Cost implications of different surgical management strategies for primary hyperparathyroidism

Cost implications of different surgical management strategies for primary hyperparathyroidism Julie Ann Sosa, MD, Neil R. Powe, MD, MPH, MBA, Michael A. Levine, MD, Helen M. Bowman, MS, Martha A. Zeiger, MD, and Robert Udelsman, MD, Baltimore, Md

Background. Controversy exists about optimal management of patients with primary hyperparathyroidism. To date, no studies have explored the cost implications of variation in practice. Methods. Results from a national survey of endocrine surgeons were combined with results from a survey of endocrinologists and financial data from Medicare. Patterns of use of resources were identified, annual costs for the surgical management of primary hyperparathyroidism in the United States were calculated, and the financial impact of variation in practice was estimated. Results. Survey respondents (n = 109) were experienced endocrine surgeons, performing an average of 33 parathyroidectomies annually. Seventy-five percent of patients undergo localization before initial exploration for primary hyperparathyroidism. In order of preference, these studies were sestamibi (43%), ultrasonography (28%), and sestamibi with single-photon emission computed tomography (26%). Although there is variation in preoperative and postoperative practice, in-hospital costs have the greatest influence on total cost. An estimated $282 million is spent annually in the United States on operations for primary hyperparathyroidism. National health expenditures could range by more than $70 million, depending on whether management strategies involving low or high use of resources are employed. Conclusions. Substantial variation among endocrine surgeons in the management of primary hyperparathyroidism has important cost implications. Implementation of evidence-based guidelines to optimize clinical and economic performance should be considered. (Surgery 1998;124:1028-36.) From the Departments of Surgery, Medicine, Pathology, and Oncology and the Robert Wood Johnson Clinical Scholars Program, Johns Hopkins University School of Medicine, Departments of Epidemiology and Health Policy and Management, Johns Hopkins University School of Hygiene and Public Health, and Johns Hopkins Hospital, Baltimore, Md

UNTIL THE INTRODUCTION OF ROUTINE serum calcium screening in the 1970s, primary hyperparathyroidism was believed to be an uncommon metabolic disorder. Patients often sought treatment late, with advanced skeletal disease or nephrolithiasis, and typically were referred for surgical treatment.1 The development of multichannel autoanalyzers led to a dramatic change in the epidemiology and clinical profile of the disease. Patients are now diagnosed earlier, and the phenomenon of “asymptomatic” or “minimally symptomatic” primary hyperparathyroidism is a common mode of presentation.2-5 There is controversy about the optimal management of primary hyperparathyroidism.6-8 The principal debate is about whether asymptomatic priPresented at the 19th Annual Meeting of the American Association of Endocrine Surgeons, Orlando, Fla, Apr 26-28, 1998. Reprint requests: Robert Udelsman, MD, Division of Endocrine and Oncologic Surgery, Blalock 688, Johns Hopkins Hospital, 600 N Wolfe St, Baltimore, MD 21287. Copyright © 1998 by Mosby, Inc. 0039-6060/98/$5.00 + 0

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mary hyperparathyroidism should be managed with early operation or whether surveillance or medical therapy can be employed safely until the development of clinical sequelae. Even among surgeons, there appears to be lack of consensus about appropriate thresholds for operation and optimal preoperative localization strategies.9 In part, this is the result of a paucity of long-term data about potential adverse effects of asymptomatic primary hyperparathyroidism. Global issues pertaining to the management of primary hyperparathyroidism were last addressed in a comprehensive manner in a 1991 National Institutes of Health (NIH) Consensus Development Conference statement.10 Variation in practice patterns has important implications for health care costs and quality of care, especially given that primary hyperparathyroidism is the third most common endocrine disorder, after diabetes mellitus and hyperthyroidism. The potential economic impact of variation in management strategies was last addressed in 1980, when a break-even analysis suggested that the cost of early operation for primary hyperparathy-

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Fig 1. Format of cost-identification analysis for surgical management of primary hyperparathyroidism. Study began with literature review, followed by 2 surveys of national practice patterns of endocrine surgeons and endocrinologists and analysis of financial data from Maryland state discharge abstract registry and Medicare reimbursement fee schedule. Expert opinion was used to ensure reasonable estimates. RBRVS, Resource Based Relative Value Scale.

