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Phenotype submission - Crohns disease

Cohort Definition Name : Earliest event of Crohns disease

Contributor name : Joel Swerdel’

Contributor OrcId : 0000-0002-6976-2594’

Logic Description : Earliest occurrence of Crohns disease indexed on diagnosis date, for the first time in history cohort exit is the end of continuous observation

Recommended study application : target

Assertion statement : This cohort definition was executed on at least one real person-level observational health data source and resulted in a cohort with at least 1 person.

Target Clinical Description : Crohn’s disease (CD) is an idiopathic inflammatory bowel disease that can affect any portion of the intestinal tract with focal, asymmetric, transmural, and granulomatous inflammation[1-3]. Crohn’s disease is characterized by chronic inflammation that may extend through all layers of the intestinal wall, involving the mesentery and regional lymph nodes. Intestinal involvement is discontinuous; “skip areas” of apparently normal tissue separate severely involved segments. Reported incidence varies geographically, ranging from 0-20.02 cases per 100,000 py in North America and 0.3-12.7 cases per 100,000 in Europe. Reported prevalence is highest in Europe (322 cases per 100,000 persons in Germany) and North America (319 cases per 100,000 persons in Canada) [4]. Risk factors include smoking, diet, and genetic factors.

Evaluation conclusion : We developed a prevalent cohort definition for Crohns disease (CD) using a concept set of two concepts which incorporated all those found from the literature review and from the analysis of PHOEBE and orphan concepts in cohort diagnostics. The algorithm retrieves subjects from all 11 databases tested. We developed a more specific cohort requiring a second diagnosis code for CD in the time period 31-365 days after index. This cohort improves the specificity of the algorithm albeit at the expense of sensitivity as determined by PheValuator. The significant loss in sensitivity, however, precludes its use as a tergte population. Performance characteristics were determined for 7 of the 11 databases. The remaining databases did not contain enough subjects to produce an accurate diagnostic model. Using this the deffinition, sensitivity ranged from about 63% in Germany to about 87% in CCAE and PharMetrics while positive predictive value ranged from about 70% in MDCR to about 79% in PharMetrics

Thanks @Azza_Shoaibi and @jswerdel for sharing the phenotype for Crohn’s disease. I plan to re-use this phenotype as a nesting indication within our HowOften effort for OHDSI2023.

Capturing a note as I reviewed this: Crohns is another example of a disease that get organized in multiple places in the SNOMED hierarchy. There are concepts for ‘Crohns’, but also separately there is a branch of ‘Complication due to Crohn’s disease’ (which I think are clear markers we’d want to use to identify persons with CD). It’s also curious that ‘Perianal Crohn’s disease’ isn’t a descendant of Crohns disease. This is a good demonstration of why using PHOEBE recommender system to pick up these items that could otherwise be missed is so important, and how being able to re-use phenotypes is so valuable because otherwise I could have missed those codes.

Imported to the OHDSI Phenotype Library. It may be expected to be found with id = 859 in the next release. Thank you