This document details the methodology for the Renal or Ureteral Stone Surgical Treatment measure and should be reviewed along with the Renal or Ureteral Stone Surgical Treatment Measure Codes List file, which contains the medical codes used in constructing the measure.
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 Renal or Ureteral Stone Surgical Treatment episode-based cost measure evaluates a clinician’s risk-adjusted cost to Medicare for patients who receive surgical treatment for renal or ureteral stones 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 90 days prior to the clinical event that opens, or “triggers,” the episode through 30 days after the trigger.
In 2013, 23,000 Medicare patients were hospitalized with a primary diagnosis of kidney stones, and approximately 1.1 million patients with a primary diagnosis of kidney stones received ambulatory and outpatient (OP) evaluation and management care.3 It is estimated that the total expenditure among Medicare patients 65 and older for treatment of urinary tract stones exceeds $1 billion each year.4 The Renal or Ureteral Stone Surgical Treatment episode-based cost measure was selected for development based on input from an expert clinician committee—the Urologic Disease Management 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.
The cost measure numerator is the sum of the ratio of observed to expected5 payment-standardized cost to Medicare for all Renal or Ureteral Stone Surgical Treatment episodes attributed to a clinician. This sum is then multiplied by the national average observed episode cost to generate a dollar figure.
The cost measure denominator is the total number of episodes from the Renal or Ureteral Stone Surgical Treatment episode group attributed to a clinician.
The Renal or Ureteral Stone Surgical Treatment 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)6
Methodologically, the Renal or Ureteral Stone Surgical Treatment cost measure can be triggered based on claims data from: acute inpatient (IP) hospitals, hospital outpatient departments (HOPD), ambulatory/office-based care centers, and ambulatory surgical centers (ASC).
The cohort for this cost measure consists of patients who are Medicare beneficiaries enrolled in Medicare fee-for-service and who receive surgical treatment for renal or ureteral stones that triggers a Renal or Ureteral Stone Surgical Treatment 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).
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 “Urologic Diseases in America. Kidney Stones.” National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2017.
4 Table 14-46. Economic Impact of Urologic Disease. In: Chapter 14. Litwin MS, Saigal CS, editors. Urologic Diseases in America. US Department of Health and Human Services, Public Health Service, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases. Washington, DC: US Government Printing Office, 2012; NIH Publication No. 12-7865 pp. 486.
5 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.
6 For information on how LTC MDS data are used in risk adjustment, please refer to Section 4.5.