneous
49021
49041 49061 50021 58823
Note.—Five-digit CPT codes and descriptions are © 2002 by the American Medical Association.
signed the final CPT codes used by the billing office. Both physician coders had extensive experience in interventional radiology CPT coding and had served as faculty members of coding educational programs sponsored by the Society of Interventional Radiology. Physician coders adhered to the descriptors and rules outlined by the American Medical Association (10) in its CPT 2000 publication and followed coding recommendations published by the Society of Interventional Radiology (11) in its then-current coding guide. All initial drainage services were performed by one of five fellowshiptrained interventional radiologists who practiced in a 19-physician radiology group at a 758-bed community teaching hospital. Abscesses were drained with fluoroscopic, sonographic, or CT guidance as deemed appropriate by the operating physician. Follow-up interventional procedures, imaging studies, and clinical care were performed without specific protocol, as deemed medically necessary by the treating physician(s). The billing software was subsequently interrogated to identify all additional billable encounters with the radiology group during the 90 days after percutaneous abscess drainage.
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Ninety days was selected as the postprocedural service window as it reflects the Medicare (12) global surgical period for most major procedures and represented the postprocedural global surgical period for percutaneous abscess drainage until the recent redefinition and revaluation of this family of CPT codes (13). All identified services and pertinent claims documentation (including physician orders, diagnosis information, and radiology procedure reports) were reviewed by individuals who were at the time members of the Department of Medicine (A.B.H.) and the Section of Interventional Radiology (R.D.). Subsequent services related to the initial percutaneous abscess drainage procedure or the condition that necessitated that initial drainage procedure were chosen from the list of all billable services by consensus review. All selected CPT services were then categorized as i) initial drainage procedures, ii) subsequent interventional radiology procedures, iii) subsequent diagnostic radiology services, or iv) clinical E&M services, and all incorporated into a spreadsheet data base created specifically for this analysis (Microsoft Excel, Microsoft, Redmond, WA). The total professional relative value unit (RVU) was used as a marker of the economic impact of all identified services, as it reasonably parallels physician reimbursement and is not subject to payer-to-payer variation (14). RVUs for all services are published annually (12), and also available in electronic form from the Centers for Medicare and Medicaid Services (15). A spreadsheet lookup algorithm (Microsoft Excel, Microsoft, Redmond WA) and a complete electronic CPT RVU database for the year 2000 (15) were used to calculate an aggregated RVU for each patient and determine category of service. Because the intent was to measure the RVU impact of the initial and subsequent professional services (rather than the impact of physician services on hospital reimbursement), only the professional portion of RVU was used for codes that were separately or in combined form valued for their professional and technical components. For surgical codes, the total published facility RVU was used. For radiological supervision and interpretation codes, only the modifi-
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er-26 professional portion was used. RVU was computed for all services, and the RVU impact for all patients and categories of services was calculated by multiplying the frequency of the service by the total professional component of RVU (14): RVU impact ⫽ (frequency of code) ⫻ (RVU of code). Service frequency and RVU impact were analyzed and compared. To determine whether patient age may affect the economic impact of services related to percutaneous abscess drainage, these analyses were performed separately for patients less than 65 years of age (typically insured by private payers) and those 65 years of age and older (typically Medicare beneficiaries). Statistical analysis was performed using the Student t test. To benchmark interventional radiology clinical services with those provided by other practices nationwide, a separate analysis was performed to assess the frequency and RVU impact of E&M encounters with respect to all services provided by the interventional radiology section (ie, not just those associated with percutaneous abscess drainage). A similar methodology for extraction of CPT data from claims records was used to analyze 12 months of billing data for each of the group’s five interventionalists to identify the frequency and RVU impact of all services provided. E&M-specific data were subsequently extracted from the aggregate data and used to assess the frequency and contribution of E&M services to all reimbursable physician work.
