Obesity Paradox and Surgical Evacuation for Chronic Subdural Hematoma.

BACKGROUND

Chronic subdural hematoma (cSDH) has a number of risk factors for recurrence, and some studies suggest obesity is one of them. Yet obesity has been shown to have a positive survival benefit in many diseases such as ischemic stroke, chronic obstructive pulmonary disease, percutaneous coronary intervention, and mechanical thrombectomy. Therefore, we sought to determine if obesity provided a mortality benefit in patients with cSDH undergoing burr hole drainage or craniotomy.

METHODS

We performed a retrospective database analysis using a multi-institutional (TriNetX) database looking at obese versus non-obese patients with cSDH undergoing surgical drainage. Our primary endpoint was mortality. Secondary endpoints included seizure, pulmonary embolism (PE), myocardial infarction (MI), cerebral infarction, deep vein thrombosis (DVT), tracheostomy, and percutaneous endoscopic gastrostomy (PEG). These were looked at to obtain a better idea of prognosis. Cohorts were propensity score-matched for confounders, using the greedy-nearest neighbor algorithm with a caliper of 0.1 pooled standard deviations. Kaplan-Meier survival curves were also developed, and hazard ratios were calculated. Chi-square analysis was performed on categorical variables.

RESULTS

A total of 1,849 patients were identified as obese with a drainage procedure, while 12,371 were identified as non-obese. Some 1,746 patients remained in each group after propensity score matching. Thirty-day survival rates were 88.08% in the obese vs. 83.82% in the non-obese cohorts, 90-day survival 85.15% vs. 79.35%, 365-day survival at 80.89% vs. 71.90%, and five-year survival at 64.75% vs. 54.84% (p < 0.0001). The risk difference was -8.02% (95% confidence interval, Cl -11.02, -5.021%); relative risk, RR 0.757, 95% Cl (0.67, 0.841); odds ratio, OR 0.676 (0.583, 0.783); p < 0.0001). Seizures, ventilator dependence, MI, cerebral infarction, tracheostomy, and PEG rates were all non-significant. Obese patients had a higher rate of PE (7.90% vs. 4.47%, p < 0.0001) and DVTs (12.37% vs. 10.02%, p = 0.0278).

CONCLUSIONS

Obesity in patients with cSDH undergoing surgical evacuation is associated with decreased mortality but higher rates of DVT and PE.