OBJECTIVES: Hypothalamic obesity (HO) is defined as abnormal weight gain resulting in severe persistent obesity due to physical damage of the hypothalamus, often from tumors and/or approaches used to treat these tumors. Yet, data on epidemiology of HO are almost entirely lacking.

METHODS: We developed an algorithm for the standardized identification of tumor-related HO patients and estimated the nine-year incidence rate of HO in the German healthcare context using a retrospective cohort study (n=5.24Million) covering 2010-2019. We included patients with surgery or radiotherapy and prior HO-associated tumor diagnosis (n=3,976). HO was further validated by incident obesity and diabetes insipidus diagnoses and desmopressin prescriptions within the quarter of surgery/radiotherapy or the following four quarters. Sensitivity analyses are used to account for uncertainty of the validation approach.

RESULTS: The estimated nine-year incidence of tumor-related HO in Germany is 0.68 cases per 100,000 persons (approx. 80 patients/year, lower bound 2019-prevalence approx. 1,260 patients). Two incidence peaks are observed: children/young adults aged 10-24 years and adults aged 40-44 years. 16% of HO patients are below 20 years, 14% above 65 years of age. Mean age is 38 years (SD: 18.0), whereas the age distribution depends on the underlying HO-associated tumor. The most frequent HO-validated tumor diagnoses are benign sellar and suprasellar tumors (0.61/100,000), including tumors of the craniopharyngeal duct (0.31/100,000), neoplasms of the pituitary gland (0.41/100,000), and nonspecific brain tumors of endocrine glands (0.24/100,000) (note: including patients with coding of two or more tumor entities). Extending the HO-validation period to prevalent obesity patients does not significantly affect incidence estimations.

CONCLUSIONS: Due to the lack of coding standards, identification of HO patients is associated with uncertainty. To our knowledge, this is the first claims database analysis of tumor related HO incidence, which contributes to a better understanding of the diseases administrative documentation and its relevance to health care systems.