ORIGINAL ARTICLE
Increasing Access to Specialty Surgical Care Application of a New Resource Allocation Model to Bariatric Surgery Eric J. Leroux, MD, MBA,∗ † John M. Morton, MD, MPH, MHA,‡ and Homero Rivas, MD, MBA‡ Objectives: To calculate the public health impact and economic benefit of using ancillary health care professionals for routine postoperative care. Background: The need for specialty surgical care far exceeds its supply, particularly in weight loss surgery. Bariatric surgery is cost-effective and the only effective long-term weight loss strategy for morbidly obese patients. Without clinically appropriate task shifting, surgeons, hospitals, and untreated patients incur a high opportunity cost. Methods: Visit schedules, time per visit, and revenues were obtained from bariatric centers of excellence. Case-specific surgeon fees were derived from published Current Procedural Terminology data. The novel Microsoft Excel model was allowed to run until a steady state was evident (status quo). This model was compared with one in which the surgeon participates in follow-up visits beyond 3 months only if there is a complication (task shifting). Changes in operative capacity and national quality-adjusted life years (QALYs) were calculated. Results: In the status quo model, per capita surgical volume capacity equilibrates at 7 surgical procedures per week, with 27% of the surgeon’s time dedicated to routine long-term follow-up visits. Task shifting increases operative capacity by 38%, resulting in 143,000 to 882,000 QALYs gained annually. Per surgeon, task shifting achieves an annual increase of 95 to 588 QALYs, $5 million in facility revenue, 48 cases of cure of obstructive sleep apnea, 44 cases of remission of type 2 diabetes mellitus, and 35 cases of cure of hypertension. Conclusions: Optimal resource allocation through task shifting is economically appealing and can achieve dramatic public health benefit by increasing access to specialty surgery. Keywords: bariatric, cost-effective, opportunity cost, surgery, surgical access (Ann Surg 2014;260:274–278)
O
besity is a worldwide problem with global health repercussions and tremendous economic impact. It has been described as the first noninfectious epidemic and has become one of the most important subjects of concern for public health programs around the world.1,2 Although preventive measures must remain a top priority and mainstay of our response to obesity, it is estimated that 36% of Americans are obese and that 22 million are eligible for gastric bypass surgery.3,4 Eligibility for weight reduction surgery (bariatric surgery) has traditionally been restricted either to morbidly obese patients with a body mass index of 40 or more or to those with a body mass index of 35 or more who also have serious obesity-related comorbidities. Recently, the Food and Drug Administration expanded the indications
to a type of laparoscopic adjustable gastric banding as an appropriate intervention for patients with a body mass index of 30 or more.5 Of the available treatment options for obesity, only surgery is effective in long-term weight control.6 Similarly, substantial improvement in comorbidities is well documented and a reduction in the relative risk of death has been demonstrated.7–11 Metabolic surgery is also widely regarded as an effective treatment option for type 2 diabetes mellitus.12–16 Because bariatric surgery is a cost-effective treatment option for obesity and its comorbidities, access to this intervention is an important matter of public health.6,17 Eligibility of patients with class 1 obesity instantaneously doubles the population who might benefit from surgery, with no change in the available resources to provide this care.5,18 Although bariatric surgery dramatically improves weight loss results when compared with conservative nonsurgical methods (ie, diet, exercise, medication, hypnosis, acupuncture, etc), patients regain weight unless they adopt or maintain healthy lifestyles. Successful long-term weight loss and postoperative safety require long-term clinical monitoring and management. Currently, this follow-up care relies heavily on the bariatric surgeons themselves. As presently practiced, a single given patient will represent multiple pre- and postsurgical visits.19,20 This follow-up care results in a nonlinear increase in clinic schedule requirements and by a proportional margin incrementally reduces a surgeon’s available operative time. The learning and mastery of weight loss surgery require multiple years of training and steep learning curves.16,21–24 Presently, there are approximately 1500 experienced bariatric surgeons and most of them have mixed practices (general surgery, vascular surgery, etc).25 Every year in the United States, more than 220,000 bariatric surgical procedures are performed, but this volume represents less than 1% of the need for weight loss surgery.26 Opportunity cost (OC) is the cost of a choice as determined by the value of the next-best alternative that was not chosen. This concept, although central to economics, is frequently forgotten when considering the overall cost of health care, particularly among surgeons.27–31 Our model is a first attempt to describe the OC of bariatric surgeons serving as long-term care providers for postoperative patients. By patterning an alternative patient flow paradigm, we can compare different resource allocation options and their relative impacts on patient volumes and outcomes. In response to an ever-increasing population of postoperative patients, we investigate the public health impact of task-shifting routine long-term follow-up (LTFU) visits to obesity care professionals other than the surgeon.
