A comparison of four schemes for codification of problem lists

We set out to evaluate the completeness of four major coding schemes in representation of the patient problem list: the Unified Medical Language System (UMLS, 4th edition), the Systematized Nomenclature of Medicine (SNOMED International), the Read coding system (version 2), and the International Classification of Diseases (9th Clinical Modification)(ICD-9-CM). We gathered 400 problems from patient records at primary care sites in Omaha and Seattle. Matching these against the best description found in each of the coding schemes, we asked five medical faculty reviewers to rate the matches on a five-point Likert scale assessing their satisfaction with the results. For the four schemes, we computed the following rates of dissatisfaction, satisfaction, and average scores: [table: see text] From this analysis, we conclude that UMLS and SNOMED performed substantially better in capturing the clinical content of the problem lists than READ or ICD-9-CM. No scheme could be considered comprehensive. Depending on the goal of systems developers, UMLS and SNOMED may offer different, and complementary, advantages.