roidism would be exceeded by the cost of 5.5 years of medical follow-up.3 The economic impact of variation in current medical and surgical practice patterns is likely to be more substantial today, given that the cost of surveillance is greater and the number of patients diagnosed with primary hyperparathyroidism is increasing as a result of routine automated determinations of serum calcium levels. The incidence of primary hyperparathyroidism is also likely to increase in the United States as the population ages, because primary hyperparathyroidism is more common in the elderly.11 In this study we measured variation among endocrine surgeons in terms of the management of patients with asymptomatic or minimally symptomatic primary hyperparathyroidism who are referred for operation. We then estimated the implications of this variation in practice patterns for health care costs in the United States. METHODS Study design. Cost-identification analysis used information about prevailing practice patterns and associated costs involved in the surgical management of primary hyperparathyroidism (Fig 1). Analysis of practice patterns was based on primary data collected from national surveys of endocrine surgeons and endocrinologists with expertise in bone and mineral metabolism and on a review of the literature. Surgical charge data were obtained from the Maryland Health Services Cost Review Commission, and costs of laboratory tests, studies, and professional fees were obtained from Medicare. Survey development. Information about variation in the surgical management of primary hyper-

parathyroidism was obtained from a national, crosssectional survey of all North American members of the American Association of Endocrine Surgeons (AAES). Surveys were distributed to AAES members between May and July 1997. Information about variation in the medical management of primary hyperparathyroidism was obtained from a national sample of members of The Endocrine Society and the American Society for Bone and Mineral Research between December 1996 and January 1997. Both surveys inquired about physician demographics and training characteristics, clinical presentation of patients with primary hyperparathyroidism, use of resources (as measured by the use of preoperative localization studies, laboratory tests, office visits, and consultations), thresholds for surgery, and the health care environment (eg, degree of penetration of managed care). The surgical survey also collected information about operative strategies, length of hospital stay, type of anesthetic employed, and clinical outcomes (Table I), whereas the medical survey inquired about endocrinologists’ management and surveillance strategies, as well as thresholds for referral for operation. The study protocol was approved by the Joint Committee on Clinical Investigation at the Johns Hopkins Hospital. All responses were confidential, and unique numeric identifiers used to track respondents were eliminated before analysis. These primary data were supplemented with a MEDLINE search of articles published between 1966 and 1997 about primary hyperparathyroidism; 700 publications about operation for primary hyperparathyroidism and 103 articles about localization before operation were reviewed. Finally, 4 endocrine surgeons and endocrinologists

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Table I. Summary of contents in endocrine surgeons’ survey Patient Demographics Clinical presentation Surgeon Demographics Experience Practice Thresholds for surgery Outcomes Resource use Health care environment

Age, sex Symptoms, signs, previous medical therapy, underlying disease Age, sex, geographic location Training, program, caseload in training, advanced endocrine training Annual caseload, degree of specialization, clinical-administrativeresearch-teaching responsibilities Degree of abnormality of laboratory test results and symptoms Postoperative eucalcemia, complications, in-hospital deaths Localization studies, length of stay, anesthetic, laboratory tests, endocrinology consults Managed care penetration, type of practice

offered expert opinion to ensure that clinically relevant assumptions were used. Financial data. A cross-sectional analysis of length of stay and hospital charges for parathyroidectomy was conducted with discharge data from 53 nonfederal acute-care hospitals in Maryland. These publicly available data were used to identify all 1199 patients who underwent either a subtotal parathyroidectomy (International Classification of Diseases, 9th revision, procedure code 06.89) or a complete parathyroidectomy with or without reimplantation of parathyroid tissue (International Classification of Diseases, 9th revison, code 06.81, with or without 06.95) between January 1991 and June 1996. Hospital charges were adjusted for inflation based on the appropriate annual input of price indexes from the Health Care Financing Administration, and data are presented in constant 1996 dollars. 12 Hospital charges were skewed to the right, so a natural log transformation was performed. Results were converted to costs with hospital-specific, Medicare-based cost/charge ratios.13 The costs of localization studies, laboratory tests, and physicians’ professional fees for office visits and in-patient consultations and services provided by surgeons, anesthesiologists, endocrinologists, and pathologists were obtained from the Medicare fee schedule for Baltimore that is based on the 1996 Resource-Based Relative Value Scale.14 The time-dependent components of the professional fees for anesthesiology were calculated based on billing by the Department of Anesthesiology and Critical Care Medicine for 89 parathyroidectomies performed in 1997 at the Johns Hopkins Hospital. Estimates of national costs. The patterns of use of resources described by survey respondents were then combined with estimates of the incidence and prevalence of primary hyperparathyroidism from

