Eosinophilic esophagitis and disease complications : register-based studies

Sammanfattning: This thesis presents four studies on Eosinophilic Esophagitis (EoE). The overall aim is to grasp the basics of epidemiologic research and use this understanding on EoE disease complications. EoE is a fairly new inflammatory disease with clinicopathological diagnosis that increases in prevalence. It is considered a relatively mild disease, but the evidence concerning mortality and morbidity is scarce. Although EoE has a prevalence peak in childbearing age, pregnancy outcomes are poorly examined. In Study I, a random portion of 131 patient charts from the cohort werecollected for a diagnosis validation through a patient chart review. EoE was found in 99 patients, which corresponds to a positive predictive value of 89%. The cohort was predominately male, and the most common symptom was dysphagia. Study II examines mortality in EoE individuals compared to matched reference individuals using survival analysis. We performed sibling analysis to adjust for intrafamilial (genetic and environmental) confounding. We found no elevated risk for death. Study III uses a similar method to find higher risk of psychiatric comorbidity among EoE patients compared to matched reference individuals. Mean follow-up time was 4.03 years, and there were 106 events of psychiatric disease in the EoE-group, which corresponds to an elevated risk of 50% compared to reference individuals. Study IV investigates outcomes of pregnancy in EoE females versus comparators. The main outcome is premature birth; in secondary analyses, we examined both maternal and fetal outcomes. The only elevated risk was low birth weight; although a significant finding, it was still based on a small sample size and should be interpreted with caution.