Introduction
This document details the methodology for the Low Back Pain measure and should be reviewed along with the Low Back Pain 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, the term “cost” generally means the standardized1 Medicare allowed amount,2 and claims data from Medicare Parts A, B, and D3 are used to construct this episode-based cost measure.
The Low Back Pain episode-based cost measure evaluates a clinician’s or clinician group’s riskadjusted and specialty-adjusted cost to Medicare for patients receiving medical care to manage and treat low back pain. This chronic condition measure includes the costs of services that are clinically related to the attributed clinician’s role in managing care during a Low Back Pain episode.
Measure Rationale
Low back pain is common in the United States, with roughly 20% of Americans experiencing low back pain each year,4,5 and about 6% of Americans requiring ambulatory visits as a result of this condition.6 It is also costly; a 2020 study found that low back and neck pain contributed the most to health care spending among 154 mutually exclusive diagnoses, at $134.5 billion in 2016.7 Trends in data over the past decades indicate gaps in care and opportunities for improvement in treatment. Several studies evaluating data since 1998 indicate large increases resource use for low back pain, despite only modest increases in condition prevalence and little improvement in patient outcomes,8,9,10,11,12 which underscores the need for more precise measures of resource use and quality of care.
Given the prevalence of low back pain in the Medicare population, and the high costs associated with the management of the disease and its complications, the Low Back Pain cost measure represents an opportunity for improvement on overall cost performance.
The Low Back Pain episode-based cost measure was selected for development because of its high impact in terms of patient population, clinician coverage, and Medicare spending, and the opportunity build a complex, yet feasible, chronic condition measure that would address a condition not captured by other cost measures. Following initial feedback gathered during the Wave 4 public comment period,13 the subsequent measure-specific clinician expert workgroup provided extensive, detailed input on this measure.
Measure Numerator
The measure numerator is the weighted average ratio of the winsorized14 scaled standardized observed cost to the scaled expected15 cost for all Low Back Pain episodes attributed to a clinician, where each ratio is weighted by each episode’s number of days assigned to a clinician. This sum is then multiplied by the national average winsorized scaled observed episode cost to generate a dollar figure.
Measure Denominator
The measure denominator is the total number of days from Low Back Pain episodes assigned to the clinician across all patients.
Data Sources
The Low Back Pain measure uses the following data sources:
- Medicare Parts A, B, and D claims data from the Common Working File (CWF)
- Enrollment Database (EDB)
- Long Term Care Minimum Data Set (LTC MDS)16
Care Settings
The Low Back Pain measure focuses on the care provided by clinicians for patients with low back pain. The most frequent settings in which a Low Back Pain episode is triggered include: office, outpatient hospital, and ambulatory surgical center (ASC).
Cohort
The cohort for this cost measure consists of patients who are Medicare beneficiaries enrolled in Medicare fee-for-service that receive care for low back pain.
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 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://www.resdac.org/articles/cms-price-payment-standardizationoverview).
Claim payments from Part D are payment standardized to allow resource use comparisons for providers who prescribe the same drug, even if the drug products are covered under varying Part D plans, produced by different manufacturers, or dispensed by separate pharmacies. For more information, please refer to the “CMS Part D Price (Payment) Standardization” document posted on the CMS Price (Payment) Standardization Overview page. (https://www.resdac.org/articles/cms-price-payment-standardizationoverview).
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 Part D branded drug costs are also adjusted to account for post-point of sale drug rebates; more information can be found in the Methodology for Incorporation of Rebates in Part D Standardized Amounts on the QPP Cost Measure Information "About Cost Measures" page (https://www.cms.gov/medicare/quality-payment-program/cost-measures/about).
4 Will, Joshua Scott, David Bury, and John Miller, “Mechanical Low Back Pain.” American Academy of Family Physicians 98(7) (2018): 421-428.
5 Blanpied et al., “Neck Pain: Revision 2017: Clinical Practice Guidelines Linked to the International Classification of Functioning, Disability and Health From the Orthopaedic Section of the American Physical Therapy Association.” Journal of Orthopaedic & Sports Physical Therapy 47(7) (2017): A1-A83. doi:10.2519/jospt.2017.0302
6 Matthew Davis, “Where the United States Spends its Spine Dollars: Expenditures on different ambulatory services for the management of back and neck conditions.” Spine 37(19) (September 1 2012): doi:10.1097/brs.0B013E3182541F45.
7 Dieleman, Joseph, Jackie Cao, and Abby Chapin, “US Health Care Spending by Payer and Health Condition, 1996-2016.” JAMA Network 323(9) (2020): 863-884. doi:10.1001/jama.2020.0734.
8 Luo, Xuemei, Ricardo Pietrobon, Shawn Sun, Gordon Liu, and Lloyd Hey, “Estimates and Patterns of Direct Health Care Expenditures Among Individuals With Back Pain in the United States.” Spine 29(1) (2004): 79-86. doi:10.1097/01.BRS.0000105527.13866.0.
9 Davis, “Where the United States Spends its Spine Dollars: Expenditures on different ambulatory services for the management of back and neck conditions.”
10 Norman Marcus Pain Institute, “Pain Facts.” Last updated 23 January 2012. https://www.normanmarcuspaininstitute.com/tag/neck-and-shoulder-pain/
11 Ibid.
12 Deyo, Richard, Sohail Mirza, Judith Turner, and Brook Martin, “Overtreating Chronic Back Pain: Time to Back Off?” J Am Board Fam Med 22(1) (2009): 62-68. doi:10.3122/jabfm.2009.01.080102.
13 “Wave 4 Public Comment Summary,” QPP Cost Measure Information, Prior cost measure development and input (https://www.cms.gov/medicare/quality-payment-program/cost-measures/prior).
14 For information on how costs are winsorized, please refer to Section 4.7.
15 Expected costs refer to costs predicted by the risk adjustment model. For more information on expected costs and risk adjustment, please refer to Section 4.7.
16 For information on how LTC MDS data are used in risk adjustment, please refer to Section 4.7.