the epidemiology literature and US population projections (Table II).15 These were supplemented when necessary with estimates obtained from the clinical literature.16,17 All these factors were applied to our financial data to generate projections of the cost of different surgical management strategies for primary hyperparathyroidism in the United States. Sensitivity analyses were performed to test the relative effects of different assumptions made in the cost-identification analysis. For example, surgeons were divided into low-, medium-, and highresource-use tiers based on the length of stay they reported for their patients, as well as on how intensely they used preoperative localization studies, perioperative laboratory tests and endocrinology consultations, and postoperative surveillance. Definitions of these cut points were dependent on the distribution of values for each factor. Statistical analysis. Data were entered into spreadsheets with Microsoft Excel Release 7.0 (Microsoft Corp, Redmond, Wash), and they were analyzed with STATA 5.0 (College Station, Tex). RESULTS Characteristics of respondents. Of the AAES members who received surveys, 147 (77.4%) responded (Table III). Thirty-eight surveys were incomplete, and these were not considered in the primary analysis (full-completion rate, 57.4%). Briefly, respondents were highly experienced, with an average of more than 20 years in practice; highly specialized, with an average of more than 40% of their practice in parathyroid and endocrine surgery; and clinically active, with an average of two thirds of their time spent in patient care (Table IV). Nearly half were in practices with more than 30% penetration by managed care. Characteristics of patients with primary hyperparathyroidism. According to endocrinologists, 61% of all patients with primary hyperparathy-

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Table II. Evidence table with selected probabilities used for projection of national estimates Components of surgical management model for primary hyperparathyroidism

Base care estimate

Epidemiology Incidence of primary hyperparathyroidism* 8/100,000 US population 262.8 million % of patients with primary hyperparathyroidism who are Symptom free 61 Have minimal symptoms 27 Have frank symptoms 12 % of patients referred for operation who are Symptom free 42 Have minimal symptoms 73 Have frank symptoms 98 % of referrals who undergo exploration and are Symptom free 82 Have minimal symptoms 95 Have frank symptoms 100 Clinical outcomes, primary operation % Success (eucalcemia 6 mo after operation) 95 % Failures referred to endocrine surgeons for reoperation† 48 Clinical outcome, reoperation % Success (eucalcemia 6 mo after operation) 83 *Estimates are

8/100,000,5

27/100,000,2

27.7/100,000,3

and

Alternative estimate

Source (reference)

27/100,000

2-5

9 9 9 AAES survey AAES survey AAES survey AAES survey AAES survey AAES survey AAES survey 16, 17 AAES survey

28/100,000.4

†Combined clinical series from Salti et al16 (308 patients) and Rudberg et al17 (441 patients) revealed that 4 of 7 and 15 of 33 (19/40; 47.5%) surgical failures were taken for reoperation.

Table III. Summary of survey responses Population

No.

AAES total membership, 1997 Excluded Corresponding members overseas Retired members Nonoperative (laboratory medicine, pathology) Eligible AAES members Complete and partial responses Complete responses*

231 24 10 7 190 147 109

Eligible members (%)

77.4 57.4

*Analysis was performed on complete responses only.

roidism are symptom free, and they refer 42% of symptom-free patients to surgeons. Surgeons reported that they operate on 82% of their symptom-free referrals. Therefore, 34% of all symptom-free patients with primary hyperparathyroidism undergo operation; the balance are followed up with surveillance or medical therapy. Endocrinologists generated the majority of referrals to endocrine surgeons (62.4%), and most of the patients they referred for operation had been followed up with laboratory surveillance and no medical therapy (91.2% of men and 69.8% of women). Adenomas were the most common cause of primary hyperparathyroidism (81.2% at primary operation; 70.3% at reoperation),

but multigland hyperplasia was found in 26.2% of patients undergoing reoperation. Preoperative use of localization studies. Nearly half (49.7%) of patients with primary hyperparathyroidism are referred to endocrine surgeons for exploration with preoperative localization studies that were ordered by their referring physicians. If a localization study has not been obtained, 41% of surgeons would routinely obtain one, and another 11.4% would selectively order one (Table V). Therefore, in contrast to the recommendation by the NIH that localization is not indicated before initial exploration, 75% of patients with primary hyperparathyroidism undergo at least 1 localiza-

