1396. Risk Factors for Brain Abscess: A Nationwide Population-based Nested Case–Control Study

Abstract

BackgroundKnowledge of risk factors for brain abscess is limited and relies on single-center cohorts without control groups.MethodsWe accessed nationwide medical registries to conduct a population-based nested case–control study of risk factors for brain abscess. We applied risk set sampling for selection of population controls (1:10) individually matched by age, sex, and area of residence. Conditional logistic regression was used to compute adjusted odds ratios (aOR) with 95% confidence intervals (CIs). Next, population attributable fractions were calculated.ResultsWe identified 1,384 brain abscess patients in Denmark from 1982 through 2016 and 13,839 matched population controls. The median age was 50 years (interquartile range 33–63) and 37% were female. Cases often had a Charlson comorbidity score>2 (16%) compared with controls (3%). Adjusted ORs were: head trauma 2.15 (1.72–2.70), neurosurgery 19.3 (14.3–26.0), dental infection 4.61 (3.39–6.26) or surgery 2.57 (1.71–3.84), ear-nose-throat infection 3.81 (3.11–4.67) or surgery 2.85 (2.21–3.70), congenital heart disease 15.6 (9.57–25.4), diabetes mellitus 1.74 (1.33–2.29), alcohol abuse 2.22 (1.58–3.11), liver disease 2.37 (1.53–3.68), kidney disease 2.04 (1.30–3.20), and lung abscess or bronchiectasis 8.15 (3.59–18.5). The aORs were 4.12 (3.37–5.04) and 8.77 (5.66–13.6) for solid and hematological cancer, 12.0 (6.13–23.7) for HIV, and 5.71 (4.22–7.75) for immuno-modulating treatments. Risks were twice as high when risk factors were observed within 5 years before brain abscess. Population attributable fractions showed that neurosurgery (12%), solid cancer (11%), ear-nose-throat infections (7%) and immuno-modulating treatments (5%) were substantial contributors to occurrence of brain abscess.ConclusionImportant risk factors included neurosurgery, cancer, ear-nose-throat infections and immuno-modulating treatments Disclosures All authors: No reported disclosures.