Introduction

The discipline of weight loss surgery (WLS)¹is under intense scrutiny due to concern for patient safety. Rapid growth in the numbers of severely obese individuals (BMI 40 kg/m²) (1,2) has led to a concomitant increase in surgeons and facilities providing WLS procedures. In Massachusetts alone, more than 2700 gastric bypass operations were carried out in 2003 compared with fewer than 150 in 1996 (3).

WLS is a complex and challenging undertaking. Many patients present with multiple obesity-related comorbidities, which can sharply increase surgical risk (4). A computerized database program is essential to combine and analyze clinical experience (5). There are several benefits to collecting and centralizing standardized data, including: definition of WLS patient demographics; patient risk stratification and risk prediction at both center-by-center and statewide levels; unit benchmarking and development of effective, state- and center-oriented quality improvement programs; assessment of resource use; and use of data to influence healthcare policy on state and national levels (6).

There is no standardized data collection system or registry for WLS in Massachusetts (or any other state) at this time, nor is there any research on whether such a system improves patient safety and outcomes. Related evidence, especially from the field of cardiac surgery, suggests that regional or national risk-adjusted data collection systems may contribute to improved patient safety and decreased surgical mortality rates (5,6). This report examines the efficacy and utility of databases for WLS and other surgical fields as they pertain to patient safety, medical error reduction, systems improvement, and research needed for the future. It assesses WLS data collection systems now under development and provides a basic framework for creating a comprehensive, statewide WLS data collection system.

Research Methods and Procedures

We performed two systematic searches of literature published in MEDLINE from January 1980 to March 2004. Few studies were found on the presence, efficacy, or utility of data collection systems and registries in the field of WLS. To compensate for the lack of data, we broadened our search to include data collection systems and registries from related fields (e.g., cardiac and thoracic surgery), and cancer data registries. Over 150 articles were identified; 14 were reviewed in detail.

These included studies from single institutions, discharge abstract databases, the Swedish Obese Subjects (SOS) Study (7,8), and the International Bariatric Surgery Registry (IBSR) (9). Each article was reviewed and assigned a level of evidence using a grading system based on well-established models (10). Most of the evidence was Category B. Recommendations are based on the best available evidence and expert opinion.

Results

Collection of WLS Data: Current Situation

Academic, government, and private entities collect WLS data, but there appears to be only one established centralized database in the United States—the IBSR (11). Developed at the University of Iowa College of Medicine in 1979 to promote optimum care of WLS patients (9), the IBSR provides members with standardized clinical data collection and analysis, including individual and pooled reports.

A 1999 IBSR study compared information from 32,434 patients whose primary operations for severe obesity were performed from 1986 to 2001 by National Bariatric Surgery Registry- and IBSR-contributing surgeons (76 data collection sites and 111 surgeons). The IBSR 2002 Pooled Summer Report included data from 17,767 patients whose primary WLS occurred between 1986 and 2002 (9). The cumulative number of patient records for IBSR pooled reports has grown from 242 for the first report in 1986 to over 20,000 in 1999 (11).

The NIH, working with six clinical centers and a data coordinating center, has recently established the Longitudinal Assessment of Bariatric Surgery (LABS) (12) to plan, develop, and conduct coordinated clinical, epidemiological, and behavioral research on WLS through the development of common clinical protocols and a WLS database. The goal of LABS is to standardize definitions and data collection instruments across different centers and to study the risks and benefits of different WLS procedures.

The American Society for Bariatric Surgery (ASBS) (13), through its not-for-profit Surgical Review Corporation (SRC) (4), is developing a data capture system for its Centers for Excellence program, which requires participating centers to standardize surgical procedures and care plans, meet outcomes data requirements, and include all patients in their databases. SRC plans to use its database for research, especially risk stratification, comparison of WLS procedures, and assessment of care plans (4).

Data on WLS outcomes are collected using software from private companies (e.g., RemedyMD, www.remedymd.com) and through studies at single institutions (14,15,16,17), usually high-volume specialized centers. They are also collected though large cohort studies. The SOS study, a prospective matched cohort study of 4047 obese subjects randomized to either surgical intervention or control, offers a unique possibility for investigating the long-term effects of WLS in obese subjects (8,18).

Evidence-Based Statement:

A WLS data collection system is feasible and useful. LABS and other databases could serve as models for a statewide WLS registry (Category D).

Other WLS Data Collection Studies

Outcomes of WLS have been characterized retrospectively at the state level using hospital discharge data in California (19) and at the national level with the National Inpatient Sample (20). Flum et al. (21), in a recent population-based study of hospital discharge data of WLS patients, found significantly higher statewide 30-day mortality rates than those reported by single institutions.

