Does mapping to SNOMED CT improve precision of subjective

clinical evaluations?

SHI2010 presentationKirstine Rosenbeck Gøeg & Anne Randorff Rasmussen

INTRODUCTION

Semantic of clinical documentation

Ambiguous documentation

“Impairment of vision”

Worsening of something chronic

First diagnose

Impairment causing change of occupation

A problem?

• Interview 2009 “Vi har nogle begreber som vi har brugt i årevis, eksempelvis tilladelig blødning..... nogen der siger, at det er 100ml, mens andre siger at det er det i hvert fald ikke. Så der opdager vi, at vi ikke har den samme opfattelse. Så der må vi blive enige om at tilladelig blødning er under 100ml, hvis moren ellers har det godt, blodtrykket holder og hun ikke besvimer. Der var så meget mere, der skulle knyttes til sådan et begreb....”

• Rector 1999 “Common usage may differ from the expectations of information retrieval, e.g. it may seem odd to say that ‘The fingernail is a part of the arm’, but it would be an error not to retrieve ‘evulsion of nail’ under ‘trauma to upper extremity’.”

Interview 2009: http://projekter.aau.dk/projekter/files/17651356/speciale-rapportTilUdskrift.pdfRector 1999: Why is terminology so hard? Method Inform Med 1999; 38: 239–52

A problem?

• Increasingly possible to– Exchanging information

to perform shared care– Use data for statistical

purposes

• Characterised by– No input validation– Most likely to stay in one

organisation and being used only for patient treatment purposes

Semantic precision!

METHOD

Mapping subjective evaluations to SNOMED CT

Method• Two cases

– Tolerable bleeding/ Tilladelig blødning

– Eating too little/ Småtspisende

• Charaterised by– Real life examples of clinical

evaluations– From spring 2009– Expressed difficulties in

mapping from paper documentation to electronic documentation

• Three approaches to improve precision using SNOMED CT– Mapping to existing pre-

coordinated SNOMED CT terms consisting of a finding and a qualifier. Map the evaluation as is, without interpretation.

– Mapping by analysing the clinical situation/context in which the evaluation is obtained.

– Mapping by nesting the subjective evaluation with the rationale behind the evaluation.

RESULTS

SNOMED CT mappings

Existing pre-coordinated terms

Hemorrhage

Actute Massive Subacute ChronicDiffuse

Bleeding(finding)

Associated morphology

Finding of vaginal bleeding

Normal menstual Fresh Scanty Moderate Profuse Abnormal

Bleeding(finding)

Finding of quantity of eating

Binging Excessive Fasting Overeating

Finding of eating pattern

Picky eater Greediness

Adding the context of the finding

Finding: Tolerable bleeding

Context: During labour

Maternal blood loos within normal

limits

SNOMED CTmapping

Finding: Eating too little

Context: Screening, some time duration

Inadequate dietary caloric intake,

continual

Inadequate dietary caloric intake,

continual

Nesting observation and evaluation

DISCUSSION

Choosing between mappings

Discussion

• A study with only two clinical expressions – pros and cons

• Choosing between the three approaches?– Mapping directly is not recommended based on

the results of this study – Considering the clinical situation and

consequences of different mappings– Asking clinical experts

• Can levels of precision be pre-specified?

• Correspondence:Kirstine Hjære RosenbeckPhD Fellow, Aalborg UniversityDepartment of Health Science and Technology

E-mail: kirse@hst.aau.dkPhone:+45 9940 8835