METHODS From the ∗ Stanford University School of Medicine, Stanford, CA; †Stanford Graduate School of Business, Stanford, CA; and ‡Section of Minimally Invasive Surgery, Division of General Surgery, Stanford Department of Surgery, Stanford, CA. Disclosure: The authors declare no conflicts of interest and no other funding disclosures. Reprints: Eric J. Leroux, MD, MBA, Stanford University School of Medicine, 300 Pasteur Dr, Stanford, CA 94305. E-mail: [email protected]. C 2014 by Lippincott Williams & Wilkins Copyright ISSN: 0003-4932/14/26002-0274 DOI: 10.1097/SLA.0000000000000656
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Hospital charges were obtained from 9 bariatric centers of excellence in the United States. Case-specific professional fees for the primary surgeon were based on Current Procedural Terminology codes to represent a weighted average of rates from Medicare, Blue Cross and Blue Shields, and other insurance providers, each of whom represent approximately one third of payers for bariatric surgical procedures. Opportunity cost multipliers (OCMs) were then calculated by dividing estimated revenues by an estimated average surgical time and adjusted for revenues associated with clinic visits. Annals of Surgery r Volume 260, Number 2, August 2014
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Annals of Surgery r Volume 260, Number 2, August 2014
Resource Allocation and Opportunity Costs
Perioperative time allocation for the surgeon was modeled on the basis of a generic status quo in which the surgeon sees patients at each pre- and postoperative visit. For illustrative purposes, we focus the model on the most common and effective bariatric procedure, the Roux-en-Y gastric bypass (RYGB), which requires a follow-up visit schedule similar to other weight loss procedures. The generic status quo situation included 2 preoperative visits per procedure, the surgery itself, an allowance for unplanned complication visits, and scheduled routine follow-up visits occurring at 2 weeks, at 6 weeks, and at 3, 6, 9, 12, 18, 24, 36, 48, and 60 months after surgery. The model describes the allocation of a surgeon’s time and overall operative capacity with respect to patients receiving an RYGB. The model first simulates the current system to elucidate a “breakpoint” at which a surgeon who maintains a consistent surgical volume has clinical demands that exceed 50 hours per week. This is the point at which a new practice must reduce surgical volume, expand staffing, or adjust the allocation of human resources. In this scenario, the number of surgical procedures per week was fixed at 8 whereas associated demands on the surgeon’s time were dependent on surgical volume. Second, a steady state of the status quo model was determined. In this simulation, the number of surgical procedures performed per week was dependent on time allocated to other clinical duties while limiting a surgeon’s total available time to 50 hours per week. This status quo was then compared with a task-shifted resource allocation model in which routine LTFU visits are managed by a physician assistant or nurse. Assumptions of the model are as follows: (1) patient visits include 2 preoperative visits, the surgery itself, and a postoperative visit schedule as outlined earlier; (2) postoperative visit attendance is 90% in the first year, 70% for years 2 and 3, and 50% thereafter32,33 ; (3) time required for routine visits is as follows: first preoperative visit 15 minutes, second preoperative visit 25 minutes, procedure 180 minutes, follow-up within 90 days 30 minutes, LTFU visit 15 minutes; (4) visits for complications require additional surgeon time of 15 minutes and occur at a rate of 7.25% during first 90 days and then at a rate of 2.45% beyond 90 days,34 and any associated reoperation time adds to the 50-hour week limit rather than impacting patient volumes; and (5) the surgeon’s time is the rate-limiting factor in increasing surgical volume. In economic terms, the OC incurred by the surgeon or hospital in the status quo model was defined as the product of the respective OCM and change in operative capacity described by the taskshifting model. To quantify the public health impact of task shifting, the change in quality-adjusted life years (QALYs) and impact on
specific comorbidities were calculated using published incremental cost-effectiveness ratio values for RYGB surgery and national level health data on the need and supply of bariatric surgery.
RESULTS RYGB surgery had the largest surgeon-specific OCM related to professional fees at $12.88 to 20.65 per minute, across a range of operative times from 120 to 180 minutes. OCMs for a 70-minute laparoscopic adjustable gastric banding surgery and for a 90-minute sleeve gastrectomy were $14.00 per minute and $13.37 per minute, respectively. The annual hospital-specific OC of a surgeon seeing RYGB patients at LTFU visits is $5.3 to 8.1 million (Table 1). Breakpoint analysis shows that at a fixed rate of 8 surgical procedures per week, a bariatric surgeon will reach capacity after 2 to 4 years, depending on postoperative visit attendance. This necessitates a reduction in surgical volume unless other growth-sustaining practices are introduced. Steady-state analysis describes a logarithmic increase in time allocated to LTFU visits such that the hourly weekly allocation to these uncomplicated visits in years 2, 4, 6, and 8 is 7.8, 9.6, 11.3, and 13.0, respectively. Thus, the difference in surgical capacity between the status quo and the task-shifted model increases with time, in accordance with the logarithmically increasing OC of a surgeon seeing patients for LTFU visits such that after 1 year, task shifting results in a 12% increase in operative capacity, 20% at 2 years, 26% at 3 years, and reaches 38% after 9 years (Fig. 1). Consequently, the steady state shows that in the status quo model, 43% of a surgeon’s clinical time is spent operating and 27% is allocated to seeing patients at LTFU visits (Fig. 2). Task shifting the LTFU visits to other health care professionals generates a new steady state in which 60% of a surgeon’s time is spent operating, representing an average increase in operative capacity of 34%. The proportion of a surgeon’s time devoted to LTFU visits is 9% after 1 year, increases to 16% at 2 years, 19% at 4 years, and climbs to 27% by year 9 (Fig. 2). Consequently, the status quo model describes a progressive decline, in both absolute and relative terms, in time that is available for preoperative visits, procedures themselves, and postoperative visits within 90 days. For 1 full-time bariatric surgeon, this task-shifting proposal reduces annual clinic time devoted to LTFU visits by 651 hours, which enables an increase in operative time of 396 hours. These operative hours represent a single-surgeon annual OC of $304,831 and a hospital OC of $5,345,099 in unrealized potential revenue. Although the cost-effectiveness of RYGB is well established, particularly for obese patients with diabetes, the incremental
TABLE 1. OC of Weight Loss Surgeons Seeing Patients at LTFU Visits Time per case, min Surgeon-specific fees per case, $ Surgeon-specific fees per LTFU visit, $ Surgeon OCM, $/min Hospital-specific revenue per case, $ Hospital-specific revenue per LTFU visit, $ Hospital OCM, $/min RYGB OC per surgeon Year 1 Year 3 Year 5 Year 7 Year 9
RYGB
AGB
SG
180 2,798 40 12.88 42,438 150 225.76
70 1,167 40 14.00 29,125 150 406.07
90 1,443 40 13.37 36,444 150 394.94
Increase in Access
Surgeon OC, $/yr
Hospital OC, $/yr
13.02% 22.10% 26.48% 32.42% 38.25%
128,315 201,049 232,257 271,297 306,198
2,249,961 3,525,320 4,072,547 4,757,095 5,369,062
AGB indicates adjustable gastric band; SG, sleeve gastrectomy.
