The association between obesity and clinical as well as radiological outcomes in patients suffering spontaneous intracerebral haemorrhage (ICH) remains unclear. The obesity paradox suggests a protective effect regarding in-hospital mortality. This study evaluates the impact of body mass index (BMI) on functional long-term outcome and bleeding volume in patients with spontaneous ICH.

A retrospective cohort study including all patients with spontaneous ICH between December 2017 and June 2021, aged 80 years or younger (n = 218), were included. Patients were dichotomized into overweight (OW, BMI ≥ 25 kg/m²) and normal weight (NW, BMI < 25 kg/m²). Functional outcomes were assessed at 1, 3, 6 and 12-months follow-up. To address potential sex-related bias, we conducted exploratory post hoc analyses.

Of 218 patients (66.04 ± 15.18 years) suffering spontaneous ICH, 115 (52.75 %) were OW (29.72 ± 3.82). Multivariate analysis revealed that independent significant predictors of a favourable 12-month functional outcome were smaller haematoma volume (p = 0.01) and symptom onset less than 6 h before arrival at our hospital (p = 0.018), whereas BMI was not, whether analysed dichotomously, continuously, or by WHO categories (p ≥ 0.41). Younger age showed to be a significant predictive factor for a better 12-month outcome in univariate analyses (p = 0.003), but lost significance in multivariate analyses (p = 0.14). Sex distribution (n = 72 females, n = 68 males; p = 1.0), NIHSS at admission (p = 0.69) and overweight prevalence (41.7 % vs. 55.9 %; p = 0.13) did not differ significantly between groups. Stratified BMI-outcome associations remained non-significant in both sexes (p = 0.39 for males, p = 0.21 for females).

Our data suggests that in patients suffering from spontaneous ICH, haematoma volume and age, are independent negative predictors for functional outcome in the long-term. BMI was not associated with 12-month outcome after adjustment, while early presentation (within 6 h of symptom onset) predicted favourable 12-month outcome.