Dear CFAST:  Please Slow Down to Catch Up

A new year and many new things to think about in the greater world of research and healthcare, though there are still plenty of unfinished thoughts about CDISC to expound upon.  In my last post, I tried to sum up my thoughts on SDTM, advocating a more restrained approach that prioritized stability of the core SDTM/SDTMIG standard over frequent change, and proposing a cookbook recipe approach to addressing gaps in the model, especially for the CFAST Therapeutic Area User Guides (TAUGs).

And today, I’d like to echo the slow food movement, with a plea directly to CFAST to also take a breather and slow down. This may seem like a departure from my past point of view – I was a strong advocate of adopting Scrum for standards in order to get more things done. But moving ahead more rapidly should not be done at the expense of consistency and clarity of approach.   CFAST TAUGs have been produced at a relatively prolific rate of 6 or more per year since 2013.  Yet the pressure during that span has been to issue even more TAUGs each year, rather than maintaining consistency in the modeling approaches used by them all.

So, as former Chair of the CFAST TA Steering Committee, I’d like to respectfully suggest that they apply the brakes for a bit until they can go back and bring the full body of published TAUGs to a common parity by fixing the inconsistencies that currently exist.

This is the long-standing “maintenance issue” that was never completely addressed during my term as Chair.  There are several cases where modeling approaches adopted in one TAUG changed when a new TAUG was issued, which might not be apparent to those who don’t read every separate publication.  These inconsistencies in approach work against the goals of standardization, and can only aggravate the types of variances between submissions that have often frustrated FDA reviewers with SDTM submissions to date.  Now’s the time to go back and fix these dangling loose ends, since the FDA has yet to issue a clear message endorsing TAUGs, and since many sponsors are still evaluating how to utilize them.

To take one prominent example, there have been at least four different approaches to represent the diagnosis date of the condition or disease under study in TAUGs over the years:

  1. Putting the date of diagnosis in q Medical History (MH) domain record, using MHCAT = ‘PRIMARY DIAGNOSIS’ and MHSCAT to distinguish between an onset course and a current course (though these important categorization values are not specified as controlled terminology). This approach was used in the Alzheimer’s, Parkinson’s and other TAUGs.
  2. Creating a Findings About (FA) record, with the FAOBJ = <disease or condition>, and the date as an observation result. This approach was used in the Asthma TAUG.
  3. Creating a supplemental qualifier record with QNAM=’MHDXDTC’, an approach that was used in the Diabetes TAUG.
  4. Creating a new MH record using the new SDTM v1.5 variable MHEVTTYP = ’DIAGNOSIS’ – which was an approach recommended by the SDS Leadership group (including me) in 2014 and was adopted as the preferred approach in some of the more recent TAUGs (e.g., MS). Unfortunately, adoption of this approach has not been embraced by the full SDS team and is limited because it’s not included in the SDTMIG and requires a new variable which is not in the currently accepted v1.4 SDTM.

Now, given that the date of diagnosis is likely to be of interest to all medical reviewers, the notion of how to represent a date of diagnosis of the disease under study consistently should be tackled independently of any TA.  And the correct approach should be easy to find by implementers.  But, currently, the method may vary depending on what document each implementer uses as a guideline.

One way for dealing with this type of maintenance issue is to remove it from the individual TAUGs and making it a standardized convention that could be consulted by any implementer as a separate resource.  Using my cookbook recipe approach, such a guideline might say:

  • Always represent Diagnosis Date as an MH event record
  • Use MHEVTTYP to distinguish it from other elements of history with controlled terminology value = ‘DIAGNOSIS’.
  • If using SDTM v1.4 or earlier, represent MHEVTTYP (with controlled terminology QNAM value of ‘MHEVTTYP’ and QVAL = ‘DIAGNOSIS’.

Now (especially if supplemental qualifiers are represented within the parent domain where they belong) wouldn’t that be easier on the FDA reviewer?  Wouldn’t it be helpful to always know where to find such an important bit of data no matter who submits it irrespective of which reference (IG, UG) an individual sponsor employee may have chosen to follow at the time?  I mean, can CDISC and CFAST really say they has an effective standard if they’re not consistent on such points?

So, one more shout in the dark:

  • Let’s ease the constant pressure to create new TAUGs, domain models and new IG versions (which often seem like they’ll never be finished anyway)
  • Stop creating new TAUGs that contradict modeling approaches of older ones until all the published ones can be made consistent to a common baseline. One way to do this would be to remove all references how to represent certain modeling use cases like Diagnosis Date from the published TAUGs and replace with a link to a document showing a preferred standard approach (though an example might still be provided in the TAUG).
  • Start representing more recipes and examples for other preferred modeling conventions with better engagement of the CDISC standards implementer community as an interactive forum.
  • Make a firm decision once and for all between “Taste Great” and “Less Filling” as key modeling principles moving forward.

If you’d like to learn more about some of the significant variations across the CFAST TAUGs, please refer to this excellent paper by Johannes Ulander and Niels Both presented at PhUSE 2015.


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