Decreasing prevalence or increase in unregistered cases of bulimia nervosa in children and adolescents in Germany? A comparison using representative claims data pre- vs. intra-COVID-19 pandemic.

Purpose: The aim of this study was to analyze data of children and adolescents in Germany insured according to legal requirements (statutorily insured) regarding epidemiology, comorbidities, and care of bulimia nervosa (BN) pre- vs. intra-COVID-19 pandemic.

Methods: The study is based on anonymized claims data of 10-17.9 years old children and adolescents statutorily insured in Germany from the InGef Berlin GmbH research database. The database combines data of more than 50 statutory health insurances and is representative of the German population. Prevalence, (quarterly) incidence, comorbidities and in- and outpatient treatment of BN (ICD-10: F50.2/F50.3) pre-COVID (01/2018-03/2020; N = 282,711) vs. intra-COVID (04/2020-12/2021; N = 282,738) was compared using descriptives and χ² tests, Welch-tests and interrupted time series analysis. The analysis was stratified by age groups (children: 10-13 years; adolescents: 14-17 years).

Results: Prevalence of BN was 0.09% pre-COVID and 0.07% intra-COVID (OR = 0.78 [0.65, 0.93]). After pandemic onset, a positive trend in the quarterly incidence among adolescents was observed (p = .016). Outpatient visits to general practitioners decreased (OR = 0.59 [0.35, 0.98]).

Conclusion: The observed decline in diagnosed and treated BN cases and the positive trend in quarterly incidence could be attributed to an increase in unregistered cases due to the overburdened care situation that emerged with the onset of the COVID-19 pandemic. Researchers and healthcare providers need to be aware of the potential for a backlash and deterioration/chronification of BN symptoms in children and adolescents. Level of evidence No level of evidence.