Identification, epidemiology, and chronicity of pediatric esophageal eosinophilia, 1982-1999

Abstract

Background: Eosinophilic esophagitis (EE) is now a commonly encountered disorder that was rarely diagnosed a decade ago.

Objective: We aimed to determine the epidemiologic and histologic features of retrospective pediatric esophageal eosinophilia before the first case of EE at our institution was recognized.

Methods: Esophageal biopsy specimens obtained between 1982 and 1999 with reflux esophagitis were re-examined and reorganized into 2 groups based on peak esophageal eosinophil number (<15 eosinophils per high-powered field [hpf] and > or =15 eosinophils/hpf). The epidemiology and histology of the entire cohort and a population-based cohort were evaluated.

Results: Eight hundred seven biopsy specimens from 666 patients were re-examined; 198 patients had 15 eosinophils/hpf or greater. Among a population-based cohort of patients with 15 eosinophils/hpf or greater, there was a modest increase in incidence (P < .001; incidence rate ratio, 1.18; 95% CI, 1.09-1.28). After correcting for a 40-fold increase in the number of endoscopies during this time period, the proportion of biopsy specimens with 15 eosinophils/hpf or greater did not change (0.08 in 1982 vs 0.08 in 1996 [peak]; P = .9; incidence rate ratio, 1.02; 95% CI, 0.73-1.44). Patients who had as few as 5 eosinophils/hpf were more likely to have persistent esophageal eosinophilia on repeat esophagogastroduodenoscopy, evidence of basal layer hyperplasia, and lamina propria fibrosis compared with patients with less than 5 eosinophils/hpf (P < .001).

Conclusions: Esophageal eosinophilia at levels consistent with EE was present among 30% of patients given diagnoses of reflux esophagitis, and the incidence of esophageal eosinophilia did not change over time. Patients with 5 eosinophils/hpf or greater had evidence of other histologic abnormalities and were likely to have persistent esophageal eosinophilia.

Figure 1. Initial Study Cohort identification

Between 1982 and 1999, a total of 3,817 esophageal biopsies were obtained and 666 patients met study criteria. Upon reevaluation, 198 of these patients had ≥ 15 eos/hpf on esophageal biopsy.

Figure 2. Histologic Re-evaluation

Patients with 5 – 14 eos/hpf and ≥ 15 eos/hpf were more likely to have basal layer hyperplasia than patients with < 5 eos/hpf (*p < .001) and < 15 eos/hpf (**p < .001), respectively. Examples of basal layer hyperplasia and surface layering (b), lamina propria fibrosis (c) and microabscesses (d) are shown.

Figure 3. Chronicity of Initial Esophageal Eosinophilia (≥ 15 eos/hpf)

Among the 47 patients with ≥ 15 eos/hpf and at least 2 esophageal biopsies, the peak eosinophil count for each biopsy is shown. The solid line represents 15 eos/hpf and the dashed line represents the median eosinophil level for each group.

Figure 4. Odds Ratio of Repeat EGD as a Function of Initial Peak Eosinophil Count

The odds ratio and 95% CI of repeat EGDs with biopsy as a function of the initial eosinophil count is shown. An odds ratio of 1 is represented by the dotted line. (*p < .01, **p < .001)

Figure 5. The Incidence of Esophageal Eosinophilia Over Time

The number of incident biopsies with ≥ 15 eos/hpf occurring each year is shown* (a). The number of incident biopsies with ≥ 15 eos/hpf, < 15 eos/hpf and all other esophageal biopsies is displayed (b). The proportion of biopsies with ≥15 eos/hpf per year is shown. (*p < .001).