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Thursday, July 9, 2015

Criticality vs. Severity in Allergies in HL7 CCDA

The HL7 Structured Documents workgroup had on its agenda to discuss updates to C-CDA 1.1 and 2.1 to address Allergy Criticality and Severity.  I first mentioned this problem at the end of last month.

Today, we discussed this in committee and with John Quinn, the HL7 CTO (who must approve errata), and agreed to address this issue as errata in the CCDA 2.1 DSTU Update project.  Once again, HL7 has shown that they can be responsive in addressing a critical issue.  I'm pleased to see this, and can only hope that we don't wind up being so responsive that we need to institute  Bureau of Sabotage.

Effectively what we will be doing in CCDA 2.1 DSTU Update project is create a new template to support criticality, and deprecating use of Severity template on the allergy itself.

   -- Keith

For those who aren't familiar with the issue, I will reproduce the important content below:

The stated project need for SDWG project 1014 is “Proposed US federal regulation has identified C-CDA 2.0 as being the preferred way forward, but introduces a need for compatibility that was not anticipated for in the original project scope.  An update is needed to ensure that new templates are backwards compatible.

Existing Consolidated CDA (C-CDA) needs to be enhanced by adding templates to represent priority data elements, and modified/new section level and document level templates needed for transitions of care and care plans, areas essential to patient care and the meaningful use of EHRs; we need to incorporate errata; and we want to address areas that implementers have found to be ambiguous.”    Patient Care is a co-sponsor of this project originally approved in 2013.  The TSC approved the updated project scope statement on June 9, 2015. 

The Patient Care Work Group (PCWG) has been working on the Allergy and Intolerance topic to update and harmonize standards since 2010.  The products related to this work include an Allergy and Intolerance Domain Analysis Model, Allergy and Intolerance Clinical Models (DSTU) and an Allergy and Intolerance FHIR resource.  In order to ensure harmonization across HL7 standards, the Patient Care WG conducted an extensive review of C-CDA R1.1 and R2.0.  During this review, the PCWG presented on-going issues to the SDWG at two face-to-face sessions (most recently at the Paris WG meeting) in order to reinforce the findings and recommendations of this year-long analysis of known C-CDA issues.  The results of this analysis were posted as DSTU comments for C-CDA R1.0 (Comment 643) and C-CDA R2.0 (Comment 644).   At the request of the SDWG, multiple comments were submitted against each C-CDA version in tabular format.  This summary document can also be found on the Patient Care wiki: C-CDA Harmonization Table.

The Issue

Patient Care has kept the SDWG apprised of work in the area of Allergies and Intolerances since this work began in 2010.  Multiple presentations on this topic were given at each Work Group meeting (see minutes from each joint PCWG/SDWG Thursday Q2).  As the PC WG harmonization process continued, it was apparent that the C-CDA did not recognize some of the concepts within the PCWG DAM or clinical models, or the FHIR allergy and intolerance resource.  Working with a primary representative and additional representatives from the SDWG, the PCWG has diligently outlined and proposed solutions to ensure harmonization all of the HL7 products that address allergies and intolerances.  This has included extensive terminology work in coding systems including HL7, SNOMED CT and LOINC. 

Extensive comments and recommendations were posted to the DSTU website for both C-CDA R1.1 and R2.0, with the expectation that these comments would be duly considered during the current review of errata and backwards compatibility issues.  Comments from the PCWG are substantive and seek to ensure that the use of C-CDA provides clinically correct data exchange between providers. 

On Thursday, June 25, the Patient Care WG presented a synthesis of these comments to the SDWG.  The most significant issue at hand relates to the use of the Severity Template in two contexts related to the Allergy and Intolerance Observation and the Reaction Observation. 

The current relationship of the Severity Template is shown in this diagram taken from C-CDA R1.1.  This relationship is retained in R2.0:  The relationship between the allergy observation and severity is erroneous, is creating confusion through ambiguity and does not reflect the current relationships in other HL7 allergy and intolerance standards.

The PCWG Allergy and Intolerance DAM and Clinical Models as well as the FHIR resource have a different relationship. 

A reaction is correctly described by severity, e.g. a patient had a mild reaction to a drug, or a severe reaction to a food.  However, the allergic condition is not described in terms of severity, rather the term criticality.  The concept of criticality is in the RIM as the code “CRIT”[1] in ActCode/ObservationType, and is associated with the allergic or intolerant condition. 

The definition of criticality as per the PCWG is as follows:  A clinical judgment as to the worst case result of a future exposure (including substance administration). When the worst case result is assessed to have a life-threatening or organ system threatening potential, it is considered to be of high criticality.

It is important to note that there is not a 1:1 relationship between the severity of a reaction and the criticality of the condition.  For example a patient might have a severe reaction to a medication (nausea) however that condition has a low criticality – e.g. the medication can still be prescribed if medically indicated.  Conversely, a child may have a mild reaction on the first exposure to a peanut, however a repeat exposure to peanuts may be life threatening and therefore of high criticality.

After the presentation by the PCWG on June 25 to the SDWG, the group discussed the issues at hand for some 30 minutes.  Despite an acknowledgement of the issues, no resolution was proposed nor voted on by the SDWG. 