Evidence-Based Statement:

Large discrepancies in statewide vs. single-institution mortality rates underscore the need for accurate population-based WLS information (Category D).

Data Collection and Outcomes in Other Medical Fields: Current Situation

No medical discipline as been more shaped, driven, and scrutinized by outcomes data than cardiac surgery (22). The New York State Department of Public Health has mandated prospective, risk-adjusted, standardized, surgeon- and institution-specific reporting of outcomes for Coronary Artery Bypass Grafting since 1989 (23). Data suggest a possible association between public reporting of outcomes data and a 41% decrease in mortality during the period from 1989 to 1992 (i.e., the first 3 years after data collection started) (23). O'Connor et al. (24) also found a significant reduction in hospital mortality rates when outcome data were used as part of a continuous quality improvement intervention study (i.e., the Northern New England Cardiovascular Disease Study Group).

The National Surgical Quality Improvement Program (NSQIP)—a nationally validated, outcome-based, risk-adjusted, and peer-controlled program for understanding and improving clinical care in major surgical specialties (25)—has reduced morbidity rates in Veterans Affairs Hospitals. Since the inception of NSQIP in 1994, the VA has reported consistent improvements in all surgery performance measures (26). The NSQIP methodology has been found feasible for use in private sector hospitals (26,27). The American College of Surgeons (ACS) (28,29) plans to implement the NSQIP model as a national platform for collection of surgery data.

Evidence-Based Statement:

Institutions that participate in regional or national risk-adjusted data collection systems show improved quality of care, a decreased number of outlier institutions, and a greater decrease in surgical mortality rates compared with national averages (23,24,25,26,30,31,32) (Category B).

Rationale for a WLS Database

Increasingly, pooled data from multiple institutions are the source of published results on clinical outcomes (5). The collection of surgical data for institutional quality improvement and patient safety analysis also satisfies a growing need to report detailed clinical information to such programs as the NSQIP/Patient Safety in Surgery/Private Sector Study (33).

Other considerations are:

• WLS is a high-risk procedure performed in high-risk patients, but these risks are not fully characterized.
• Risk may be greater than expected; Flum et al. (21) suggest that the population-based mortality rate from WLS is four times that reported in single-institution studies.
• There is rapid growth in demand for gastric bypass operations, an increase of nearly 600% in 5 years in Massachusetts (3).
• Novel approaches and technologies, such as laparoscopic adjustable gastric band and laparoscopic gastric bypass, need to be monitored for safety and efficacy; intraluminal and endoscopic techniques are likely to be introduced in the near future.
• Public concern about the safety of WLS procedures is intense. Demand for accurate and current information comes from multiple sources, including patients; the public; surgeons; researchers; insurers, HMOs, and hospital administrators; risk management companies; and regulatory commissions.

System and Data

Mavroudis et al. (34) suggest that standardized data collection schemes and data validation programs—mandated on a state, regional, or national level—result in improved data quality and uniform participation by centers. They also suggest that a comprehensive data set includes as many variables as possible, in a hierarchical scheme, detailed enough to generate risk stratification analyses. Williams et al. (5) suggest that the scope of data collection defines a database and that resources dedicated to data collection and entry are the practical limit to the extent of information in the database.

Recommendation:

This task group recommends that a committee be formed to advise the Department of Public Health on the development of a statewide data collection system for all programs, centers, and institutions that perform WLS (35) (Category D). The committee should advise whether participation in a statewide WLS data collection system be mandatory for all centers that perform WLS.

Recommendations (Category D):

• That the data collection system be confidential, prospective, risk-adjusted, multicenter, benchmarked, and based on standard definitions of data points;
• That data include preoperative, intraoperative, postoperative, and long-term follow-up information (Table 1) (35); and
• That data be collected by a sophisticated, trained, unbiased, and audited reviewer.

Table 1. - Appropriate data for a WLS database.

Full table

Future Research

This task group believes that a mandatory statewide data collection system for WLS programs would promote continuous quality improvement and enhance patient safety (Table 2). However, the development of such a system raises many questions (Table 3) and poses many challenges (6).

Table 2. - Evidence for the efficacy of data collection systems.

Full table

Table 3. - Database development questions and issues.

Full table

Recommendations (Category D):

• That a committee be formed to examine such issues as standardization of the data collection system, the possibility of a tiered system (35), and a combined adolescent/adult database;
• That a pilot study that involves hospitals from community health centers and academic medical centers be set up to beta-test any proposed system; and
• That a feasibility study be carried out to address not only the complexities of such a system but also the financial impact on participating centers.