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Annals of Surgery r Volume 260, Number 2, August 2014
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cost-effectiveness ratio estimates vary widely, from being cost saving at −$5700 per QALY to being cost-effective at $22,000 per QALY35–38 (Table 2). Nationally, task shifting increases access to RYGB surgery by 84,153 patients, corresponding to an average of 56 cases per surgeon by year 9. On the basis of QALY estimates of weight loss,37,39 this represents an annual national increase in QALYs of 143,059 to 881,733, which represents a per surgeon increase of as many as 588 QALYs per year. Along with this increase in life years, based on rates of comorbidity resolution,7 each surgeon on average cures an additional 48 cases of obstructive sleep apnea, achieves remission for 44 cases of type 2 diabetes mellitus, and resolves 35 cases of hypertension, in addition to reducing overall mortality8,40 (Table 3).
DISCUSSION Obesity has become a global health challenge of escalating importance, with significant public health and economic implications. Increases in obesity prevalence are associated with approximately 12% of increased health care spending,2 and morbid obesity is associated with numerous serious comorbidities, many of which are shown to resolve or improve after RYGB. The cost-effectiveness of RYGB is well established, making surgery an important component of the public health response to obesity. This model describes a system design innovation of clinically appropriate resource allocation, simulates its impact on access to surgical care, and quantifies the resulting impact.
FIGURE 1. Comparison of operative capacity between surgeon-centered postoperative care (status quo) and taskshifting routine LTFU visits to ancillary health care professionals.
In the status quo model, time allocation to LTFU visits increases until a steady state is reached. During this stabilization process, operative capacity steadily declines, whereas in the task-shifted model, there is smoothening in how a surgeon’s time is provisioned. The OC described can be thought of as the potential benefit to public health that is not captured through adherence to the status quo scenario. Similarly, there are economic OCs based on our calculation of the surgeon OCM at $12.88 per minute and the hospital OCM of $225.76 per minute. Multiplying these values by the increase in surgical access describes the inefficiency of the status quo in financial terms. Instead, by using a surgeon’s limited time for clinical activities of the highest marginal benefit, and task shifting when clinically appropriate to do so, this potential efficiency can be captured, resulting in each surgeon adding almost 600 QALYs to his or her patient population per year. In addition to the increased access to care by the existing volume of bariatric surgeons, operative prioritization through task shifting may increase the available surgical workload for each surgeon. At academic medical centers, where the learning curve for proficiency in performing gastric bypass is estimated at 100 cases, the impact of adding 56 annual surgical procedures per surgeon could help enable graduating residents to achieve adeptness.41 Alternately, this increase in volume may enable an expansion of fellowship positions, further increasing the availability of specialists able to help meet the national and global needs for advanced and effective weight loss interventions. Increases in operative capacity described by our model are dependent on the assumption that surgeon capacity is the rate-limiting factor in overall surgical volume. This is theoretically true only when third-party coverage is 100%; however, the percentage of the need we are currently able to satisfy is so low that even if the thirdparty rejection rate of clinically eligible patients is 50%, the need will still far exceed supply. There are other constraints, such as the availability of operating rooms and ancillary health care professionals. However, the simplistic model describes the general condition at most surgical centers where the learning curve and hiring process for bariatric surgeons are far longer than for other care professionals. Other limitations of the model include omission of reoperations, and complete noninvolvement of the surgeon beyond 90 days, which is a simplification. These adjustments are not modeled because it is estimated that reoperations and unexpected visits beyond 90 days that are not officially complication visits are added to a surgeon’s week, over and above the 50-hour constraint of the model. Finally, although the need for bariatric surgery continues to grow, the factors underlying patient demand for weight loss surgery are poorly understood. Optimal allocation of human resources plays an important role in cost containment and increasing access to effective interventions.
FIGURE 2. Comparison of a surgeon’s clinical duties and associated allocation of his or her time between the status quo scenario and the task-shifted model. FUV indicates follow-up visits that are within 90 days of surgery; Pre-op, preoperative. 276 | www.annalsofsurgery.com
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Annals of Surgery r Volume 260, Number 2, August 2014
Resource Allocation and Opportunity Costs
TABLE 2. Costs or Savings to National Health System Patient Population US obese patients with T2DM Austrian obese patients with T2DM Italian obese patients with T2DM Spanish obese patients with T2DM US patients with a new diagnosis of T2DM with severe obesity US patients with an established diagnosis of T2DM with severe obesity RYGB patients Obese patients with a long-term risk of T2DM
ICER
Low Estimate (QALY Gain = 1.70)
High Estimate (QALY Gain = 10.48)
−4,769.38 −1,924.51 −1,657.18 3,543.12 7,473.27
($682,305,025) ($275,319,401) ($237,075,310) $506,876,906 $1,069,122,123
($4,205,317,897) ($1,696,903,234) ($1,461,189,654) $3,124,084,461 $6,589,425,896
9,310
$1,331,883,763
$8,208,930,641
−1,561.42 21,973
($223,375,934) $3,143,445,963
($1,376,754,939) $19,374,310,738
The ICER and QALY differences are based on different populations referenced and described in the first column of the table. ICER indicates incremental cost-effectiveness ratio; T2DM, type 2 diabetes mellitus.
