A new study has examined US geographical variations in cost for anterior cervical discectomy and fusion (ACDF) and lumbar posterolateral fusion (PLF). The study found that the Midwest recorded the lowest cost for PLF with the highest costs in the Northeast, and that the cost of procedures correlated with the average cost of living in each state, though not with the state’s total population. The cost of ACDF procedures was not significantly different between regions.
Published ahead-of-print by the journal Spine, the study was led by Vadim Goz and colleagues at the University of Utah, Salt Lake City, USA.
The authors write that an estimated 3.6 million spinal fusions were performed in the USA between 2001 and 2010, associated with over $287bn in total charges. The high prevalence of spine disease in the USA and the prevalence of spinal fusion surgery “increases the importance of optimising value in this group of procedures”. In this study, value was defined as the ratio of an intervention’s benefit to the patient and the intervention’s cost. Goz and colleagues also compared the cost variation seen in ACDFs and PLFs to that seen in total knee replacements in order to clarify whether these trends are specific to spine surgery or extend across orthopaedics.
A number of studies have previously investigated the total charges associated with these procedures, using total charges to estimate the costs of the operations. This is the first study to use actual Medicare reimbursement data from the Medicare Provider Utilisation and Payment dataset, allowing direct investigation of costs, as opposed to estimating costs from total charges. Goz et al believe that defining costs is integral to cost effectiveness analyses and ultimately the delivery of value-based care. “These data will be an invaluable addition for future cost-effectiveness studies,” they write. “The data will also provide future areas of study by identifying states that have succeeded in delivering healthcare at a lower cost.”
The total costs, combining professional level fees, ranged broadly across the USA. Combined professional and facility costs for a single level ACDF, with instrumentation, no interbody cage, and no bone grafting through a separate incision, had a national mean of US$13,899 (range of US$14,044). Total costs for a single level lumbar PLF, with posterior instrumentation, and no bone grafting, hand a mean cost of US$25,858 (range US$17,437).
Analysis of geographic trends showed statistically significant differences in total costs of PLF, between geographic regions (p<0.01 for all), the Northeast having the highest average costs (US$28,348), with lowest cost in the Midwest (US$24,096). This is notable as the Midwest is associated with the highest salaries for spinal surgeons, according to the 2010 MGMA report. No statistically significant differences in total costs of ACDF (US$13,899) were found between geographic regions (p=0.105). The total costs of both groups showed a statistically significant correlation to a state’s cost of living index (p<0.0001 for all groups). Conversely, neither of the groups showed a statistical association between total cost and state population; ACDF (p=0.63) and PLF (p=0.804). Similar geographic trends in the cost of spinal fusions and total knee replacements suggests that these trends may not be limited to just spine related procedures.
Further investigation revealed that the costs of the procedures analysed “had no correlation with a state’s population”. However, there was strong correlation between procedure cost and a state’s cost of living, although the cost of living did not fully explain trends in cost. “For example,” Goz et al write, “Utah and Wyoming are bordering states with comparable costs of living (cost index 93 and 93.2, respectively). Wyoming was in the top 10 most expensive states for the procedures investigated while Utah was consistently amongst the 10 least expensive states.”
The authors reported another potential hurdle involved in cost-effectiveness research and defining a procedure’s value, with significant variations in costs across the country for the procedures investigated. “The cost of ACDF procedures varied by 129% from the least to most effective states and 87% for PLF,” Goz and colleagues write. “Accounting for this variation is vital in calculating value and quality-adjusted life years, as this data suggests that a procedure will vary in cost effectiveness in different states due to variation in cost.”
“This data sheds light on the actual cost of common surgeries throughout the United States and will allow further progress towards the development of cost effective, value driven care,” the study team conclude.