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Table IV. Characteristics of respondents to endocrine surgeons’ survey (n = 109) Characteristic

Range

Sex (% male) % completing advanced endocrine training Years in practice (mean) No. parathyroidectomies performed last year (mean) % current practice in* Parathyroid surgery Other endocrine surgery Other general surgery % current parathyroid practice performing* Primary parathyroid operations Parathyroid reoperations % practice spent in following activities* Clinical Research Administrative, teaching % managed care penetration* <10% 10%-30% 30%-50% >50%

90.4 26.5 21 33

3-38 1-130

14.7 27.4 58.4

0-95 2.5-80 0-96

87.1 12.3

10-100 0-90

66.2 14.1 19.4

20-100 0-70 0-80

12.2 40.8 28.6 18.4

*Might not add to 100% because of rounding.

Table V. Cost and use of localization studies before parathyroidectomy for primary hyperparathyroidism % of physicians who use localization before Primary operation Localization study

Cost ($)*

CT with contrast MRI Sestamibi Sestamibi with SPECT Technetium thallium Ultrasonography Venous sampling

270.72 484.04 154.10 287.88 100.37 79.10 476.81

Referring physicians 8 6.8 34.3 15.9 8.2 26 0.7

Reoperation

Surgeons 3.4 0 43.1 25.9 0 27.6 0

Surgeons 8.4 3.1 34.3 36.1 7.2 8.4 2.4

CT, Computed tomography; MRI, magnetic resonance imaging; SPECT, single-photon emission computed tomography. *Based on participating physician reimbursement for Medicare and includes cost of tests and associated professional fees.

tion study. It is notable that there was no association between intensity of use of localization studies and rates of cure, postoperative complications, inhospital mortality, or length of stay. Sestamibi was the study obtained most frequently by endocrine surgeons, followed by ultrasonography and sestamibi with single-photon emission computed tomography. Among endocrinologists, the trends were the same, although there was more variation in their first-line imaging modalities. Surgeons most often obtained a localization study to decide on their surgical approach or incision (41.7%) or to decide on the extent of exploration (37.9%). Before reoperation, 100% of respondents reported obtaining at least 1 localization study. Sestamibi

with single-photon emission computed tomography and sestamibi were the studies of choice. Surgeons reported using these studies most often to decide on the extent of their exploration (40.7%) or to determine surgical approach or incision (37.9%). In-hospital length of stay and postoperative surveillance. On average, a general anesthetic was used in 97.1% of parathyroid operations; regional (cervical block) and local anesthetics were used in 1.5% and 1.4% of cases, respectively. The average length of stay was reported by surgeons to be highest for patients undergoing total parathyroidectomy (2.6 days), followed by exploration for cancer (2.2 days), subtotal parathyroidectomy (1.9 days), and removal of adenoma(s) (1.2 days). On average,

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Surgery Volume 124, Number 6 Table VI. Other inputs with their base estimate probabilities and costs Components of surgical management model for primary HPT

Base case estimates Mean (range)

In-hospital Subtotal parathyroidectomy (adenoma) Surgeon fee Anesthesia fee Total parathyroidectomy (with autotransplantation) Surgeon fee Anesthesia fee Pathology consultation* Endocrinology consultation† Postoperative surveillance Office visits to surgeon Office visits to primary physician Serum calcium‡ Intact PTH‡ Chemistry panel‡ BUN/creatinine‡ 24-h urine calcium Creatinine clearance‡ Bone densitometry

2.2 (1-9) 1.7 (0-5) 2.3 (0-5) 1.2 (0-11) 1.1 (0-4) 0.7 (0-3) 0.4 (0-1) 0.4 (0-1) 0.7 (0-3)

Source (reference)

Unit cost ($) 3308 1178 1126 4309

Discharge abstract registry, 14 14 AAES survey, 14 Discharge abstract registry, 14

1472 1677 98 95

14 AAES survey, 14 Expert estimate, 14 Expert estimate, 14

Global fee 37.71 10.39 61.58 15.81 10.39 8.57 16.41 210.93

AAES survey, 14 AAES and endocrinologist surveys, 14 AAES survey, 14 AAES survey, 14 AAES survey, 14 AAES survey, 14 AAES survey, 14 AAES survey, 14 AAES survey, 14

PTH, Parathyroid hormone; BUN, blood, urea, nitrogen. *Includes initial in-hospital consultation. †Includes intraoperative consultation and permanent section. ‡Includes fee for venipuncture.

