Date of Award


Degree Type


Degree Name

Master of Science in Pharmaceutical Sciences


Biomedical and Pharmaceutical Sciences

First Advisor

Stephen Kogut



Inflammatory bowel disease (IBD) describes gastrointestinal inflammatory diseases Crohn’s disease (CD) and ulcerative colitis (UC). The inflammation associated with CD can penetrate deep layers of gastrointestinal tissue anywhere along the gastrointestinal tract. Pharmaceutical therapy options for CD include aminosalicylates, corticosteroids, antimicrobials, immunomodulators, and biologics. The step-up (SU) treatment strategy for CD begins with anti-inflammatory agents (aminosalicylates, corticosteroids, and antimicrobials), and progresses to immunomodulators and biologics if disease control is not achieved. Conversely, with top-down (TD) therapy strategy, patients initiate CD medication treatment with immunomodulators and biologics and use anti-inflammatory agents as second-line options. Presently, limited evidence exists characterizing the utilization and short-term costs related to SU and TD therapy in CD.


The objective of this thesis research was to observe patient/disease characteristics in patients initiating CD pharmaceutical treatment with SU and TD therapy, and to examine predictors of increased first-year healthcare expenditures in a real-world setting.


This was a retrospective, cohort analysis of Optum’s de-identified Clinformatics® Data Mart Database examining patients with CD who were newly initiated on medication therapy from 2010 to 2018. Patients with CD were identified as having two International Classification of Diseases (ICD) codes for CD that were at least 30 days apart. The first CD-ICD code was considered the index diagnosis date. The SU and TD cohorts were defined based on medications for CD dispensed in the 60-day exposure period after the index diagnosis date. We examined 365 days prior to the index diagnosis to exclude patients not newly initiated on therapy, and 365 days after the exposure period to examine costs. We conducted a descriptive analysis comparing the SU and TD cohorts and used t-tests, chi-squared tests, and analyses of variance (ANOVA) to test the statistical significance of group differences. Predictors of per-patient average adjusted CD-specific healthcare cost were estimated using a generalized linear model.


We identified 3,157 patients newly initiating medication therapy for CD, with 2,392 patients in the SU cohort and 765 patients in the TD cohort. The SU cohort consisted of a larger proportion of females than the TD cohort (55.02%, 49.67%, respectively, p=0.0009) and the mean age in the SU cohort was higher than the TD cohort (48.9 years, 39.8 years, respectively, p

Discussion and Conclusion:

To our knowledge, this is the first study to use a large administrative claims database to compare the utilization and first-year healthcare expenditure among patients initiating medication therapy for CD with either SU or TD approach. We found that while the SU approach was the dominant treatment strategy, the proportion of TD therapy utilization increased over time. Furthermore, TD was associated with a higher overall and CD-specific cost in the year following treatment initiation. Further research is needed to determine the long-term overall healthcare costs associated with these strategies.



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