DOI: 10.7910/dvn/syjim7
title: CCW Chronic Conditions

description: &lt;section&gt;
&lt;p&gt;
 &lt;h4&gt;&lt;strong&gt;CCW Chronic Condition Segments&lt;/strong&gt;&lt;/h4&gt;
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&lt;h5&gt;&lt;strong&gt;Overview&lt;/strong&gt;&lt;/h5&gt;
 &lt;p&gt;
 CCW Chronic Condition Segments can be requested in addition to the Master Beneficiary Summary File (MBSF) base file. These segments provide standardized indicators of whether a beneficiary has specific chronic conditions, derived from Medicare claims data using CMS algorithms.
 &lt;/p&gt;

 &lt;p&gt;
Each record in the Chronic Condition segment links to the beneficiary in the MBSF base file through BENE_ID, allowing researchers to combine chronic condition flags with demographics, enrollment, and mortality data.
&lt;/p&gt;

&lt;h5&gt;&lt;strong&gt;Purpose and Methodology&lt;/strong&gt;&lt;/h5&gt;
&lt;p&gt;
The CCW chronic condition indicators were created to simplify research by applying validated claims-based algorithms to identify common chronic diseases, removing the need for researchers to define their own coding logic. These algorithms scan inpatient, outpatient, carrier, and other claims files over a defined lookback period of one to three years, depending on the condition. To ensure reliability, beneficiaries must also have sufficient fee-for-service (FFS) coverage to capture all relevant claims; those enrolled in managed care (MA/HMO) plans often lack complete claims data.
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&lt;h5&gt;&lt;strong&gt;Versions Available&lt;/strong&gt;&lt;/h5&gt;
&lt;p&gt;
The Chronic Conditions Data Warehouse (CCW) provides two versions of standardized chronic condition indicators:
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 &lt;h4&gt;&lt;strong&gt;&lt;a href="https://www2.ccwdata.org/web/guest/condition-categories-chronic#cc27" target="_blank"&gt;1. 27 CCW Chronic Conditions&lt;/a&gt;&lt;/strong&gt;&lt;/h4&gt;
 &lt;p&gt;
 Developed by CMS using algorithms based on validated research literature and federal guidelines. These indicators identify the presence of chronic conditions using Medicare claims data over a defined lookback period. Uses both ICD-9-CM and ICD-10-CM diagnosis codes, depending on the year.
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 &lt;ul&gt;
 &lt;li&gt;&lt;strong&gt;CMS Coverage:&lt;/strong&gt; 1999–2021&lt;/li&gt;
 &lt;/ul&gt;

 &lt;h4&gt;&lt;strong&gt;&lt;a href="https://www2.ccwdata.org/web/guest/condition-categories-chronic#cc30" target="_blank"&gt;2. 30 CCW Chronic Conditions&lt;/a&gt;&lt;/strong&gt;&lt;/h4&gt;
 &lt;p&gt;
 In 2020, CMS collaborated with an expert panel to refine and enhance the original 27-condition algorithms. This led to the expanded and improved 30 CCW Chronic Conditions, which reflect updated clinical standards, enhanced claims logic, and improved identification accuracy. Algorithms are based entirely on ICD-10-CM diagnosis codes (no ICD-9).
 &lt;/p&gt;
 &lt;ul&gt;
 &lt;li&gt;&lt;strong&gt;CMS Coverage:&lt;/strong&gt; 2017-present&lt;/li&gt;
 &lt;/ul&gt;

 &lt;h4&gt;&lt;strong&gt;Access and Usage&lt;/strong&gt;&lt;/h4&gt;
 &lt;p&gt;
 These datasets are restricted-use due to the inclusion of sensitive and identifiable health information. As such, the data files themselves cannot be shared via this Dataverse entry.
 &lt;/p&gt;
 &lt;p&gt;
 Students, post-docs, and researchers conducting NSAPH-related research in collaboration with PIs at Harvard or affiliated institutions may gain access to the data, provided they have submitted a project initiation form, are listed on an approved IRB protocol, and have completed all required data security trainings.
 &lt;/p&gt;

 &lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; No data files are included in this entry. This documentation serves as a reference to the raw, unprocessed data files received from CMS.&lt;/p&gt;
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