Ambulatory Surgery Center Market Share and Rates of Outpatient Surgery in the Elderly

Abstract

Relative to outpatient surgery in hospital settings, ambulatory surgery centers (ASCs) are more efficient and associated with a lower cost per case. However, these facilities may also spur higher overall procedure utilization and thus lead to greater overall health care costs. The authors used the State Ambulatory Surgery Database from the State of Florida to identify Medicare-aged patients undergoing 4 common ambulatory procedures in 2006, including knee arthroscopy, cystoscopy, cataract removal, and colonoscopy. Hospital service areas (HSAs) were characterized according to ASC market share, that is, the proportion of residents undergoing outpatient surgery in these facilities. The authors then examined relationships between ASC market share and rates of each procedure. Age-adjusted rates of ambulatory surgery ranged from 190.5 cases per 1000 to 320.8 cases per 1000 in HSAs with low and high ASC market shares, respectively (P < .01). For all 4 procedures, adjusted rates of procedures were significantly higher in HSAs with the highest ASC market share. The greatest difference, both in relative and absolute terms, was observed for patients undergoing cystoscopy. In areas of high ASC market share, the age-adjusted rate of cystoscopy was nearly 3-fold higher than in areas with low ASC market share (34.5 vs 11.9 per 1000 population; P < .01). The presence of an ASC is associated with higher utilization of common outpatient procedures in the elderly. Whether ASCs are meeting unmet clinical demand or spurring overutilization is not clear.

Keywords

ambulatory surgery centers health care utilization physicians’ practice patterns

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References

American Hospital Association. TrendWatch Chartbook 2006: Trends affecting hospitals and health systems. http://www.aha.org/aha/research-and-trends/chartbook/2006chartbook.html. Accessed January 5, 2009.

American Hospital Association. TrendWatch Chartbook 2008: Trends affecting hospitals and health systems. http://www.aha.org/aha/research-and-trends/chartbook/index.html. Accessed January 1, 2009.

Ambulatory Surgery Center Association. Meeting America’s surgical needs. http://www.ascassociation.org/masn.pdf .Accessed January 15, 2009.

MedPAC. Report to Congress: Medicare payment policy. http://www.medpac.gov/documents/Mar04_Entire_reportv3.pdf. Accessed January 12, 2009.

Casalino LP , Devers KJ , Brewster LR Focused factories? Physician-owned specialty facilities. Health Aff (Millwood). 2003;22:56-66.

Shactman D. Specialty hospitals, ambulatory surgery centers, and general hospitals: charting a wise public policy course. Health Aff ( Millwood). 2005;24:868-873.

Centers for Medicare & Medicaid Services. Ambulatory surgical center fee schedule fact sheet. http://cms.meridianksi.com/kc/pfs/pfs_lnkfrm_fl.asp?lgnfrm=reqprod&function=pfs. Accessed March 13, 2009.

Ambulatory Surgery Center Association. Ambulatory surgery centers: a positive trend in health care. http://ascassociation.org/advocacy/AmbulatorySurgeryCentersPositiveTrendHealthCare.pdf . Accessed January 12, 2009.

Bian J. , Morrisey MA Free-standing ambulatory surgery centers and hospital surgery volume. Inquiry. 2007;44: 200-210.

10.

Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project (HCUP). Introduction to the HCUP State Ambulatory Surgery Databases (SASD). http://www.hcup-us.ahrq.gov/db/state/sasddist/Introduction_to_SASD.pdf. Accessed February 6, 2009.

11.

Wennberg JE The Dartmouth Atlas of Healthcare. Chicago, IL: American Hospital Publishing; 1996.

12.

Baldwin FD Where Medicare goes . . . the rest of the system may well follow CMS pay-for-performance example. Healthc Inform. 2004;21:24-26.

13.

American Medical Association. Current Procedure Terminology. CPT 2005, Standard Edition. Chicago, IL: AMA; 2004.

14.

Russo CA , Owens P. , Steiner C. , Josephsen J. Ambulatory surgery in U.S. hospitals, 2003. HCUP fact book no. 9. http://www.ahrq.gov/data/hcup/factbk9 . Accessed November 6, 2008.

15.

Centers for Medicare & Medicaid Services. Medicare utilization for Part B: top 200 Level I Current Procedural Terminology for CY 2007 ranked by charges. http://www.cms.hhs.gov/MedicareFeeforSvcPartsAB/04_MedicareUtilizationforPartB.asp#TopOfPage . Accessed January 30, 2009.

16.

Meddings DR , McGrail KM , Barer ML , et al. The eyes have it: cataract surgery and changing patterns of outpatient surgery. Med Care Res Rev. 1997;54:286-300.

17.

Weinstein JN , Bronner KK , Morgan TS , Wennberg JE Trends and geographic variations in major surgery for degenerative diseases of the hip, knee, and spine. Health Aff (Milwood). 2004;Suppl Web Exclusives:VAR81-89.

18.

Cooper GS , Koroukian SM Geographic variation among Medicare beneficiaries in the use of colorectal carcinoma screening procedures. Am J Gastroenterol. 2004;99: 1544-1550.

19.

U.S. Census Bureau. ZIP code tabulation areas (ZCTAs). http://www.census.gov/geo/ZCTA/zcta.html . Accessed February 6, 2009.

20.

Besanko D. , Dranove D. , Shanley M. , et al. Economics of Strategy. 4th ed. New York, NY: John Wiley; 2006.

21.

Giannini D. Pros and cons of the ambulatory surgery center joint venture. Orthop Clin North Am. 2008;39:11-15.

22.

Berenson RA , Bodenheimer T. , Pham HH Specialty-service lines: salvos in the new medical arms race. Health Aff (Millwood ). 2006;25:w337-w343.

23.

Mcguire TG Physician agency. In: Culyer AJ, Newhouse JP, eds. Handbook of Health Economics . Vol 1A. Amsterdam, Netherlands: Elsevier Science; 2000:461-535.

24.

McGuire TG , Pauly MV Physician response to fee changes with multiple payers. J Health Econ. 1991;10:385-410.

25.

Mitchell JM Do financial incentives linked to ownership of specialty hospitals affect physicians’ practice patterns? Med Care. 2008;46:732-737.

26.

Mitchell JM , Scott E. Physician ownership of physical therapy services: effects on charges, utilization, profits, and service characteristics. JAMA. 1992;268:2055-2059.

27.

Levin DC , Rao VM , Parker L. , Frangos AJ , Sunshine JH Ownership or leasing of MRI facilities by nonradiologist physicians is a rapidly growing trend. J Am Coll Radiol. 2008;5:105-109.

28.

Conover CS , Sloan FA Evaluation of Certificate of Need in Michigan. Vol 2. Durham, NC: Center for Health Policy, Law and Management, Terry Sanford Institute of Public Policy, Duke University; 2003. Appendix B: Table B-2.