RESULTS Initial percutaneous abscess drainage was performed on 63 collections in 48 patients. Seven of those patients (15%) underwent a total of 11 subsequent drainage procedures. Patients ranged in age from 23 to 99 years (mean, 60 ⫾ 18) and included 26 men and 22 women. Collectively, 768 CPT defined services were identified for drainage procedures and related services provided by the radiology practice, corresponding to 1,445 RVUs. Initial percutaneous abscess drainage procedures were designated by 2.6 ⫾ 1.2 CPT service codes (range, 2– 6). Initial drainage procedures were most
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commonly performed on peritoneal abscesses (CPT 49021, n ⫽ 31) and retroperitoneal abscesses (CPT 49061, n ⫽ 11). During the 90 days after initial abscess drainage, patients underwent a mean 13.4 ⫾ 10.7 (range, 1– 45) CPT defined services by members of the radiology department. These included 6.9 ⫾ 7.2 (range, 0 –32) subsequent related interventional services, 2.9 ⫾ 2.9 (range, 0 –14) diagnostic radiology procedures, and 3.5 ⫾ 3.0 (range, 0 –11) E&M services. The per-patient economic impact of initial percutaneous abscess drainage was 11.5 ⫾ 5.1 RVUs (range, 8.0 –29.0). Subsequent interventional radiology procedures amounted to 10.7 ⫾ 12.8 RVUs (range, 0 – 47.3) and were performed in 38 of 48 patients (79%). These procedures included 0.5 ⫾ 1.2 subsequent abscess drainage services in seven patients (15%) and 6.5 ⫾ 6.8 other related interventional radiology services in 38 patients (79%). The latter category most commonly included catheter contrast injections (CPT 49424, n ⫽ 103) and catheter exchange procedures (CPT 49423, n ⫽ 8). Subsequent drainage procedures amounted to a mean 2.1 ⫾ 5.3 RVUs, and the other related interventional radiology services amounted to 8.6 ⫾ 10.7 RVUs. Related diagnostic radiology services were performed in 39 patients (81%). These averaged 2.9 ⫾ 2.9 services per patient, and corresponded to 4.7 ⫾ 4.6 RVUs. Most frequently, these services were for CT of the pelvis with intravenous contrast material (CPT 72193, n ⫽ 50), the abdomen with contrast material (CPT 74160, n ⫽ 44), the pelvis without contrast material (CPT 72192, n ⫽ 18), and the abdomen without contrast material (CPT 74150, n ⫽ 15). Billable clinical services were provided to 44 patients (92%). Each patient had a mean 3.5 ⫾ 3.0 E&M encounters, corresponding to 3.5 ⫾ 2.9 RVUs. In all but one instance, these were for follow-up hospital care after abscess drainage (CPT code 99231). The total professional value of all subsequent services by the radiology group was 64% higher than that of the initial drainage procedures themselves (18.9 ⫾ 16.8 versus 11.5 ⫾ 5.1; P ⫽ .0042). Of patients treated with percutaneous abscess drainage, 29 were less
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than 65 years of age and 19 were more than 65 years of age. The total number of CPT-defined services provided to younger patients was similar to that of older patients (16.1 ⫾ 10.9 versus 15.8 ⫾ 11.2; P ⫽ .92). Also similar was the economic impact of abscess drainage services in both groups (31.0 ⫾ 17.9 versus 29.4 ⫾ 19.2 RVUs; P ⫽ .73). In the separate benchmarking analysis of clinical services performed by the practice’s five interventional radiologists during a 12-month period, a total of 47,804 CPT-defined services were identified (mean, 9,561 per physician; range, 8,068 –11,267). Associated aggregate RVUs were 60,200 (mean, 12,040 per physician; range, 8,525–14,209). Of these, E&M encounters totaled 1,005 (mean, 201 per physician; range, 157–318), with associated RVUs of 1,105 (mean, 221 per physician; range, 173–354). E&M services overall thus accounted for 2.1% of all billable services performed by the practice’s interventional radiologists, and for 1.8% of their total RVUs.