Table VII. Resource use patterns among endocrine surgeons for surgical management of primary hyperparathyroidism Cost per patient ($) Resource use Average case Primary operation Reoperation Overall Low use Primary operation Reoperation Overall High use Primary operation Reoperation Overall

Preoperative

Total US cost (million $)

In-hospital

Postoperative

Total

130 349

7066 7312

271 271

7467 7932

275.0 6.7 281.7

100 180

6310 6547

122 122

6532 6849

240.6 5.8 246.4

141 432

7796 8033

508 508

8445 8973

311.0 7.5 318.5

6.1% of patients with primary hyperparathyroidism whose underlying disease was an adenoma avoided an overnight hospital stay. These differences in length of stay were associated with variation in hospital charges. Both outcomes were determined largely by the extent of the surgical procedure that was performed for primary hyper-

parathyroidism (Table VI). For example, with professional fees for anesthesiology included, the cost of total parathyroidectomy ($7390) was nearly $2000 more than the cost of removal of a parathyroid adenoma or other subtotal parathyroidectomy ($5815). There also was significant variation among endocrine surgeons in their patients’ average total

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resources, and 70% of the difference would stem from variation in in-hospital costs. The estimated annual cost of performing parathyroidectomy for primary hyperparathyroidism in the United States is $282 million. Based on our sensitivity analysis estimates, the cost would be very different (13% compared with the average case estimate) if the practice patterns of endocrine surgeons who are either high or low users of health-care resources were uniformly adopted on a national level.

Fig 2. In-hospital costs by type of surgical procedure represent in-patient services and professional fees for surgeon, anesthesiologist, pathologist, and endocrinologist. Bars, Range of reported costs, with mean value indicated.

hospital costs (Fig 2). For example, in-hospital costs of endocrine surgeons with high-resource use were 21% higher than those for endocrine surgeons with average use for subtotal parathyroidectomy (removal of adenoma[s]) and 33% higher than those for total parathyroidectomy. Postoperative surveillance of patients with primary hyperparathyroidism with laboratory tests and clinic visits was also characterized by variation in practice patterns (Table VI). For example, the number of postoperative office visits to the surgeon varied from 1 to 9, with an average of 2 visits, whereas the number of intact parathyroid hormone tests (each of which costs $62) varied from 0 to 11. However, these inputs were relatively inexpensive and accounted for less of the overall variation in costs nationally than did the in-hospital component of surgical management. It is notable that there was a subgroup of 23 endocrine surgeons (21%) who demonstrated a pattern of high use of resources across at least 4 of the 12 measures of intensity of use of preoperative localization, in-hospital services, and postoperative surveillance. There did not appear to be an association between degree of penetration of managed care and patterns of use of resources. Estimates of national expenditures. Although there was variation in preoperative and postoperative practice patterns, in-hospital costs and physician professional fees had the greatest influence on the total cost of the surgical management of primary hyperparathyroidism (Table VII). For example, overall cost per patient undergoing a primary operation, assuming average use of resources, was about $7500. This cost could be $1000 lower or higher based on assumptions of alternative use of

DISCUSSION There is significant variation in the surgical management of patients with asymptomatic and minimally symptomatic primary hyperparathyroidism among even a highly experienced group of endocrine surgeons. A lack of consensus about optimal practice patterns appears to characterize the preoperative, in-hospital, and postoperative phases of care. Our estimates suggest that this variation could result in significantly increased costs for individual patients, their insurers, and society. They also raise the specter of inconsistent quality of care. In addition, these findings suggest that endocrinologists and endocrine surgeons are either not aware of the practice guidelines outlined in the NIH Consensus Development Conference Statement or are intentionally not following them. If this is the case, it raises the question of whether the guidelines are obsolete and need to be updated with evidencebased recommendations. For example, the NIH Consensus Development Conference concluded that preoperative localization is not indicated in patients with asymptomatic primary hyperparathyroidism who have not undergone exploration. In contrast, the Development Conference recommended that patients who have undergone previous exploration should undergo localization routinely.7 However, the NIH guidelines were published before the development of sestamibi scanning for parathyroid localization or outpatient parathyroid exploration. According to our survey, nearly half of patients who have not undergone exploration are referred for parathyroidectomy with a localization study ordered by their referring physician, and more than 40% of surgeons obtain a study before exploration. Although there was agreement between surgeons and referring physicians that sestamibi should be the first-line study of choice, there was a moderate degree of support for alternative modalities. This disagreement about optimal practice reflects debate that is ongoing in the literature.18-20 The cost of preoperative localization studies varies by more than a factor of 6; the cost of an ultra-