TABLE 3. QALYs Gained and Comorbidities Resolved QALYs Attributable to Task Shifting Patient Population
QALY Gain
Nationally
Per Surgeon
10.48 2.21
881,733 185,977
588 124
1.70
143,059
95
Obese patients US patients with a new diagnosis T2DM with severe obesity US patients with an established diagnosis of T2DM with severe obesity
Comorbidity Resolution Attributable to Task Shifting OSA cases cured T2DM cases in remission HTN cases cured Reduction in death rate Reduction in mortality due to reduced comorbidities
Nationally 72,371 65,723 52,175 37,869 24,404
Per Surgeon 48 44 35 25 16
Cure or remission rates for OSA, T2DM, and HTN are set at 86%, 78%, and 62%, respectively, based on the citations given in the table. The QALY range is due to variation in cost-effectiveness data for RYGB surgery, based on citations given in the table. HTN indicates hypertension; OSA, obstructive sleep apnea.
Although not always salient on a day-to-day basis, the benefits of task-shifting routine postoperative care represent a fundamental consideration of any specialty surgical practice. There is no substitute for compassionate patient-centered care. Focusing human resources where they can deliver maximum public health benefit is compassionate. However, more work is needed to clarify the cost-effectiveness of bariatric interventions, as there is a wide range of results from different settings. In addition, assumptions in our model about which visits require a surgeon are estimates. For each practice, patient-specific circumstances are likely to inform such decisions, but further work in characterizing and predicting the clinical demands of each visit may help inform optimal patient flow. In general, a simultaneous consideration of the health and economic implications of resource allocation ought to help inform decisions about how best to reduce obesity-related morbidity and mortality. Allocating this additional capacity to the patient population with the largest potential benefit further serves a national and global health imperative.
CONCLUSIONS Patients undergoing bariatric surgery require long-term followup to attain successful outcomes. Modeling the clinical requirements of these patients demonstrates how innovative allocation of scarce C 2014 Lippincott Williams & Wilkins
human resources can considerably expand treatment capacity to meet a greater portion of the national need for weight loss surgery. RYGB surgery is shown as a test case for task shifting that has applications in every health system with resource constraints. Simple task shifting suggested by our model has the potential for surgeons to capture a $460 million OC, expand access to cost-effective and highly efficacious interventions to an additional 84,000 Americans annually, and generate a potential increase in QALYs of nearly 900,000. Efficient resource allocation in specialty surgery can lead to perioperative management processes capable of achieving substantial economic and public health benefit.
ACKNOWLEDGMENTS The authors are grateful for editing assistance provided by David L. M. Preston, MA. They also appreciate the valuable commentary Drew Hart, MBA, provided on opportunity cost multipliers.
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3. Flegal KM, Carroll MD, Kit BK, et al. Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999–2010. JAMA. 2012;307:491–497. 4. Martin M, Beekley A, Kjorstad R, et al. Socioeconomic disparities in eligibility and access to bariatric surgery: a national population-based analysis. Surg Obes Relat Dis. 2010;6:8–15. 5. Mitka M. FDA action allows more obese patients to qualify for a bariatric procedure. JAMA. 2011;305:1287–1288. 6. Picot J, Jones J, Colquitt JL, et al. The clinical effectiveness and costeffectiveness of bariatric (weight loss) surgery for obesity: a systematic review and economic evaluation. Health Technol Assess. 2009;13:1–190, 215–357, iii–iv. 7. Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: a systematic review and meta-analysis. JAMA. 2004;292:1724–1737. 8. Christou NV, Sampalis JS, Liberman M, et al. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Ann Surg. 2004;240:416–423; discussion 423–424. 9. Schernthaner G, Morton JM. Bariatric surgery in patients with morbid obesity and type 2 diabetes. Diabetes Care. 2008;31(suppl 2):S297–S302. 10. Wolfe BM, Morton JM. Weighing in on bariatric surgery: procedure use, readmission rates, and mortality. JAMA. 2005;294:1960–1963. 11. Livingston EH. Bariatric surgery in the new millennium. Arch Surg. 2007;142:919–922. 12. Schauer PR, Kashyap SR, Wolski K, et al. Bariatric surgery versus intensive medical therapy in obese patients with diabetes. N Engl J Med. 2012;366:1567– 1576. 13. Buchwald H, Estok R, Fahrbach K, et al. Weight and type 2 diabetes after bariatric surgery: systematic review and meta-analysis. Am J Med. 2009;122:248–256.e5. 14. Scopinaro N, Marinari GM, Camerini GB, et al. Specific effects of biliopancreatic diversion on the major components of metabolic syndrome: a long-term follow-up study. Diabetes Care. 2005;28:2406–2411. 15. Sjostrom L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med. 2004;351:2683–2693. 16. Schauer PR, Burguera B, Ikramuddin S, et al. Effect of laparoscopic Roux-en Y gastric bypass on type 2 diabetes mellitus. Ann Surg. 2003;238:467–484; discussion 84–85. 17. McEwen LN, Coelho RB, Baumann LM, et al. The cost, quality of life impact, and cost-utility of bariatric surgery in a managed care population. Obes Surg. 2010;20:919–928. 18. Livingston EH. Lowering the bariatric surgery minimum body mass index threshold. Arch Surg. 2008;143:708–710. 19. Gould JC, Beverstein G, Reinhardt S, et al. Impact of routine and long-term follow-up on weight loss after laparoscopic gastric bypass. Surg Obes Relat Dis. 2007;3:627–630; discussion 630. 20. Shen R, Dugay G, Rajaram K, et al. Impact of patient follow-up on weight loss after bariatric surgery. Obes Surg. 2004;14:514–519. 21. Schirmer BD, Schauer PR, Flum DR, et al. Bariatric surgery training: getting your ticket punched. J Gastrointest Surg. 2007;11:807–812.
