There is no Seasonal Variation but Regional Variation Exists Between Adults and Children in Hospitalization Rates of Eosinophilic Esophagitis (EoE) in the United States

Abstract

Introduction: Prior studies have shown that incidence of EoE has been rising and EoE may have a seasonal and regional variation. We hypothesize that the hospitalization rates for EoE has been rising in both pediatric and adult population in the United States. We also hypothesize that the hospitalization rates between the two age groups vary with seasons and geographical location. Methods: Between 2009 to 2012, data was extracted from the National Inpatient Sample on all patients with Eosinophilic Esophagitis (ICD 9 CM: 530.13). Information prior to 2008 was excluded as EoE was given a specific ICD 9 Code only in 2008. In order to remove bias and confounding factors which may mimic symptoms of EoE, exclusion criteria was applied (ICD 9 CM:530.81, 530.85, 530.0, 530.5, 530.6, 530.10, 530.11, 530.12, 530.19, 150). Hospitalization rates of EoE were analyzed annually for all age groups during the study period. EoE Hospitalization rates were also assessed for four seasons (Summer, Spring, Fall and Winter), for each of the US States and Urban versus Rural Location in the US. Analyses were performed using SAS version 9.3. Results: During the study period, a total of 2004 patients with EoE were admitted to the hospitals in United States. Of these, 1180 cases were of adult EoE and 824 cases of pediatric EoE were identified.We noted that the EoE related hospitalization rates increased to 924 in 2012 from 567 in 2009 with higher rates for adults compared to children (P<0.0001) [Fig 1A].There was no significant seasonal variation in hospitalization rates of EoE between adults and children [Fig 1B]. Hospitalization rates varied among the US states with highest rates in some states with dry environment (Arizona, California, Florida, Texas) and lowest among the others with colder climate (North Dakota, Maine, South Dakota) [Fig 2].Similarly, the hospitalization rates were highest in the Central counties of metro areas of >=1 million population and lowest for Not metropolitan or micropolitan counties, significantly higher for adults compared to children (P=0.01) [Fig 3].Figure: Annual Hospitalization Trends of EoE Fig 1B: Seasonal Variation in Hospitalization of EoE.Figure: US State-Wise Hospitalization Trends of EoE.Figure: Urban vs Rural Hospitalization Trends of EoE.Conclusion: EoE related hospitalization has been rising in the United States. We note that EoE doesn't have a seasonal variation in diagnosis and hospitalization between adults and childen. We highlight that urbanization and residence in areas with dry and arid climate may have played a role in the pathogenesis and the rising trends of EoE with significant effect in adults. Further studies are needed to confirm these findings.