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sound examination is $80, sestamibi is $155, and magnetic resonance imaging or venous sampling is more than $475. It is clear that variation in strategies for obtaining preoperative localization studies has significant cost implications. This study has several possible limitations. Because many of the results are based on self-reports, there is the potential for reporting bias even though respondents were assured that results would be kept confidential. There is also the potential for selection bias among our sampling frame, although respondents and nonrespondents appeared to be similar. In addition, there is the question of whether our results are generalizable beyond the endocrine surgeons and endocrinologists who were surveyed. The lack of consensus about optimal management strategies is particularly striking, given that survey respondents represent highly experienced endocrine surgeons. The survey results and subsequent estimates of costs in the United States almost certainly underestimate the variation in practice patterns that exists in the broader medical community, where surgeons generally have less experience caring for patients with primary hyperparathyroidism. Finally, it would have been optimal to have built into the analysis estimates of patient preferences, costs of medical management, and other outcomes (eg, patients’ functional status) to determine whether more expensive surgical management results in a higher quality of care. This cost-identification analysis is only a first step in understanding current practice patterns to define the indications for management strategies and to guide appropriate and cost-effective care of patients with primary hyperparathyroidism. The results of this study have important implications for patients, surgeons, and referring physicians who must decide where to send their patients with primary hyperparathyroidism for operations, as well as third-party payers and policy makers who are responsible for setting medical coverage and reimbursement strategies. We thank Eugene Yoon, BA, for his assistance in conducting the facsimile distribution of the surveys and data entry and Kanwal Minhas, MBA, Senior Financial Analyst/Manager in the Department of Anesthesiology and Critical Care Medicine at the Johns Hopkins Hospital, for her assistance in the analysis of professional fees in anesthesia. REFERENCES 1. Al Zahrani A, Levine MA. Primary hyperparathyroidism. Lancet 1997;349:1233-8. 2. Mundy G, Cove D, Fisken R. Primary hyperparathyroidism: changes in the pattern of clinical presentation. Lancet 1980;1:1317-20. 3. Heath H, Hodgson SF, Kennedy MA. Primary hyper-

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parathyroidism: incidence, morbidity, and potential impact in a community. N Engl J Med 1980;302:189-93. Stenstrom G, Heedman PA. Clinical findings in patients with hypercalcaemia: a final investigation based on biochemical screening. Acta Med Scand 1974;195:473-7. Wermers R, Khosla S, Atkinson E, Hodgson S, O’Fallon W, Melton LI. The rise and fall of primary hyperparathyroidism: a population-based study in Rochester, Minnesota, 1965-92. Ann Intern Med 1997;126:433-40. Horowitz M, Wishart JM, Need AG, Morris HA, Nordin BEC. Primary hyperparathyroidism. Clin Geriatr Med 1994;10:757-75. Gaz RD, Wang C-A. Management of asymptomatic hyperparathyroidism. Am J Surg 1984;147:498-502. Potts JT. Management of asymptomatic hyperparathyroidism. J Clin Endocrinol Metab 1990;70:1489-93. Sosa JA, Powe NR, Levine MA, Udelsman R, Zeiger MA. Thresholds for surgery and surgical outcomes for patients with primary hyperparathyroidism: a national survey of endocrine surgeons. J Clin Endocrinol Metab 1998;83:265865. Potts JT, editor. Proceedings of the NIH Consensus Development Conference on diagnosis and management of asymptomatic primary hyperparathyroidism. J Bone Miner Res 1991;6:S9-13. Chen H, Parkerson S, Udelsman R. Parathyroidectomy in the elderly: do the benefits outweigh the risks? World J Surg 1998;22531-6. Health Care Financing Administration, OACT, Office of National Health Statistics. Washington, DC: DRI/McGraw Hill HCC; 1995. Finkler SA. The distinction between cost and charges. Ann Intern Med 1982;96;102-9. Clinical lab fee schedule for Baltimore, Maryland, metropolitan area, Medicare part B newsletter no. 014, Nov 30, 1996. Anderson RN, Kochanek KD, Murphy SL. Report of final mortality statistics, 1995. In: Monthly vital statistics report, 45(11S2). Hyattsville (MD): National Center for Health Statistics; 1997. p 76. Salti G, Fedorak I, Yashiro T, Fulton N, Hara H, Yousefzadeh D, et al. Continuing evolution in the operative management of primary hyperparathyroidism. Arch Surg 1992;127:831-7. Rudberg C, Akerstrom G, Palmer M, Ljunghall S, Adami H, Johansson H, et al. Late results of operation for primary hyperparathyroidism in 441 patients. Surgery 1986;99:643-51. Udelsman R. Parathyroid imaging: the myth and the reality. Radiology 1996;201:317-8. Krubsack AJ, Wilson SD, Lawson TL, Kneeland JB, Thorsen MK, Collier BD, et al. Prospective comparison of radionuclide, computed tomographic, sonographic, and magnetic resonance localization of parathyroid tumors. Surgery 1989;108:639-46. Miller DL. Pre-operative localization and interventional treatment of parathyroid tumors: when and how? World J Surg 1991;15:706-15.

