Risk factors for recurrent acute mastoiditis in pediatric patients: a registry-based cohort study

Abstract Objective To describe characteristics of pediatric patients with recurrent acute mastoiditis, and to identify risk factors for this condition. Study design A retrospective cohort study. Setting Data based on electronic medical records of the largest Health Maintenance Organization in Israel. Methods Children hospitalized due to acute mastoiditis during the years 2008–2018 were identified, and their diagnosis was verified. Patients with recurrent acute mastoiditis were identified and grouped, and their characteristics were outlined and compared to those of the original group to identify risk factors for recurrence. Results During the 11-year period, a total of 1115 cases of children hospitalized due to acute mastoiditis were identified with a weighted incidence rate of 7.8/100,000. Of this group, 57 patients were diagnosed with recurrence following a full clinical recovery. The incidence proportion of recurrent acute mastoiditis was 5.1% (57/1115), male-to-female ratio was 27:30, 73.4% were younger than 24 months, the median period from the first episode was 3.4 months (IQR 2.0;10.0), and 82.5% of the patients (n = 47) had a single recurrence, whereas 18.5% (n = 10) had two recurrences or more. Mastoidectomy and swelling over the mastoid area during the first episode were identified as the main risk factors for recurrent mastoiditis HR = 4.7 [(2.7–8.2), p < 0.001] and HR = 2.55 [(1.4–4.8), p = 0.003], respectively. Mastoidectomy was the only independent significant risk factor for recurrence in a multivariate analysis. Conclusions Mastoidectomy and swelling over the mastoid area during the first episode of acute mastoiditis were found strongly related independent risk factor for future recurrent episodes of acute mastoiditis.