Outcomes of chronic subdural hematoma with preexisting comorbidities causing disturbed consciousness.

OBJECTIVE Chronic subdural hematoma (CSDH) is widely treated by drainage through a bur hole opening. However, whether and how preexisting comorbidities causing disturbance of consciousness affect patient outcomes remains unclear. METHODS The authors analyzed 188 consecutive patients with CSDH who were surgically treated at the Neurosurgery Institute of the Kyorin University School of Medicine between 2010 and 2012 and followed them for more than 90 days. The mean patient age was 77.0 years (range 33-101 years) and 56 were women. Patient outcomes including modified Rankin Scale (mRS) score, postoperative morbidity and mortality, and recurrence 90 days after initial surgery were analyzed according to preexisting comorbidities causing disturbance of consciousness. The comorbidities observed in 46 patients (24%) included dementia (30 patients), history of ischemic stroke (10 patients), psychiatric disorders (3 patients), and others (3 patients). RESULTS Background characteristics of patients with comorbidities showed older patient age (p < 0.001), lower preoperative Glasgow Coma Scale score (p < 0.001), and higher preoperative mRS score (p < 0.001). The mean mRS score 90 days after the neurosurgical procedure was 1.2 in all 188 patients, which was significantly higher in those with comorbidities (p < 0.001). By 1-way ANOVA with repeated measures, interaction existed between the presence of comorbidities and mRS score, and improvement of mRS score was observed in smaller proportions of patients with comorbidities (p = 0.002). By multivariate logistic regression analysis, the presence of comorbidities, patient age, reoperation for recurrence, and preoperative mRS score were significantly related to poor outcomes, defined as mRS score of 3 or more at 90 days after surgery. Postoperative morbidity (p < 0.01) and mortality (p < 0.01) were significantly higher in those with comorbidities, whereas the rate of recurrence of CSDH was not significantly different. CONCLUSIONS The preexistence of comorbidities causing disturbance of consciousness affected severity and outcomes 90 days after surgical treatment of CSDH, and comorbidities were also correlated with aging.