DISCUSSION Based on this experience, percutaneous abscess drainage ultimately results in far more economic impact on a radiology practice than a simple initial direct procedural analysis would suggest. In fact, the total professional RVU impact of percutaneous abscess drainage is 264% of the initial drainage procedure itself. As interventional radiology carries out its strategic new vision (4), the potential for conflict will undoubtedly exist as many increasingly clinically oriented interventionalists continue to practice under the umbrella of traditional diagnostic radiology practices. Those groups will appropriately scrutinize the administrative, political, and economic implications of such arrangements. With regard to the latter, the burden may be placed on interventional radiologists to defend the value of their services to the organization at large. In stating their case, interventionalists will need to demonstrate not only the direct economic value of the services they offer, but the indirect value of those services as well. A complete indirect economic impact analysis is complex and beyond the scope of this study, and would need to account for complex and difficult to measure
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variables such as physician efficiency overall and physician productivity when providing diagnostic versus interventional radiology services. Nonetheless, an understanding of the impact of any given interventional service on the usage and relative value of subsequently generated services will provide some insight into the overall professional economic impact of that service on a practice. To that end, based on this experience with percutaneous abscess drainage, a simple ratio is proposed—the subsequent service index factor (SSIF)—that may be of help in such analyses: SSIF ⫽ (total RVU of subsequent services) ⫼ (RVU of initial services). For percutaneous abscess drainage, the SSIF ⫽ 1.64. The outlined methodology can be used to generate a similar ratio for other interventional radiology services. For procedures such as percutaneous gastrostomy tube placement, where subsequent related radiology services are uncommon (16,17), the predicted SSIF would be small. For services such as tunneled hemodialysis catheter salvage procedures, where postprocedural device patency is often limited (18,19,20), the SSIF would likely be much higher. Although this ratio would vary greatly for different procedures, and even for the same procedure performed in different communities, it may serve as a benchmark to help practices assess at least part of the financial impact of specific types of interventional radiology services. This assessment will be important for practices offering new services, those expanding existing services into new hospitals and communities, and in particular, those placed in the difficult situation of negotiating capitated insurance contracts that do not permit interventional radiology “carve-outs.” Such a calculation might also be helpful to interventionalists defending the value of an outpatient clinic to their diagnostic radiology partners. Consultations on patients with peripheral vascular disease, uterine fibroids, and hepatic malignancies, for example, generate little direct economic impact on a practice, but are necessary prerequisites to that practice being able to provide appropriate complex and relatively highly-
valued interventional procedures and related diagnostic services. Like any economic model for a medical service, the one used in this study for percutaneous abscess drainage is imperfect and necessarily simplified. For example, it does not account for the methodical but skilled interventionalist who more efficiently interprets cross-sectional imaging studies or for the opportunity cost of stalling diagnostic CT throughput during a prolonged and difficult drainage procedure. Providing the best quality medical care may not always be economically advantageous. Additionally, this model is based on CPT coding, which is erroneous in up to 25% of interventional radiology procedures (14) and 50% of clinical E&M encounters (21,22) when coding is performed by physicians. Since the examined practice has implemented an advocated two-level CPT code review for all its interventional services (14), the accuracy of CPT coding is as high as practically possible. However, because overcoding errors and undercoding errors essentially negate each other economically for E&M services (22) and for interventional radiology services that use the described coding quality assurance model (14), the ramifications of CPT coding errors, if present, would be small. The ultimate impact of percutaneous abscess drainage on subsequent radiology services may be highly dependent on the individual treating interventional radiologist, other attending physicians, the local medical community, and the overall level of acuity of the typical treated patient. This is a single institutional analysis and may not reflect the style of care provided in all other settings. For example, in this abscess drainage experience, E&M encounters for percutaneous abscess drainage amounted to 11.4% of total professional RVUs. At first glance, this suggests more intensive clinical care than the 0.5% figure recently reported from national Medicare data (23). However, in the examined practice, E&M encounters amounted to 2.1% of all services provided by interventional radiologists and 1.8% of their RVUs, which are much closer to national benchmarks of 0.4% and 0.5%, respectively (23). The discrepancy between 1.8% and 11.4% of RVU for E&M confirms the obvious:
