Day-Night Variability of Hematoma Expansion in Patients with Spontaneous Intracerebral Hemorrhage

The levels of several coagulation factors, able to influence hemostatic balance, display circadian variations. We hypothesized that the onset and extent of hematoma expansion (HE) following intracerebral hemorrhage (ICH) also display diurnal patterns. We reviewed clinical, laboratory, and radiological data from 111 consecutive patients with spontaneous ICH who had baseline head computed tomography (CT) scans within 3 h of ICH onset and follow-up CT during the following 72 h. We defined any HE (AHE) as any increase in hematoma volume from baseline to follow-up CT and significant HE (SHE) as an absolute increase in hematoma volume >6 mL or relative increase >33%. We categorized the patients into 2 groups based on the timing of the initial CT scansday group (from 0800 to 2000 h) and night group (from 2000 to 0800 h)and performed logistic regression analyses. We also analyzed the differences in the rates of HE between the groups during six 4-h periods spanning 24 h, using (2) tests. We found that the rates of AHE and SHE were higher in the day versus night group (75% vs. 48%; p = 0.009 for AHE and 47.6% vs. 25.9%; p = 0.047 for SHE). On multivariable logistic regression, day group assignment was independently associated with AHE (adjusted odds ratio = 3.53; p = 0.008) but not with SHE. Both AHE and SHE peaked in the early afternoon (1200-1600 h) and reached a nadir during the 2000 to 2400 h time period, and they were significantly different between the time periods (0000-0400, 0400-0800, 0800-1200, 1200-1600, 1600-2000, and 2000-2400 h); p = 0.002 and 0.029, respectively. These exploratory findings support the presence of a daily pattern in the occurrence of HE, with a higher risk during the day hours. Our results could have implications for future therapeutic efforts targeting HE in ICH and for the triage of ICH patients. They require further validation.