Introduction
This document details the methodology for the Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels measure and should be reviewed along with the Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels Measure Codes List file, which contains the medical codes used in constructing the measure.
Measure Description
Episode-based cost measures represent the cost to Medicare for the items and services provided to a patient during an episode of care (“episode”). In all supplemental documentation, “cost” generally means the standardized1 Medicare allowed amount,2 and claims data from Medicare Parts A and B are used to construct the episode-based cost measures.
The Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels episode-based cost measure evaluates a clinician’s risk-adjusted cost to Medicare for patients who undergo surgery for lumbar spine fusion during the performance period. The measure score is the clinician’s risk-adjusted cost for the episode group averaged across all episodes attributed to the clinician. This procedural measure includes costs of services that are clinically related to the attributed clinician’s role in managing care during each episode from 30 days prior to the clinical event that opens, or “triggers,” the episode through 90 days after the trigger.
Measure Rationale
Between 2006 and 2012, over 6 million Medicare patients were diagnosed with lumbar degenerative conditions,3 and lumbar spine procedures are increasingly used in older adult patients to treat these conditions. One study found that 5.9 per 100 patients progressed to lumbar fusion within one year of diagnosis with lumbar degeneration, and there was an increase of 18.5% in the incidence of fusion procedures within one year of diagnosis.4 Based on a review of the Medicare Provider Analysis and Review file, total spending on lumbar spinal fusion surgery is also one of the highest admission expenditures in the Medicare program, costing over $3.6 billion dollars in 2013.5
The Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels episode-based cost measure was selected for development based on input from an expert clinician committee—the Musculoskeletal Disease Management - Spine Clinical Subcommittee—because of its impact in terms of patient population and clinician coverage, and the opportunity for incentivizing cost-effective, high-quality clinical care in this clinical area. Based on the initial recommendations from the Clinical Subcommittee, the subsequent measure-specific clinician expert workgroup provided extensive, detailed input on this measure.
Measure Numerator
The cost measure numerator is the sum of the ratio of observed to expected6 payment-standardized cost to Medicare for all Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels episodes attributed to a clinician. This sum is then multiplied by the national average observed episode cost to generate a dollar figure.
Measure Denominator
The cost measure denominator is the total number of episodes from the Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels episode group attributed to a clinician.
Data Sources
The Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels cost measure uses the following data sources:
- Medicare Part A and B claims data from the Common Working File (CWF)
- Enrollment Data Base (EDB)
- Long Term Care Minimum Data Set (LTC MDS)7
Care Settings
Methodologically, the Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels cost measure can be triggered based on claims data from: ambulatory surgical centers (ASC), hospital outpatient departments (HOPD), and acute inpatient (IP) hospitals.
Cohort
The cohort for this cost measure consists of patients who are Medicare beneficiaries enrolled in Medicare fee-for-service and who undergo surgery for lumbar spine fusion that triggers a Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels episode.
The cohort for this cost measure is also further refined by the definition of the episode group and measure-specific exclusions (refer to Section 4).
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1 Claim payments are standardized to account for differences in Medicare payments for the same service(s) across Medicare providers. Payment standardized costs remove the effect of differences in Medicare payment among health care providers that are the result of differences in regional health care provider expenses measured by hospital wage indexes and geographic price cost indexes (GPCIs) or other payment adjustments such as those for teaching hospitals. For more information, please refer to the “CMS Part A and Part B Price (Payment) Standardization - Basics" and “CMS Part A and Part B Price (Payment) Standardization - Detailed Methods” documents posted on the CMS Price (Payment) Standardization Overview page. (https://resdac.org/articles/cms-price-payment-standardization-overview).
2 Cost is defined by allowed amounts on Medicare claims data, which include both Medicare trust fund payments and any applicable beneficiary deductible and coinsurance amounts.
3 Buser, Z., B. Ortega, A. D'Oro, W. Pannell, J. R. Cohen, J. Wang, R. Golish, M. Reed, and J. C. Wang. "Spine Degenerative Conditions and Their Treatments: National Trends in the United States of America." [In eng]. Global Spine J 8, no. 1 (Feb 2018): 57-67.
4 Ibid.
5 Culler, S. D., D. S. Jevsevar, K. G. Shea, K. J. McGuire, M. Schlosser, K. K. Wright, and A. W. Simon. "Incremental Hospital Cost and Length-of-Stay Associated with Treating Adverse Events among Medicare Beneficiaries Undergoing Lumbar Spinal Fusion During Fiscal Year 2013." [In eng]. Spine (Phila Pa 1976) 41, no. 20 (Oct 15 2016): 1613-20.
6 Expected costs refer to costs predicted by the risk adjustment model. For more information on expected costs and risk adjustment, please refer to Section 4.5.
7 For information on how LTC MDS data are used in risk adjustment, please refer to Section 4.5.