Effects of Pre-Existing Comorbidities on Outcomes in Patients with Chronic Subdural Hematoma.

Objective: The number of patients with chronic subdural hematoma (CSDH) showing comorbidities and/or impaired activities of daily living (ADL) before the onset of CSDH has increased with the recent aging of society. The purposes of this study were to evaluate ADL worsening by comparing premorbid ADL and ADL at discharge and to investigate the effects of pre-existing comorbidity-related clinical factors on the outcomes.

Methods: A total of 570 patients with CSDH admitted from 2006 to 2016 were studied retrospectively. Clinical factors, including pre-existing comorbidities, related to outcomes were identified by multivariate analysis. A variation of the modified Rankin Scale (mRS) using 5 united categories of mRS scores 0/1, 2, 3/4, 5, and dead was used for evaluation of ADL.

Results: Of 570 patients, 390 (68.4%) had pre-existing comorbidities and 120 (21.1%) showed premorbid impaired ADL (mRS scores 2 and worse). Considering pre-existing impaired ADL, ADL deteriorated after CSDH in 92 patients (16.1%), whereas ADL impairment at discharge was found in 173 patients (30.4%). Comorbidities related to ADL deterioration on multivariate analysis were hemodialysis and chronic heart failure. Antithrombotic use for cardiovascular diseases was a predictor of acute-on-chronic subdural hematoma, which was the sole common predictor for ADL deterioration and the occurrence of surgical complications.

Conclusions: In patients with CSDH, pre-existing comorbidity-linked factors related to outcomes were hemodialysis, chronic heart failure, and antithrombotic use. Patients with acute-on-chronic subdural hematoma with these factors should be regarded as a high-risk group.