Abstract
BACKGROUND: Prestroke physical activity (PA) has been linked to improved outcomes after intracerebral haemorrhage (ICH), but its association with ICH volume is unknown. We aimed to investigate associations of prestroke PA with location-specific haematoma volume and the clinical outcome of ICH. METHODS: All patients with primary ICH, admitted to three hospitals between 2014 and 2019, were included. Patients performing light PA ≥4 hour/week the year before stroke were considered physically active. Haematoma volumes were assessed from admission brain imaging. Adjusted associations were estimated using multivariate linear and logistic regression models. Haematoma volume was explored as mediator to the relationship between prestroke PA and mild stroke severity (0-4 points on the National Institutes of Health Stroke Scale), a good 1-week functional status (0-3 points on the modified Rankin Scale) and 90-day survival. Average direct effects (ADE) and average causal mediation effects (ACME) were computed. RESULTS: Of 686 primary ICH cases, 349 were deep, 240 lobar and 97 infratentorial. Prestroke PA predicted smaller haematoma volumes in deep ICH (β=-0.36, SE=0.09, p<0.001) and lobar ICH (β=-0.23, SE=0.09, p=0.016). Prestroke PA was also associated with mild stroke severity (OR 2.53, 95% CI 1.59 to 4.01), a good 1-week functional status (OR 2.12, 95% CI 1.37 to 3.30) and 90-day survival (OR 3.48, 95% CI 2.06 to 5.91). Haematoma volume partly mediated the relationships between PA and stroke severity (ADE 0.08, p=0.004; ACME 0.10, p<0.001), 1-week functional status (ADE 0.07, p=0.03; ACME 0.10, p<0.001) and 90-day survival (ADE 0.14, p<0.001; ACME 0.05, p<0.001). CONCLUSIONS: Light PA ≥4 hour/week prior to ICH was associated with smaller haematoma volumes in deep and lobar locations. Physically active patients with ICH had a higher likelihood of mild stroke, a good 1-week functional status and 90-day survival, in part mediated by smaller haematoma volumes on admission.