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© 2022 Clinical Data Interchange Standards Consortium, Inc. All rights reserved. 

1 Introduction

This document describes the CDISC implementation of the Psoriasis Area and Severity Index Version EMA (PASI EMA) instrument. 

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The CDISC Intellectual Property Policy can be found on the CDISC website at: https://www.cdisc.org/about/bylaws.

1.1 Representations and Warranties, Limitations of Liability, and Disclaimers

This document is a supplement to the SDTMIG for Human Clinical Trials and is covered under Appendix F of that document, which describes representations, warranties, limitations of liability, and disclaimers. Please see Appendix F of the SDTMIG for a complete version of this material.

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Although the United States Food and Drug Administration (US FDA) has provided input with regard to this supplement, this input does not constitute US FDA endorsement of any particular instrument.

2 Copyright Status

CDISC believes this instrument to be in the public domain, but you should perform your own assessment. CDISC has included the PASI EMA in the CDISC library of QRS data standards supplements. Hence, CDISC developed RSTESTCD and RSTEST for each item based on the actual text on the instrument. There may be many versions of this instrument. CDISC has chosen to use this version as the data standard.

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• European Medical Agency Committee for Medicinal Products for Human Use (CHMP). Guideline on Clinical Investigation of Medicinal Products Indicated for the Treatment of Psoriasis. Published November 18, 2004. [Accessed June 15, 2022]. Available at: https://www.ema.europa.eu/en/clinical-investigation-medicinal-products-indicated-treatment-psoriasis.
• CDISC believes this instrument to be in the public domain, but you should perform your own assessment.

3 The RS Domain Model

3.1 Assumptions for the RS Domain Model

All assumptions and business rules described in the SDTMIG RS domain are applicable to this supplement. Additional assumptions specific to the PASI EMA are listed below.

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1. The scale points for the symptoms include a numeric rating (0-4) and a definition of what is represented by the rating (e.g., 0 = "No symptoms"). For the PASI EMA, RSORRES is populated with the text description; the numeric rating is represented in the standardized character and numeric result variables RSSTRESC and RSSTRESN.

   1. CDISC created a CRF based on the EMA guidelines using the symptom terms "erythema/redness," "thickness/induration," and "desquamation/scaling." Per subject-matter expert recommendations, these terms were included even though not all of them were referenced in the EMA article.
      
2. The scale points for the area include a numeric rating (1-6) and a definition of what is represented by the rating (e.g., 1 = "<10%"). For the area, RSORRES is populated with the text description; the numeric rating is represented in the standardized character and numeric result variables RSSTRESC and RSSTRESN.
   

3. The PASI EMA instrument includes subscores and a total score that are considered as captured data on the CRF and are not considered as derived in the example below. These scores may be submitted in SDTM or derived in the Analysis Data Model (ADaM) per scoring instructions from the EMA reference.

   1. If operationally defined by the sponsor, it is the sponsor's responsibility to set the --DRVFL flag based on their eCRF process to derive subtotals and total scores. An investigator-derived score will be considered a captured score and not flagged. When subtotal and total scores are derived by the sponsor, the derived flag (--DRVFL) is set to "Y". However, when the subtotal and total scores are received from a central provider or vendor, the value would go into --ORRES and --DRVFL would be null (see SDTMIG Section 4.1.8.1, Origin Metadata for Variables).

   2. If scores are received by the sponsor, it is recommended that they are submitted to SDTM and verified in ADaM.

4. Records are created in rs.xpt for every item on the instrument: 

   1. For items with no data, RSORRES, RSSTRESC, and RSSTRESN are all missing and RSSTAT = "NOT DONE".  If the reason is known, that reason is represented in RSREASND (e.g., RSREASND = "REFUSED"). If the reason is unknown, RSSTAT = "NOT DONE" and RSREASND is missing.

5. Terminology

   1. RSCAT, RSTESTCD, and RSTEST values are included in CDISC Controlled Terminology.

   2. A full list of value sets for the result field is provided in Section 4, SDTM Mapping Strategy.

3.2 Example for the PASI EMA RS Domain Model

The PASI EMA example below shows the terminology used to implement the instrument in the RS domain. The example uses CDISC Controlled Terminology for RSTESTCD, RSTEST, and RSCAT. All original results, matching the CRF item response text, are represented in RSORRES. This result is then represented as a standard numeric score in RSSTRESN and as a standard character representation in RSSTRESC.

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4 SDTM Mapping Strategy

This section is used for reference regarding the CRF data capture and to understand the alignment of the instrument to the SDTM RS domain. It also provides guidance on how the result variables (RSORRES, RSSTRESC, and RSSTRESN) should be populated.

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