Introduction
This document details the methodology for the Chronic Kidney Disease (CKD) measure and should be reviewed along with the CKD 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 CKD episode-based cost measure evaluates a clinician’s or clinician group’s risk-adjusted and specialty-adjusted cost to Medicare for patients who receive medical care to manage and treat stage 4 or 5 chronic kidney disease. This chronic condition measure includes the costs of services that are clinically related to the attributed clinician’s role in managing care during a CKD episode.
Measure Rationale
Chronic kidney disease (CKD) is a highly prevalent condition. Approximately 38% of US adults over the age of 65 are estimated to have CKD.4 Medicare spending for patients with CKD was more than $85 billion in 2020, 5 with a large component of costs coming from re-hospitalizations.6 While patients with diagnosed CKD make up 14% of the 65 and older Medicare population, they contribute 25% of total Medicare expenditures.7 In 2020, annual costs for patients older than 65 with CKD were approximately double those for patients without CKD. 8 Common complications including hospitalizations, readmissions, and mortality are costly to Medicare.9,10,11
Performance gaps in treating this population include suboptimal management of the complications related to CKD, comorbid conditions such as diabetes and heart disease,12 and the transition from CKD to end-stage renal disease (ESRD). Early detection and access to nephrology care has been linked to better patient outcomes and cost savings, with studies indicating that patients with early referral had slower rates of CKD progression, lower use of inpatient services, and fewer reported complications compared to patients with late referrals.13 CKD is a highly prevalent condition in the Medicare population and is associated with high costs for the management of the disease and its complications. As such, a cost measure represents an important opportunity for improvement on overall cost performance.
The CKD episode-based cost measure was selected for development because of its high impact in terms of patient population, clinician coverage, and Medicare spending, and assesses costs for a condition not captured by other cost measures. This CKD measure was also developed in consideration of alignment opportunities, particularly the Kidney Care First (KCF) Option of the Kidney Care Choices (KCC) Advanced Alternative Payment Model, and its CKD cost measure.14 A measure-specific clinician expert measure development workgroup was convened to provide extensive, detailed input on this measure.
Measure Numerator
The measure numerator is the weighted average ratio of the winsorized15 scaled standardized observed cost to the scaled expected16 cost for all CKD 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 CKD episodes assigned to the clinician across all patients.
Data Sources
The CKD measure uses the following data sources:
- Medicare Part A, B, and D claims data from the Common Working File (CWF)
- Enrollment Database (EDB)
- Long Term Care Minimum Data Set (LTC MDS)17
Care Settings
The CKD measure focuses on the care provided by clinicians practicing in non-inpatient hospital settings for patients with CKD. The most frequent settings in which a CKD episode is triggered include: office, outpatient hospital, and skilled nursing facility (SNF).
Cohort
The cohort for this cost measure consists of patients who are Medicare beneficiaries enrolled in Medicare fee-for-service who receive medical care to manage and treat stage 4 or 5 chronic kidney disease.
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 Rebates in Part D Standardized Amounts on the CMS.gov QPP Cost Measures Information Page’s About Cost Measures page (https://www.cms.gov/medicare/quality-payment-program/cost-measures/about).
4 CDC, Chronic Kidney Disease in the United States 2021, https://www.cdc.gov/kidneydisease/publications-resources/ckd-national-facts.html
5 “US Renal Data System 2022 Annual Data Report: Healthcare Expenditures for Persons with CKD.” United States Renal Data System, (2022): Chapter 6. https://usrds-adr.niddk.nih.gov/2022/chronickidney-disease/6-healthcare-expenditures-for-persons-with-ckd
6 Golestaneh L, Alvarez PJ, Reaven NL, Funk SE, McGaughey KJ, Romero A, Brenner MS, Onuigbo M., “All-cause Costs Increase Exponentially with Increased Chronic Kidney Disease Stage.” The American Journal of Managed Care 23, no. 10 (2017): S163-S172.
7 “US Renal Data System 2022 Annual Data Report: Healthcare Expenditures for Persons with CKD.” United States Renal Data System, (2022): Chapter 6. https://usrds-adr.niddk.nih.gov/2022/chronickidney-disease/6-healthcare-expenditures-for-persons-with-ckd
8 Ibid.
9 Webster AC, Nagler EV, Morton RL, Masson P. “Chronic Kidney Disease,” The Lancet, Vol 389, 10075 (2016): 1238-1252. https://doi.org/10.1016/S0140-6736(16)32064-5.
10Bansal N, Zelnick L, Bhat Z, Dobre M, He J, Lash J, Jaar B, Mehta R, Raj D, Rincon-Choles H, Saunders M, Schrauben S, Weir M, Wright J, Go AS; CRIC Study Investigators. “Burden and Outcomes of Heart Failure Hospitalizations in Adults with Chronic Kidney Disease,” J Am Coll Cardiol, no. 73, 21 (2019):2691-2700. doi: 10.1016/j.jacc.2019.02.071. 2691-2700.
11Hakopian NN, Gharibian D, Nashed MM. “Prognostic Impact of Chronic Kidney Disease in Patients with Heart Failure,” The Permanente Journal, 23 (2019): 18-273.
12CDC, Chronic Kidney Disease in the United States 2021, CKD Related Health Problems, https://www.cdc.gov/kidneydisease/publications-resources/annual-report/ckd-related-healthproblems.html
13Liu, Harry H., and Sophia Zhao. "Savings opportunity from improved CKD care management." Journal of the American Society of Nephrology 29, no. 11 (2018): 2612-2615.
14CMS, “Kidney Care Choices (KCC) Model,” https://innovation.cms.gov/innovation-models/kidney-carechoices-kcc-model
15For information on how costs are winsorized, please refer to Section 4.7.
16Expected 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.
17For information on how LTC MDS data are used in risk adjustment, please refer to Section 4.7.