Trends in the use and cost of chiropractic spinal manipulation under Medicare Part B.

BACKGROUND CONTEXT: Concern about improper payments to chiropractic physicians prompted the US Department of Health and Human Services to describe chiropractic services as a "significant vulnerability" for Medicare, but little is known about trends in the use and cost of chiropractic spinal manipulation provided under Medicare.
PURPOSE: To quantify the volume and cost of chiropractic spinal manipulation services for older adults under Medicare Part B and identify longitudinal trends. STUDY DESIGN/
SETTING: Serial cross-sectional design for retrospective analysis of administrative data. PATIENT SAMPLE: Annualized nationally representative samples of 5.0 to 5.4 million beneficiaries. OUTCOME MEASURES: Chiropractic users, allowed services, allowed charges, and payments.
METHODS: Descriptive statistics were generated by analysis of Medicare administrative data on chiropractic spinal manipulation provided in the United States from 2002 to 2008. A 20% nationally representative sample of allowed Medicare Part B fee-for-service claims was merged, based on beneficiary identifier, with patient demographic data. The data sample was restricted to adults aged 65 to 99 years, and duplicate claims were excluded. Annualized estimates of outcome measures were extrapolated, per beneficiary and per user rates were estimated, and volumes were stratified by current procedural terminology code.
RESULTS: The number of Medicare beneficiaries who used chiropractic spinal manipulation grew 13% from 2002 to 2004, remained flat through 2007, and then declined 5% through 2008. An estimated 1.7 million beneficiaries (6.9%) used 18.6 million allowed chiropractic services in 2008. In inflation-adjusted dollars, allowed charges per user increased 4% through 2005 and then declined by 17% through 2008; payments per user increased by 5% from 2002 to 2005 and then declined by 18% through 2008. Expenditures for chiropractic in 2008 totaled an estimated $420 million. Longitudinal trends in allowed claims for spinal manipulation varied by procedure: the relative frequency of treatment of one to two spinal regions declined from 43% to 29% of services, treatment of three to four regions increased from 48% to 62% of services, and treatment of five regions remained flat at 9% of services.
CONCLUSIONS: Chiropractic claims account for less than 1/10th of 1% of overall Medicare expenditures. Allowed services, allowed charges, and fee-for-service payments for chiropractic spinal manipulation under Medicare Part B generally increased from 2002, peaked in 2005 and 2006, and then declined through 2008. Per user spending for chiropractic spinal manipulation also declined by 18% from 2006 to 2008, in contrast to 10% growth in total spending per beneficiary and 16% growth in overall Medicare spending.