DISCUSSION Dr Lawrence A. Danto (Sacramento, Calif). If we are interested primarily in cost control, of course we want to eliminate variation. If we are interested primarily in quality care, we must accept variation. Coming from the birthplace of capitated managed care, I would ask you this: Did you consider the type of third-party payment as a cause of variation or lack of variation in your study?

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Dr Sosa. We measured the amount of variation in the health care environments of the surgeons included in our survey by asking about the degree of penetration of managed care in their area. With that variable used in the multivariate regression analysis, we found that it was not associated with the outcomes we are discussing today. Dr James Norman (Tampa, Fla). We published a large cost-analysis article1 analyzing 6631 patients. We showed that there was only 1 variable that determined the cost effectiveness of these operations: the surgeon’s choice of the operative approach. This was not mentioned in your presentation. I have several comments and a question. The first comment is regarding the NIH Consensus Report in 1991. Sestamibi scanning was not available, so it was not evaluated. Second, you did not look at the number of frozen sections performed. That is clearly a cost of this operation. Some surgeons do many frozen sections and others do none. Third, we have found that the only way to make a difference in cost is to operate on only 1 side of the neck under local anesthesia and then send the patient home. If you do not do that, it does not matter what preoperative scan you do; it is costly. If you can operate on 51% of the patients on 1 side of the neck, it is cost effective to do preoperative localization studies. Could you address the operative technique in more detail? REFERENCE 1. Denham D, Norman J. Cost-effectiveness of preoperative sestamibi scan for primary hyperparathyroidism is dependent solely upon surgeons’ choices of operative procedure. J Am Coll Surg 1998;186:293-304.

Dr Sosa. We are looking at this cost-identification analysis as the initial step to the development of a cost-effec-

Surgery December 1998 tiveness and decision analysis. We can build in variables that were not discussed today but may be important to the overall analysis. These variables include the costs of alternative medical therapies and surveillance, as well as patient choice and preferences. This study was limited, but again it is just a stepping stone to further studies. In terms of your second point, we made a variety of assumptions about the number of frozen sections and found it did not affect the overall findings of the study because its value was small relative to the values of other variables. Last, we come to the most difficult question, and that is surgeons’ choice. In our survey we did not ask surgeons about their motivations for choice of operation. The administrative database we used permits only retrospective analysis, and it was impossible to get at those motivating factors. However, surgeon volume was found to be significantly associated with quality-of-care measures, including patients’ hospital length of stay, in-hospital complications (both minor and major), and in-hospital deaths. Dr William Barry Inabnet (New York, NY). I applaud your study because it examines 1 of the central issues of parathyroid operations (ie, the cost of different surgical strategies). In my experience the unilateral approach under local anesthesia appears to be the most cost-effective approach because you forgo the need for general anesthetics and all the obligatory preoperative testing. Operating time is markedly reduced. Patients are discharged the same day of operation and the only postoperative laboratory work needed is serum calcium and parathyroid hormone testing 1 week and 6 months after the operation. This is the most cost-effective approach. Dr Sosa. It is with great vigor and enthusiasm that we try to build the cost-effectiveness analysis.