Supplementary Material for: Ambient Temperature and Severity of Intracerebral Haemorrhage: The INTERACT1 Study

Background: Intracerebral haemorrhage (ICH) rates increase in winter months. We aimed to determine associations of ambient temperature with clinical severity and haematoma size in acute ICH among Chinese participants in the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT1). Methods: INTERACT1 was a randomised controlled trial of early intensive blood pressure lowering in 404 patients with acute ICH. Among 304 (79%) Chinese participants, data on ambient temperature (average, minimum, maximum and range) on the day of ICH onset obtained from the China Meteorological Data Sharing Service System were linked to measures of clinical severity: elevated National Institute of Health Stroke Scale score (>10), low Glasgow Coma Scale score (<14), and haematoma parameters at the time of presentation. Clinical outcomes were evaluated in logistic regression models, and haematoma volume (log transformed, with and without intraventricular haemorrhage, IVH) was evaluated in multivariable regression models. Results: No significant associations were evident between temperature parameters and clinical parameters and haematoma volume (with and without IVH), even after adjustment for key prognostic factors. Conclusions: No relationship was evident between ambient temperature and severity in acute ICH.