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22. Oliak D, Owens M, Schmidt HJ. Impact of fellowship training on the learning curve for laparoscopic gastric bypass. Obes Surg. 2004;14:197–200. 23. Kothari SN, Boyd WC, Larson CA, et al. Training of a minimally invasive bariatric surgeon: are laparoscopic fellowships the answer? Obes Surg. 2005; 15:323–329. 24. Ali MR, Tichansky DS, Kothari SN, et al. Validation that a 1-year fellowship in minimally invasive and bariatric surgery can eliminate the learning curve for laparoscopic gastric bypass. Surg Endosc. 2010;24:138–144. 25. Buchwald H, Oien DM. Metabolic/bariatric surgery worldwide 2008. Obes Surg. 2009;19:1605–1611. 26. Prachand VN. The evolution of minimally invasive bariatric surgery. World J Surg. 2011;35:1464–1468. 27. Frederick S NN, Wang J, Dhar R, Nowlis S. Opportunity cost neglect. J Consumer Res. 2009;36:553–561. 28. Chatterjee A, Payette MJ, Demas CP, et al. Opportunity cost: a systematic application to surgery. Surgery. 2009;146:18–22. 29. McGregor M. Paying for technology. The cost of ignoring opportunity costs. Healthc Q. 2010;13:90–92. 30. Rivas H, Morton JM, Krummel TM. Cost consciousness and medical education. N Engl J Med. 2010;363:888–889; author reply 890–891. 31. Falvo T, Grove L, Stachura R, et al. The opportunity loss of boarding admitted patients in the emergency department. Acad Emerg Med. 2007;14:332–337. 32. DeNino WF, Osler T, Evans EG, et al. Travel distance as factor in follow-up visit compliance in postlaparoscopic adjustable gastric banding population. Surg Obes Relat Dis. 2010;6:597–600. 33. Lorentz PA, Swain JM, Gall MM, et al. Combined group and individual model for postbariatric surgery follow-up care. Surg Obes Relat Dis. 2012;8:220–224. 34. Chebli JE, Schindler R. The results of a surgical complication protection program (BLIS, Inc.) for private pay bariatric patients in the U.S.: 2006–2011. Obes Surg. 2012;22:1798–1801. 35. Anselmino M, Bammer T, Fernandez Cebrian JM, et al. Cost-effectiveness and budget impact of obesity surgery in patients with type 2 diabetes in three European countries. Obes Surg. 2009;19:1542–1549. 36. Ikramuddin S, Klingman D, Swan T, et al. Cost-effectiveness of Roux-en-Y gastric bypass in type 2 diabetes patients. Am J Manag Care. 2009;15:607–615. 37. Hoerger TJ, Zhang P, Segel JE, et al. Cost-effectiveness of bariatric surgery for severely obese adults with diabetes. Diabetes Care. 2010;33: 1933–1939. 38. CDC Diabetes Cost-effectiveness Group. Cost-effectiveness of intensive glycemic control, intensified hypertension control, and serum cholesterol level reduction for type 2 diabetes. JAMA. 2002;287:2542–2551. 39. Hernandez LV, Klyve D. Quality-adjusted life expectancy benefits of laparoscopic bariatric surgery: a United States perspective. Int J Technol Assess Health Care. 2010;26:280–287. 40. Pontiroli AE, Morabito A. Long-term prevention of mortality in morbid obesity through bariatric surgery. A systematic review and meta-analysis of trials performed with gastric banding and gastric bypass. Ann Surg. 2011;253:484– 487. 41. Schauer P, Ikramuddin S, Hamad G, et al. The learning curve for laparoscopic Roux-en-Y gastric bypass is 100 cases. Surg Endosc. 2003;17:212–215.
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Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Increasing Access to Specialty Surgical Care Application of a New Resource Allocation Model to Bariatric Surgery Eric J. Leroux, MD, MBA,∗ † John M. Morton, MD, MPH, MHA,‡ and Homero Rivas, MD, MBA‡ Objectives: To calculate the public health impact and economic benefit of using ancillary health care professionals for routine postoperative care. Background: The need for specialty surgical care far exceeds its supply, particularly in weight loss surgery. Bariatric surgery is cost-effective and the only effective long-term weight loss strategy for morbidly obese patients. Without clinically appropriate task shifting, surgeons, hospitals, and untreated patients incur a high opportunity cost. Methods: Visit schedules, time per visit, and revenues were obtained from bariatric centers of excellence. Case-specific surgeon fees were derived from published Current Procedural Terminology data. The novel Microsoft Excel model was allowed to run until a steady state was evident (status quo). This model was compared with one in which the surgeon participates in follow-up visits beyond 3 months only if there is a complication (task shifting). Changes in operative capacity and national quality-adjusted life years (QALYs) were calculated. Results: In the status quo model, per capita surgical volume capacity equilibrates at 7 surgical procedures per week, with 27% of the surgeon’s time dedicated to routine long-term follow-up visits. Task shifting increases operative capacity by 38%, resulting in 143,000 to 882,000 QALYs gained annually. Per surgeon, task shifting achieves an annual increase of 95 to 588 QALYs, $5 million in facility revenue, 48 cases of cure of obstructive sleep apnea, 44 cases of remission of type 2 diabetes mellitus, and 35 cases of cure of hypertension. Conclusions: Optimal resource allocation through task shifting is economically appealing and can achieve dramatic public health benefit by increasing access to specialty surgery. Keywords: bariatric, cost-effective, opportunity cost, surgery, surgical access (Ann Surg 2014;260:274–278)
O
besity is a worldwide problem with global health repercussions and tremendous economic impact. It has been described as the first noninfectious epidemic and has become one of the most important subjects of concern for public health programs around the world.1,2 Although preventive measures must remain a top priority and mainstay of our response to obesity, it is estimated that 36% of Americans are obese and that 22 million are eligible for gastric bypass surgery.3,4 Eligibility for weight reduction surgery (bariatric surgery) has traditionally been restricted either to morbidly obese patients with a body mass index of 40 or more or to those with a body mass index of 35 or more who also have serious obesity-related comorbidities. Recently, the Food and Drug Administration expanded the indications