Patient Safety and Clinical Practice

The PCWG has many other DSTU comments – however, we are writing to ensure that the criticality concept is included without delay in the C-CDA templates. 

Currently the use of severity in the context of a reaction and also in the context of a condition has the following potential consequences in systems exchanging information on allergies and intolerances:

1.      Patient safety issue:  When a system reports an allergic or intolerant reaction with mild severity but which is associated with a condition of high criticality (e.g. the risk of a life threatening reaction), based on severity alone a receiving system could allow an order to be processed for a drug or medication that should not be prescribed.  The current construct in the C-CDA does not capture or convey the correct information to mitigate this risk.
2.      The current construct does not allow for the most effective treatment:  A patient may report a severe reaction to a medication, such as “severe nausea” – however, nausea in most cases is of low criticality. A similar example is the common reaction to epinephrine (adrenaline) where most patients would describe their nausea, vomiting and sweating as severe – but if adrenaline is clinically indicated, it will be prescribed.   The current C-CDA construct is unable to correctly convey this information.
3.      Alert fatigue:  Clinicians often complain of alert fatigue, including for alerts for the severity of an allergic condition, since it is a spurious concept.  Given the documented drug-allergy alert override rate of around 90%[2], the use of criticality will clearly convey issues that require a careful consideration of the clinical options. 

In addition to the DSTU comments prepared by the PCWG, the C-CDA R2 ballot comments included a comment on the use of severity in two contexts.  The reconciliation spreadsheet for the 2013 ballot (Comment 290) noted under the disposition that SDWG would consult with the Allergy and Intolerance DAM.  However the final disposition reads as follows:   "In CCD.xml, add commenting [sic] which relates to the description in the severity template: ""When the Severity Observation is associated directly with an allergy it characterizes the allergy. When the Severity Observation is associated with a Reaction Observation it characterizes a Reaction."  This statement is incorrect, and it is unfortunate that the use of criticality (a concept currently existing in the RIM) was not considered. 

The C-CDA R2.1 Project

SDWG is considering candidate errata for C-CDA 2.1, a project designed to ensure backwards compatibility from R2.0 to R1.1 based on considerations related to the Meaningful Use 3 NPRM.  The project wiki is here: and the need for the project opinion is here:

What are errata?

The SDWG has discussed what errata are: (the post is the opinion of the author)

The Chicago Manual of Style defines errata as follows: "Errata, lists of errors and their corrections, may take the form of loose, inserted sheets or bound-in pages. An errata sheet is definitely not a usual part of a book. It should never be supplied to correct simple typographical errors (which may be rectified in a later printing) or to insert additions to, or revisions of, the printed text (which should wait for the next edition of the book). It is a device to be used only in extreme cases where errors severe enough to cause misunderstanding are detected too late to correct in the normal way but before the finished (book) is distributed. Then the errors may be listed with their locations and their corrections on a sheet that is tipped in, either before or after the book is bound, or laid in loose, usually inside the front cover of the book.
Reference:  Chicago Manual of Style:  (referenced June 28, 2015)

Is the issue of criticality an erratum?  The PCWG feels that the omission of the criticality concept is of sufficient gravity to qualify as an erratum that must be considered in the current C-CDA 2.1 process.  The risk of not dealing with the criticality issue at this time is that the Meaningful Use 3 standard will point to a version of the C-CDA that is clinically incorrect and has the potential to cause patient harm. 

The PCWG understands the alacrity with which the errata process must occur to meet federal timelines.  The current timeline for C-CDA DSTU errata review is due to begin on July 1 and end on July 10th, 2015.  While the HL7 Governance and Operations Manual describes the process for submission of DSTU errata to the HL7 CTO, the PCWG appeals to the HL7 SDWG to duly consider this request prior to finalizing C-CDA 2.1 comments through the DSTU errata process.  Normally such an activity would be balloted allowing for broad member comment. 

Outcome Requested

The C-CDA is cited as the means to support health information exchange within the NPRM[3] for MU 3.    HL7 needs to ensure that the information exchanged is correct, based on current standards such as the RIM, and responsibly mitigates the risk of ambiguous and clinically incorrect information. The Patient Care WG respectfully requests that the concept of criticality be added to the C-CDA standard as an erratum because of the risk of patient harm. 

While the addition of a criticality template to C-CDA would be the most complete solution to this issue, there are several other paths forward:
1. At a minimum: Change the incorrectly referenced severity template to SHOULD NOT at the Allergy Intolerance Observation level.
2. If possible: Add a MAY conformance to the Allergy Intolerance Observation that permits use of the Criticality Observation.

The PCWG stands ready to assist with this endeavor. 

Respectfully submitted by the Patient Care WG Allergy and Intolerance Project Team,

[1] The current RIM definition of criticality is: CRIT (criticality) An observation representing a clinical judgment as to the worst case result of a future occurrence or the evolution of a current occurrence. It would be based on the severity of past occurrences, the details of what produced the past occurrences and the life-threatening or organ system threatening potential of the observation type.  The PCWG has a harmonization request pending to update this definition. 
[2] Bryant, AD, Fletcher, GS, Payne, TH.  Drug Interaction override rates in the Meaningful Use era – no evidence of progress.  App Clin Infor 2014:5(3);802-813


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