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abscess drainage services inherently require more intense clinical follow-up than many other services provided by interventionalists (such as diagnostic angiography and central venous access procedures). Unlike a previous analysis of abdominal aortic aneurysms, which compared the economic impact of endovascular versus conventional open surgical repair (9), the economic impact on a radiology practice of open surgical abscess drainage was not evaluated in this study. Given the widespread acceptance of percutaneous abscess drainage by the medical community and the relative infrequency with which open drainage is performed, this specific question will likely never be adequately answered. However, from a practical perspective, the question is believed to be moot. In the few hospitals where percutaneous abscess drainage is not available, most patients will likely be offered transfer to institutions that offer these services— institutions whose radiology practices will then see the described usage and associated economic ramifications. Like any economic analysis, this study only addresses the very specific parameter evaluated—the impact of percutaneous drainage on subsequent services provided by a radiology practice. Not evaluated as part of this analysis are the economic impact of such services on a hospital or insurer or the overall cost-effectiveness of such services. These are important and related questions that can only be answered with separate dedicated studies. In summary, in addition to its important clinical impact, percutaneous abscess drainage has a significant and disproportionate impact on subsequent services provided by a radiology practice. Many other interventional radiology procedures likely have a significant impact on subsequent radiology services, as well. As interventional radiologists forge ahead as clinical specialists, future investigation will be necessary to more fully demonstrate the ultimate economic impact of their services on the groups in which they practice. Acknowledgments: The authors thank Larry Johnson and his staff from Medical Billing and Management Services for performing the software interrogation and billing record review that made this analysis possible and Michael Mabry of the
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Society of Interventional Radiology and Dr. Brent Wagner of West Reading Radiology Associates for their insightful and thoughtful comments. References 1. Gerzof SG, Robbins AH, Johnson WC, Burkette DH, Nasbeth DC. Percutaneous catheter drainage of abdominal abscesses: a five-year experience. N Engl J Med 1981; 305:653– 657. 2. vanSonnenberg E, D’Agostino HB, Casola G, Halasz NA, Sanchez RB, Goodacre BW. Percutaneous abscess drainage: current concepts. Radiology 1991; 181:617– 626. 3. vanSonnenberg E, Wittich GR, Goodacre BW, Casola G, D’Agostino HB. Percutaneous abscess drainage: update. World J Surg 2001; 25:362–372. 4. Bakal CW, Darcy MD, Brunner MC, Pomerantz P. Strategic initiatives in interventional radiology: a new vision. J Vasc Interv Radiol 2002; 13:559 –562. 5. American College of Radiology. ACR Annual Meeting. ACR Bulletin 1999; 1999; 55:33– 40. 6. Conoley PM, Vernon SW. Productivity of radiologists: estimates based on analysis of relative value units. AJR Am J Roentgenol 1991; 157:1337–1340. 7. Sunshine JH, Burkhardt JH. Radiology groups’ workload in relative value units and factors affecting it. Radiology 2000; 214:815– 822. 8. Lambiase RE, Deyoe L, Cronan JJ, Dorfman GS. Percutaneous drainage of 335 consecutive abscesses: results of primary drainage with 1-year followup. Radiology 1992; 184:167–179.
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9. Baum RA, Tuite CM, Soulen MC, et al. Economic impact of an abdominal aortic stent graft program on a radiology department. Radiology 1999; 213(P):433. 10. American Medical Association. Current Procedural Terminology (CPT) 2000. Chicago: American Medical Association, 1999. 11. Society of Cardiovascular and interventional Radiology. SCVIR Interventional Radiology Coding Users’ Guide. 6th ed. Fairfax, VA: SCVIR, 2000. 12. Health Care Financing Agency. Medicare program; revision to payment policies under the physician fee schedule for calendar year 2000; final rule. Federal Register 1999; 64:59443– 59582. 13. American Medical Association. Current Procedural Terminology 1998. Chicago: American Medical Association, 1997. 14. Duszak R, Sacks D, Manowczak J. CPT coding by interventional radiologists: accuracy and implications. J Vasc Interv Radiol 2001; 12:447– 454. 15. Centers for Medicare and Medicaid Services. Physician fee schedule. Available at http://cms.hhs.gov/physicians/pfs/ default.asp. Accessed August 2002: 14. 16. deBaere T, Chapot R, Kuoch V, et al. Percutaneous gastrostomy with fluoroscopic guidance: single-center experience in 500 consecutive cancer patients. Radiology 1999; 210:651– 654. 17. Dewald CL, Hiette PO, Sewall LE, Fredenberg PG, Palestrant AM. Percutaneous gastrostomy and gastrojejunostomy with gastropexy: experience in
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