Discussion

Because WLS is increasingly common, overall death may increase even if the risk associated with each individual procedure decreases. Postoperative mortality is thought to range from as low as 0.1% to as high as 1% to 2%. Because there is no comprehensive registry, it is difficult to obtain accurate data about the specific rates of serious complications and deaths that can be anticipated and that may occur even with excellent care (36).

Between 1998 and 2003, the ASBS membership of practicing surgeons increased from 258 to 1070 (36). The number of gastrointestinal surgeries performed annually for severe obesity rose from 16,000 in the early 1990s to 103,000 in 2003 (36). As demand for WLS continues to increase, so will the level of scrutiny placed on providers and facilities. A well-conceived and comprehensive data collection system will enable the use of predictive modeling, risk-adjusted comparison, and other powerful data analysis techniques to identify best practices in WLS, improve patient outcomes, and address questions and concerns with accurate, timely, and complete data.

Notes

¹ Nonstandard abbreviations: WLS, weight loss surgery; SOS, Swedish Obese Subjects; IBSR, International Bariatric Surgery Registry; LABS, Longitudinal Assessment of Bariatric Surgery; ASBS, American Society for Bariatric Surgery; SRC, Surgical Review Corporation; NSQIP, National Surgical Quality Improvement Program; ACS, American College of Surgeons.

