PTU-145 Incidence of Eosinophilic Oesophagitis in a New Zealand Population: A Retrospective Analysis

Abstract

Introduction Eosinophilic oesophagitis (EO) is the diagnosis in 10-15% of dysphagic patients in European and N American studies, most frequent in men aged less than 50 years. It is precipitated by aero-allergens. Diagnosis requires > 20 eosinophils per hpf on oesophageal biopsies. We investigated its incidence in a New Zealand population where the genetic profile is similar (92% NZ European descent) but the environmental exposure to flora very different. Methods A retrospective review of 871 patients investigated by gastroscopy for dysphagia from 2006-11 at Dunedin hospital. Age, sex, endoscopic findings and whether biopsied were recorded from the endoscopy database. Histology was determined from the hospital PAS system and equivocal cases reviewed by a consultant histopathologist. Sex and age differences were interrogated with chi-squared and P < 0.05 was considered significant. Results Average age of all patients was 68.7 years, 57.1% male. Common diagnoses were normal (27.7%), oesophagitis (21.7%), cancer (11.2%), dysmotility (7.3%), peptic stricture (5.0%). 20 patients (12 male, mean age 45.5 years) had EO. 5 of these had endoscopic abnormalities (2 x ridges, 2 x Schatzki rings, 1 x furrows). 351 patients (40.9%) had oesophageal biopsies, but only 86 of 434 where the underlying cause was not evidence ie no cancer, oesophagitis or peptic stricture. EO incidence was 2.3% of all patients, 5.7% of those biopsied but 23.2% of those where an alternative diagnosis was not evident. Annual incidence varied from 1.1 to 4%. The frequency of biopsies was greater in 2011 (73.6%) than previous years (26.9-44.1%) but the number of cases identified did not differ significantly (3.4-9.0% of those biopsied). (Table Presented) Conclusion EO appears less frequent in a New Zealand dysphagic population than in previous Northern hemisphere studies although this might be due to few biopsies where no macroscopic abnormality was seen. Biopsies are more frequent in men than women but EO no more likely. Biopsies are not more frequent in younger patients ( < 50 y.o) but EO is much more frequent. The exact incidence of EO and reasons for discrepancies with previous studies merit further investigation.