to a type of laparoscopic adjustable gastric banding as an appropriate intervention for patients with a body mass index of 30 or more.5 Of the available treatment options for obesity, only surgery is effective in long-term weight control.6 Similarly, substantial improvement in comorbidities is well documented and a reduction in the relative risk of death has been demonstrated.7–11 Metabolic surgery is also widely regarded as an effective treatment option for type 2 diabetes mellitus.12–16 Because bariatric surgery is a cost-effective treatment option for obesity and its comorbidities, access to this intervention is an important matter of public health.6,17 Eligibility of patients with class 1 obesity instantaneously doubles the population who might benefit from surgery, with no change in the available resources to provide this care.5,18 Although bariatric surgery dramatically improves weight loss results when compared with conservative nonsurgical methods (ie, diet, exercise, medication, hypnosis, acupuncture, etc), patients regain weight unless they adopt or maintain healthy lifestyles. Successful long-term weight loss and postoperative safety require long-term clinical monitoring and management. Currently, this follow-up care relies heavily on the bariatric surgeons themselves. As presently practiced, a single given patient will represent multiple pre- and postsurgical visits.19,20 This follow-up care results in a nonlinear increase in clinic schedule requirements and by a proportional margin incrementally reduces a surgeon’s available operative time. The learning and mastery of weight loss surgery require multiple years of training and steep learning curves.16,21–24 Presently, there are approximately 1500 experienced bariatric surgeons and most of them have mixed practices (general surgery, vascular surgery, etc).25 Every year in the United States, more than 220,000 bariatric surgical procedures are performed, but this volume represents less than 1% of the need for weight loss surgery.26 Opportunity cost (OC) is the cost of a choice as determined by the value of the next-best alternative that was not chosen. This concept, although central to economics, is frequently forgotten when considering the overall cost of health care, particularly among surgeons.27–31 Our model is a first attempt to describe the OC of bariatric surgeons serving as long-term care providers for postoperative patients. By patterning an alternative patient flow paradigm, we can compare different resource allocation options and their relative impacts on patient volumes and outcomes. In response to an ever-increasing population of postoperative patients, we investigate the public health impact of task-shifting routine long-term follow-up (LTFU) visits to obesity care professionals other than the surgeon.
METHODS From the ∗ Stanford University School of Medicine, Stanford, CA; †Stanford Graduate School of Business, Stanford, CA; and ‡Section of Minimally Invasive Surgery, Division of General Surgery, Stanford Department of Surgery, Stanford, CA. Disclosure: The authors declare no conflicts of interest and no other funding disclosures. Reprints: Eric J. Leroux, MD, MBA, Stanford University School of Medicine, 300 Pasteur Dr, Stanford, CA 94305. E-mail: [email protected]. C 2014 by Lippincott Williams & Wilkins Copyright ISSN: 0003-4932/14/26002-0274 DOI: 10.1097/SLA.0000000000000656
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Hospital charges were obtained from 9 bariatric centers of excellence in the United States. Case-specific professional fees for the primary surgeon were based on Current Procedural Terminology codes to represent a weighted average of rates from Medicare, Blue Cross and Blue Shields, and other insurance providers, each of whom represent approximately one third of payers for bariatric surgical procedures. Opportunity cost multipliers (OCMs) were then calculated by dividing estimated revenues by an estimated average surgical time and adjusted for revenues associated with clinic visits. Annals of Surgery r Volume 260, Number 2, August 2014
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Annals of Surgery r Volume 260, Number 2, August 2014
Resource Allocation and Opportunity Costs
Perioperative time allocation for the surgeon was modeled on the basis of a generic status quo in which the surgeon sees patients at each pre- and postoperative visit. For illustrative purposes, we focus the model on the most common and effective bariatric procedure, the Roux-en-Y gastric bypass (RYGB), which requires a follow-up visit schedule similar to other weight loss procedures. The generic status quo situation included 2 preoperative visits per procedure, the surgery itself, an allowance for unplanned complication visits, and scheduled routine follow-up visits occurring at 2 weeks, at 6 weeks, and at 3, 6, 9, 12, 18, 24, 36, 48, and 60 months after surgery. The model describes the allocation of a surgeon’s time and overall operative capacity with respect to patients receiving an RYGB. The model first simulates the current system to elucidate a “breakpoint” at which a surgeon who maintains a consistent surgical volume has clinical demands that exceed 50 hours per week. This is the point at which a new practice must reduce surgical volume, expand staffing, or adjust the allocation of human resources. In this scenario, the number of surgical procedures per week was fixed at 8 whereas associated demands on the surgeon’s time were dependent on surgical volume. Second, a steady state of the status quo model was determined. In this simulation, the number of surgical procedures performed per week was dependent on time allocated to other clinical duties while limiting a surgeon’s total available time to 50 hours per week. This status quo was then compared with a task-shifted resource allocation model in which routine LTFU visits are managed by a physician assistant or nurse. Assumptions of the model are as follows: (1) patient visits include 2 preoperative visits, the surgery itself, and a postoperative visit schedule as outlined earlier; (2) postoperative visit attendance is 90% in the first year, 70% for years 2 and 3, and 50% thereafter32,33 ; (3) time required for routine visits is as follows: first preoperative visit 15 minutes, second preoperative visit 25 minutes, procedure 180 minutes, follow-up within 90 days 30 minutes, LTFU visit 15 minutes; (4) visits for complications require additional surgeon time of 15 minutes and occur at a rate of 7.25% during first 90 days and then at a rate of 2.45% beyond 90 days,34 and any associated reoperation time adds to the 50-hour week limit rather than impacting patient volumes; and (5) the surgeon’s time is the rate-limiting factor in increasing surgical volume. In economic terms, the OC incurred by the surgeon or hospital in the status quo model was defined as the product of the respective OCM and change in operative capacity described by the taskshifting model. To quantify the public health impact of task shifting, the change in quality-adjusted life years (QALYs) and impact on
specific comorbidities were calculated using published incremental cost-effectiveness ratio values for RYGB surgery and national level health data on the need and supply of bariatric surgery.