References

1. Flegal, K. M., Carroll, M. D., Kuczmarski, R. J., Johnson, CL. (1998) Overweight and obesity in the United States: prevalence and trends, 1960-1994. Int J Obes Relat Metab Disord. 22: 39–47. | Article | PubMed | ChemPort |
2. Flegal, K. M., Carroll, M. D., Ogden, C. L., Johnson, CL. (2002) Prevalence and trends in obesity among US adults, 1999-2000. JAMA 288: 1723–1727. | Article | PubMed | ISI |
3. Lehman Center Weight Loss Surgery Expert Panel (2005) Expert Panel on Weight Loss Surgery Executive Report. Obes Res. 13: 205–226. | ISI |
4. SRC The Bariatric Surgery Centers of Excellence Program http://www.surgicalreview.org/ (accessed October 1, 2004).
5. Williams, W. G., McCrindle, BW. (2002) Practical experience with databases for congenital heart disease: a registry versus an academic database. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 5: 132–142.
6. Wyse, R. K., Taylor, KM. (2002) Using the STS and multinational cardiac surgical databases to establish risk-adjusted benchmarks for clinical outcomes. Heart Surg Forum. 5: 258–264.
7. Karlsson, J., Sjöström, L., Sullivan, M. (1995) Swedish Obese Subjects (SOS)–an intervention study of obesity: measuring psychosocial factors and health by means of short-form questionnaires: results from a method study. J Clin Epidemiol. 48: 817–823. | Article | PubMed | ISI | ChemPort |
8. Sjöström, CD. (2003) Surgery as an intervention for obesity. Results from the Swedish obese subjects study. Growth Horm IGF Res. 13: S22–S26. | Article | PubMed |
9. Mason, E. E., Tang, S., Renquist, K. E., et al (1997) A decade of change in obesity surgery: National Bariatric Surgery Registry (NBSR) Contributors. Obes Surg. 7: 189–197. | PubMed |
10. U.S. Preventive Services Task Force (1996) Guide to Clinical Preventive Services 2nd ed. Williams & Wilkins Baltimore, MD.
11. IBSR Patient Outcome Research for Surgical Treatment of Obesity: The University of Iowa Hospitals and Clinics, Department of Surgery, College of Medicine: August 11, 2004 http://www.surgery.uiowa.edu/ibsr/ibsrbroc2000.html (accessed October 1, 2004).
12. U.S. Department of Health and Human Services LABS: August 2004 http://winn.iddk.nih.gov/publications/labs/labs804.pdf (accessed November 15, 2004).
13. ASBS (2004) http://www.asbs.org/ (accessed October 1, 2004).
14. Schauer, P. R., Ikramuddin, S., Gourash, W., et al (2000) Outcomes after laparoscopic Roux-en Y gastric bypass for morbid obesity. Ann Surg. 232: 515–529. | Article | PubMed | ISI | ChemPort |
15. Higa, K. D., Ho, T., Boone, KB. (2001) Laparoscopic Roux -en-Y gastric bypass: technique and 3-year follow-up. J Laparoendosc Adv Surg Tech. 11: 377–382.
16. Schauer, P., Ikramuddin, S., Hamad, G., Gourash, W. (2003) The learning curve for laparoscopic Roux-en-Y gastric bypass is 100 cases. Surg Endosc. 17: 212–215. | Article | PubMed | ChemPort |
17. Wittgrove, A. C., Clarke, GW. (2000) Laparoscopic gastric bypass, Roux-en-Y-500 patients: technique and results with 3-60 month follow-up. Obes Surg. 10: 233–239. | Article | PubMed | ChemPort |
18. Torgerson, J. S., Sjöström, L. (2001) The Swedish Obese Subjects (SOS) study - rationale and results. Obes Surg. 35: S2–S4.
19. Liu, J. H., Zingmond, D., Etzioni, D. A., et al (2003) Characterizing the performance and outcomes of obesity surgery in California. Am Surg. 89: 823–828.
20. Pope, G. D., Birkmeyer, J. D., Finlayson, SR. (2002) National trends in utilization and in-hospital outcomes of bariatric surgery. J Gastrointest Surg. 6: 855–860. | Article | PubMed | ISI |
21. Flum, D. R., Dellinger, EP. (2004) Impact of gastric bypass surgery on survival: a population-based analysis. J Am Coll Surg. 199: 543–551. | Article | PubMed | ISI |
22. Blackstone, EH. (2004) Let the data speak for themselves? Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 7: 192–198.
23. Hannen, E. L., Kumar, D., Racz, M., Siu, A. L., Chassin, MR. (1994) Improving the outcomes of coronary artery bypass grafting in New York State. JAMA. 271: 761–766. | Article | PubMed | ISI | ChemPort |
24. O'Connor, G. T., Plume, S. K., Olmstead, E. M., et al (1996) A regional intervention to improve the hospital mortality associated with coronary artery bypass graft surgery: the Northern New England Cardiovascular Disease Study Group. JAMA 275: 841–846.
25. Khuri, S. F., Daley, J., Henderson, WG. (2002) The comparative assessment and improvement of quality of surgical care in the Department of Veterans Affairs. Arch Surg. 137: 20–27.
26. Fink, A. S., Campbell, D. A., Mentzer, R. M., et al (2002) The National Surgical Quality Improvement Program in non-Veterans Administration Hospitals: initial demonstration of feasibility. Ann Surg. 236: 344–354.
27. Dimick, J. B., Chen, S. L., Taheri, P. A., Henderson, W. G., Khuri, S. F., Campbell, D. A. Jr (2004) Hospital costs associated with surgical complications: a report from the private-sector National Surgical Quality Improvement Program. J Am Coll Surg. 199: 531–537.
28. ACS ACS NewsScope: August 2004 http://www.facs.org/newsscope/ns082004.html#3 (accessed November 15, 2004).
29. ACS Welcome to the Research Award Database http://web.facs.org/research/index.html (accessed October 2, 2004).
30. Birkmeyer, N. J., Marrin, C. A., Morton, J. R., et al (2000) Decreasing mortality for aortic and mitral valve surgery in Northern New England. Ann Thorac Surg. 70: 432–437.
31. Ferguson, T. B., Dziuban, S. W., Edwards, F. H., et al (2000) The STS National Database: current changes and challenges for the new millennium. Ann Thorac Surg. 69: 680–691.
32. Shahian, D. M., Normand, S. L., Torchiana, D. F., et al (2001) Cardiac surgery report cards: comprehensive review and statistical critique. Ann Thorac Surg. 72: 2155–2168.
33. Sheode, M. M., Miller, C., Merzlak, S., et al (2004) Automation of surgical data collection for quality improvement. Medinfo CD: 1860
34. Mavroudis, C., Jacobs, JP. (2000) Congenital Heart Surgery Nomenclature and Database Project: overview and minimum dataset. Ann Thorac Surg. 69: S2–S17.
35. Kaplan, L., Fallon, J., Mun, E., et al (2005) Coding and reimbursement for weight loss surgery: best practice recommendations. Obes Res 13: 290–300.
36. Steinbrook, R. (2004) Surgery for severe obesity. N Engl J Med. 350: 1075–1079. | Article | PubMed | ISI | ChemPort |

Acknowledgments

We thank George Blackburn and Frank Hu for manuscript preparation, Barbara Ainsley for administrative services, and Rita Buckley for editorial services. Manuscript preparation was supported in part by the Center for Healthy Living at Harvard Medical School and by the Boston Obesity Nutrition Research Center Grant P30DK46200. This report on WLS was prepared for the Betsy Lehman Center for Patient Safety and Medical Error Reduction (Department of Public Health, Boston, MA).