Allergy & Intolerance Drug Sub-project

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Purpose

Produce a list of unique substances and multiple substance medications used in allergy & intolerance lists, ordered by frequency of incidence. This list will support the use of common elements for data capture and validation of data exchange. This list is not intended to prevent the recording of unusual substances where necessary, whether by code or text.

We would like to provide a set of standard coded identifiers for these substances. The codes for such a list would need to be free, readily available, and accepted for use by international stakeholders.

Note that the criterion is clinical use, not chemical specificity. I.e., if all we know is that the patient reports an allergy to "fish," that's what we can record. Similarly, if a patient has a reaction to percocet, and the clinician doesn't have evidence that supports identification of a specific ingredient, then "percocet" is what we know.

Goal

• A list of substances ordered by frequency of incidence, with frequency ratios
• Identifiers for these substances, using freely available standard identifiers

Plan

• Confirm goals
• Assess assets
• Evaluate gaps
• Fill gaps

Open questions

1. Negatives
   1. NKA, NKDA, NKFA. Do we need NKEA, NKFDA?
2. Scope
   1. How do we identify biologics, vaccine components
   2. How do we identify herbals, supplements
   3. How do we identify environmentals
   4. How do we identify supply items (latex, adhesive)
3. What system(s) should be used for encoding?
   1. Assumption: do we need to choose, or can we provide a list of substances with all pertinent code assignments?
   2. Criteria
      1. Maximal coverage of identified requirements
      2. Ability to add missing items
      3. Freely available
      4. International
   3. Candidates
      1. SNOMED CT: substances, classes; mixtures only as products. Licensing issue.
      2. RxNorm: substances & mixtures. No license issue, but US realm.
      3. NDF-RT: classes only. Class definitions problematic.
      4. UNII: substances only. US realm. no relationships (e.g., of salts)
      5. ATC: classes only. Class definitions problematic.
      6. INN: no access to list; tbd
      7. Proposal to use whatever G-SRS chooses to use. Will evaluate when available.
4. list stewardship & maintenance responsibility
5. harmonizing thresholds for drugs & food
6. single mapping per code or multiple table
7. single value set or multiple
8. How to present guidance
   1. false categories
   2. distinguishing allergies from side effects (e.g., denying zith due to erith sensitivity)
   3. criticality

Specific Questions

1. Iodinated contrast media
   1. Use "high osmolality contrast media"?
2. Penicillins
   1. Can we identify truly cross-reactive subgroups?
3. Morphine derivatives. Morphine and related. List as Morphine and let drug check worry about x-reactivity?
4. Beta Lactamase Inhibitors.
5. Salicylates. A class? Infer topical salicylates? Include ASA?
   1. ASA (salicylates)
6. influenza virus vaccine, inactivated. Etc. CVX seems too specific, but no general terms available for components.
7. narcotic analgesics. Opioids?
8. Estrogens. Class or IN.
9. ASPIRIN BUFFERED.
10. Tetanus. tetanus toxoid vaccine, inactivated?
11. Nitrates, Organic
12. Nickel, nickel sulfate
13. POVIDONE IODINE.
14. iodinated glycerol
15. aloe vera topical
16. VACCINES
17. quinine and analogues
18. Tegaderm. Adhesive, or this product?
19. sulfa topicals

Closed Questions

1. Include substances only, or also null and negative values?
   1. Use is the criterion: include what is used. Agreed 10/19
   2. Specific negatives are rare; we anticipate two (nka & nkda).
2. How do we confirm quality?
   1. Process
      1. Acquire maps.
      2. If count(maps) > 1 and they agree, status is ok.
      3. If count(maps) < 2, acquire more maps.
      4. If count(maps) > 1 and they disagree, review.
3. Encode and then combine, or combine and then encode?
   1. Encoding is required to combine
4. How do we weight lists?
   1. Use filtered rankings to assess divergence, but no weighting in frequency list.
5. Rank all substances from contributed lists, or only those to a chosen level (97%, 99%, etc.)?
   1. Identified substances with counts > 500 (individually ~0.0017%; aggregate 0.71%)
   2. Actually, 1000. 4/19/17.
   3. Include frequency ratios in resulting list; users may choose their own thresholds.
6. Salt forms of medications are not relevant to the purpose of this list. Incidences recorded as salt forms should be summed to the incidence of the general form (e.g., codeine sulfate as codeine).
   1. Salts in solution have limited effect on the active moiety. This does not mean that an intolerance reaction dependent on a salt is not possible; only that it is not common enough to merit inclusion in this list.
7. Route can be significant.
   1. Enterally administered aspirin does not cross-react with topical salycilates. Topical salycilates should be specified as topical. Similarly, sensitivity to topical iodine preparations is not cross-reactive with intravenously administered iodine.
      1. confirm cross-reactivity. whether iodine can be the problem is a different question.

Minutes

9 May 2017

12 April 2017

8 March 2017

2 February 2017

11 January 2017

28 December 2016

14 December 2016

16 November 2016

2 November 2016

19 October 2016