CDISC ADaM Phases, Periods, and Subperiods: A Case Study

Abstract

INTRODUCTION Many clinical studies are comprised simply of Screening, Treatment, and Follow-up time periods. Occasionally the Treatment portion of the study needs to be divided further into analysis periods, and even sub-levels within one or more of the analysis periods, which introduces another layer of complexity when creating CDISC Analysis Data Model (ADaM) data sets. If it is important, for example, to know additional study details when a particular adverse event started, then the ADaM permissible Phase, Period, and Subperiod variables should be utilized.OBJECTIVES This paper will present a case study on an actual clinical trial that had interesting challenges regarding the correct implementation of the ADaM guidelines for these variables. In this study the route of administration was being investigated.  Rather than comparing study drugs, the route changed for each subject from one set of visits to the next.METHODS Topics will include: key ADaM variables that come into play, ADSL variables and how they relate to other ADaM Basic Data Structure (BDS) domain variables, and sample SAS macro code to derive some of the key treatment and timing variables. RESULTS Example data from the case study is displayed to illustrate the proper way to utilize the full set of Phase, Period, and Subperiod variables.  ADSL data is shared, as well as ADVS (vital signs) as an example of a BDS data set.  Additional tips are offered with regard to the Screening Phase, screen failures, tying treatment variables to the Period variables, and challenges when date or time information was not collected.CONCLUSIONS A complicated study design means multiple challenges in adhering to CDISC requirements, especially ADaM data sets.  But with a well thought out plan, and use of the ADaM Implementation Guide to tackle the obstacles piece by piece, the puzzle can come together in the end.