RESULTS RYGB surgery had the largest surgeon-specific OCM related to professional fees at $12.88 to 20.65 per minute, across a range of operative times from 120 to 180 minutes. OCMs for a 70-minute laparoscopic adjustable gastric banding surgery and for a 90-minute sleeve gastrectomy were $14.00 per minute and $13.37 per minute, respectively. The annual hospital-specific OC of a surgeon seeing RYGB patients at LTFU visits is $5.3 to 8.1 million (Table 1). Breakpoint analysis shows that at a fixed rate of 8 surgical procedures per week, a bariatric surgeon will reach capacity after 2 to 4 years, depending on postoperative visit attendance. This necessitates a reduction in surgical volume unless other growth-sustaining practices are introduced. Steady-state analysis describes a logarithmic increase in time allocated to LTFU visits such that the hourly weekly allocation to these uncomplicated visits in years 2, 4, 6, and 8 is 7.8, 9.6, 11.3, and 13.0, respectively. Thus, the difference in surgical capacity between the status quo and the task-shifted model increases with time, in accordance with the logarithmically increasing OC of a surgeon seeing patients for LTFU visits such that after 1 year, task shifting results in a 12% increase in operative capacity, 20% at 2 years, 26% at 3 years, and reaches 38% after 9 years (Fig. 1). Consequently, the steady state shows that in the status quo model, 43% of a surgeon’s clinical time is spent operating and 27% is allocated to seeing patients at LTFU visits (Fig. 2). Task shifting the LTFU visits to other health care professionals generates a new steady state in which 60% of a surgeon’s time is spent operating, representing an average increase in operative capacity of 34%. The proportion of a surgeon’s time devoted to LTFU visits is 9% after 1 year, increases to 16% at 2 years, 19% at 4 years, and climbs to 27% by year 9 (Fig. 2). Consequently, the status quo model describes a progressive decline, in both absolute and relative terms, in time that is available for preoperative visits, procedures themselves, and postoperative visits within 90 days. For 1 full-time bariatric surgeon, this task-shifting proposal reduces annual clinic time devoted to LTFU visits by 651 hours, which enables an increase in operative time of 396 hours. These operative hours represent a single-surgeon annual OC of $304,831 and a hospital OC of $5,345,099 in unrealized potential revenue. Although the cost-effectiveness of RYGB is well established, particularly for obese patients with diabetes, the incremental
TABLE 1. OC of Weight Loss Surgeons Seeing Patients at LTFU Visits Time per case, min Surgeon-specific fees per case, $ Surgeon-specific fees per LTFU visit, $ Surgeon OCM, $/min Hospital-specific revenue per case, $ Hospital-specific revenue per LTFU visit, $ Hospital OCM, $/min RYGB OC per surgeon Year 1 Year 3 Year 5 Year 7 Year 9
RYGB
AGB
SG
180 2,798 40 12.88 42,438 150 225.76
70 1,167 40 14.00 29,125 150 406.07
90 1,443 40 13.37 36,444 150 394.94
Increase in Access
Surgeon OC, $/yr
Hospital OC, $/yr
13.02% 22.10% 26.48% 32.42% 38.25%
128,315 201,049 232,257 271,297 306,198
2,249,961 3,525,320 4,072,547 4,757,095 5,369,062
AGB indicates adjustable gastric band; SG, sleeve gastrectomy.
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Annals of Surgery r Volume 260, Number 2, August 2014
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cost-effectiveness ratio estimates vary widely, from being cost saving at −$5700 per QALY to being cost-effective at $22,000 per QALY35–38 (Table 2). Nationally, task shifting increases access to RYGB surgery by 84,153 patients, corresponding to an average of 56 cases per surgeon by year 9. On the basis of QALY estimates of weight loss,37,39 this represents an annual national increase in QALYs of 143,059 to 881,733, which represents a per surgeon increase of as many as 588 QALYs per year. Along with this increase in life years, based on rates of comorbidity resolution,7 each surgeon on average cures an additional 48 cases of obstructive sleep apnea, achieves remission for 44 cases of type 2 diabetes mellitus, and resolves 35 cases of hypertension, in addition to reducing overall mortality8,40 (Table 3).
DISCUSSION Obesity has become a global health challenge of escalating importance, with significant public health and economic implications. Increases in obesity prevalence are associated with approximately 12% of increased health care spending,2 and morbid obesity is associated with numerous serious comorbidities, many of which are shown to resolve or improve after RYGB. The cost-effectiveness of RYGB is well established, making surgery an important component of the public health response to obesity. This model describes a system design innovation of clinically appropriate resource allocation, simulates its impact on access to surgical care, and quantifies the resulting impact.
FIGURE 1. Comparison of operative capacity between surgeon-centered postoperative care (status quo) and taskshifting routine LTFU visits to ancillary health care professionals.
