1     General Considerations

This section describes the implementation of the analysis dataset for QRS instruments as based on the Basic Data Structure (BDS) described in the Analysis Data Model Implementation Guide (ADaMIG). The ADaMIG can be found on the CDISC website at https://www.cdisc.org/standards/foundational/adam. The BDS was chosen as the model for analysis datasets of QRS instruments because it supports a wide variety of analyses, including summaries of total score by timepoint as well as change from baseline by timepoint. This data structure allows the ADaM variables PARAM and PARAMCD to come directly from Study Data Tabulation Model (SDTM) variables RS.RSTEST and RS.RSTESTCD, respectively, for individually captured questions, thus ensuring traceability between SDTM and ADaM data. If other analyses are required that are not supported by the BDS, then consideration would be needed as to the appropriate structure. Analysis requirements always drive the design of the analysis datasets.

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These specific analysis implementation details for the APACHE II are meant to be used in conjunction with ADaMIG. All completed questionnaires, ratings, and scales documentation can be found on the CDISC website at: https://www.cdisc.org/foundational/qrs.

1.1   Representations and Warranties, Limitations of Liability, and Disclaimers

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

CDISC does not endorse any QRS instrument and does not specify how to conduct clinical assessments, protocols, or analyses. CDISC disclaims any liability for your use of this material.

1.2   Copyright Status

CDISC believes this instrument to be in the public domain, but you should perform your own assessment. CDISC has included the APACHE II in the CDISC library of QRS data standards supplements. There may be many versions of this instrument in the public domain or copyrighted. CDISC has chosen to use the version attached to the QRS supplement to the SDTMIG, and the QRS supplement to the ADaMIG is based on the same version.

Note: CDISC Controlled Terminology is maintained by National Cancer Institute (NCI) Enterprise Vocabulary Services (EVS). The most recent versions of the SDTM and ADaM controlled terminologies should be accessed through the CDISC website (https://www.cdisc.org/standards/terminology).

1.3   Known Issues

The Acute Physiology and Chronic Health Evaluation (APACHE II) is a severity of disease measurement and mortality estimation tool for adult subjects applied within 24 hours of admission to an intensive care unit (ICU). The instrument's intended use is for newly admitted subjects to the ICU. The instrument consists of individual items that are summed up to create a total score. This instrument is generally collected once at Screening/Baseline. The total score is normally collected as part of the instrument with no instructions provided for handling missing data. In the majority of cases, where APACHE II is only assessed once and the collected total score used as a baseline covariate, the SDTM RS domain may be sufficient to support the analysis requirements, as a variable in ADSL copied directly from a result/value in SDTM.

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All links are valid and referenced information is current as of the date of this ADaMIG QRS supplement. This supplement does not make recommendations for the handling of missing data or adoption of imputation methods.

3     Scoring Software

There is no known publicly available scoring software as of the date of this ADaMIG QRS supplement.

4     Introduction to the Instrument   

The APACHE II is a severity-of-disease classification system that uses a point score based on the initial values of 12 routine physiologic measurements, age, and previous health status. Scores range from 0 to 71 and higher scores correspond to more severe disease and a higher risk of death. The composite score is based on findings represented in other SDTM domains such as Laboratory Test Results (LB) and Vital Signs (VS).

5     Key Data Checks

The computed total score consists of integer values ranging from 0 to 71. The classification system consists of 11 physiology measures based on a numeric rating scale 0 to 4 where 0 reflects values within the normal range and an increase in the numeric rating scale represents an increase in the abnormality of the physiology measure in either the high or low direction. For Serum Creatinine, the measure is assessed on the same scale but double points assigned for subjects with acute renal failure. The measure evaluating extent of impaired consciousness, is calculated as 15 minus the Glasgow Coma Scale (GCS) Score; so that lower scores indicate mild or no impairment and higher scores represent more severe impairment (possible head and/or central nervous system injury) and range from 0 to 12. Chronological age is divided into age groups which are assigned values of 0, 2, 3, 5, 6. For subjects with a history of severe organ system insufficiency or who are immunocompromised, a numeric rating of 2 or 5 is assigned for chronic health points, where 2 is assigned “for elective postoperative subjects” and 5 is assigned “for nonoperative or emergency postoperative subjects”. For subjects who do not have a history of severe organ system insufficiency or who are not immunocompromised, a NOT DONE record may be retained from the source RS domain with the conditional branching flag (RSCBRFL='Y'). Additionally, a sponsor may choose to set AVAL=0 for subjects who are 'healthy' or do not meet the criteria for assigning chronic health points. This decision must be clearly documented as the analysis value of 0 is logically derived or implied.

6     Example

6.1   Background

Analyses based on ADaM datasets may vary depending on the sponsor, therapeutic area, and the needs of regulatory authorities in their decision-making processes. This fictional example is provided for illustrative purposes only. The ADaM dataset describing the analysis results from an instrument is based on the protocol and statistical analysis plan (SAP) for the individual study.

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In the example presented here, it is assumed that the final APACHE II analysis dataset (ADAPCH) contains all of the original records, plus a record for the computed total acute physiology score and a record for the computed total APACHE II for each subject and assessment timepoint. The date of the assessment—and time of the assessment, if collected—should also be included in the dataset. For traceability, raw item-level responses from the SDTM RS.RSORRES variable, stored separately from the analysis variable AVAL, are included. Derivation type (DTYPE) should be used to clearly indicate records where missing values have been imputed using sponsor-defined imputation methods. If useful for analysis, a summary analysis dataset which includes only the computed total score records may also be created.

6.2   Example Analysis Dataset, Variable and Value-level Metadata

The ADAPCH Dataset Metadata table shows an example of how the APACHE II may be implemented in ADaM. The dataset metadata is a recommendation for the dataset name, label, structure, and keys. These can be modified for sponsor-specific standards and analyses. 

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6.3   Example Analysis Dataset 

The APACHE II Analysis Dataset tables below show the terminology and variables for implementing the example analysis dataset for this instrument in the BDS. This specific example is taken from a Phase II, randomized, controlled, open label multi-center study to assess the efficacy and safety of Drug A for the treatment of SARS-CoV-2 infected subjects with COVID-19 pneumonia and impaired respiratory function. The primary outcome measure is APACHE II Severity of Disease Score on Day 15 or on the Day of Discharge (Whichever is Earlier). This measure compares Drug A + Standard of Care (SOC) versus the Standard of Care (SOC). 

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