In the status quo model, time allocation to LTFU visits increases until a steady state is reached. During this stabilization process, operative capacity steadily declines, whereas in the task-shifted model, there is smoothening in how a surgeon’s time is provisioned. The OC described can be thought of as the potential benefit to public health that is not captured through adherence to the status quo scenario. Similarly, there are economic OCs based on our calculation of the surgeon OCM at $12.88 per minute and the hospital OCM of $225.76 per minute. Multiplying these values by the increase in surgical access describes the inefficiency of the status quo in financial terms. Instead, by using a surgeon’s limited time for clinical activities of the highest marginal benefit, and task shifting when clinically appropriate to do so, this potential efficiency can be captured, resulting in each surgeon adding almost 600 QALYs to his or her patient population per year. In addition to the increased access to care by the existing volume of bariatric surgeons, operative prioritization through task shifting may increase the available surgical workload for each surgeon. At academic medical centers, where the learning curve for proficiency in performing gastric bypass is estimated at 100 cases, the impact of adding 56 annual surgical procedures per surgeon could help enable graduating residents to achieve adeptness.41 Alternately, this increase in volume may enable an expansion of fellowship positions, further increasing the availability of specialists able to help meet the national and global needs for advanced and effective weight loss interventions. Increases in operative capacity described by our model are dependent on the assumption that surgeon capacity is the rate-limiting factor in overall surgical volume. This is theoretically true only when third-party coverage is 100%; however, the percentage of the need we are currently able to satisfy is so low that even if the thirdparty rejection rate of clinically eligible patients is 50%, the need will still far exceed supply. There are other constraints, such as the availability of operating rooms and ancillary health care professionals. However, the simplistic model describes the general condition at most surgical centers where the learning curve and hiring process for bariatric surgeons are far longer than for other care professionals. Other limitations of the model include omission of reoperations, and complete noninvolvement of the surgeon beyond 90 days, which is a simplification. These adjustments are not modeled because it is estimated that reoperations and unexpected visits beyond 90 days that are not officially complication visits are added to a surgeon’s week, over and above the 50-hour constraint of the model. Finally, although the need for bariatric surgery continues to grow, the factors underlying patient demand for weight loss surgery are poorly understood. Optimal allocation of human resources plays an important role in cost containment and increasing access to effective interventions.
FIGURE 2. Comparison of a surgeon’s clinical duties and associated allocation of his or her time between the status quo scenario and the task-shifted model. FUV indicates follow-up visits that are within 90 days of surgery; Pre-op, preoperative. 276 | www.annalsofsurgery.com
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Annals of Surgery r Volume 260, Number 2, August 2014
Resource Allocation and Opportunity Costs
TABLE 2. Costs or Savings to National Health System Patient Population US obese patients with T2DM Austrian obese patients with T2DM Italian obese patients with T2DM Spanish obese patients with T2DM US patients with a new diagnosis of T2DM with severe obesity US patients with an established diagnosis of T2DM with severe obesity RYGB patients Obese patients with a long-term risk of T2DM
ICER
Low Estimate (QALY Gain = 1.70)
High Estimate (QALY Gain = 10.48)
−4,769.38 −1,924.51 −1,657.18 3,543.12 7,473.27
($682,305,025) ($275,319,401) ($237,075,310) $506,876,906 $1,069,122,123
($4,205,317,897) ($1,696,903,234) ($1,461,189,654) $3,124,084,461 $6,589,425,896
9,310
$1,331,883,763
$8,208,930,641
−1,561.42 21,973
($223,375,934) $3,143,445,963
($1,376,754,939) $19,374,310,738
The ICER and QALY differences are based on different populations referenced and described in the first column of the table. ICER indicates incremental cost-effectiveness ratio; T2DM, type 2 diabetes mellitus.
TABLE 3. QALYs Gained and Comorbidities Resolved QALYs Attributable to Task Shifting Patient Population
QALY Gain
Nationally
Per Surgeon
10.48 2.21
881,733 185,977
588 124
1.70
143,059
95
Obese patients US patients with a new diagnosis T2DM with severe obesity US patients with an established diagnosis of T2DM with severe obesity
Comorbidity Resolution Attributable to Task Shifting OSA cases cured T2DM cases in remission HTN cases cured Reduction in death rate Reduction in mortality due to reduced comorbidities
Nationally 72,371 65,723 52,175 37,869 24,404
Per Surgeon 48 44 35 25 16
Cure or remission rates for OSA, T2DM, and HTN are set at 86%, 78%, and 62%, respectively, based on the citations given in the table. The QALY range is due to variation in cost-effectiveness data for RYGB surgery, based on citations given in the table. HTN indicates hypertension; OSA, obstructive sleep apnea.
Although not always salient on a day-to-day basis, the benefits of task-shifting routine postoperative care represent a fundamental consideration of any specialty surgical practice. There is no substitute for compassionate patient-centered care. Focusing human resources where they can deliver maximum public health benefit is compassionate. However, more work is needed to clarify the cost-effectiveness of bariatric interventions, as there is a wide range of results from different settings. In addition, assumptions in our model about which visits require a surgeon are estimates. For each practice, patient-specific circumstances are likely to inform such decisions, but further work in characterizing and predicting the clinical demands of each visit may help inform optimal patient flow. In general, a simultaneous consideration of the health and economic implications of resource allocation ought to help inform decisions about how best to reduce obesity-related morbidity and mortality. Allocating this additional capacity to the patient population with the largest potential benefit further serves a national and global health imperative.
CONCLUSIONS Patients undergoing bariatric surgery require long-term followup to attain successful outcomes. Modeling the clinical requirements of these patients demonstrates how innovative allocation of scarce C 2014 Lippincott Williams & Wilkins
human resources can considerably expand treatment capacity to meet a greater portion of the national need for weight loss surgery. RYGB surgery is shown as a test case for task shifting that has applications in every health system with resource constraints. Simple task shifting suggested by our model has the potential for surgeons to capture a $460 million OC, expand access to cost-effective and highly efficacious interventions to an additional 84,000 Americans annually, and generate a potential increase in QALYs of nearly 900,000. Efficient resource allocation in specialty surgery can lead to perioperative management processes capable of achieving substantial economic and public health benefit.
ACKNOWLEDGMENTS The authors are grateful for editing assistance provided by David L. M. Preston, MA. They also appreciate the valuable commentary Drew Hart, MBA, provided on opportunity cost multipliers.
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