Renin-angiotensin-aldosterone system inhibitors as a risk factor for chronic subdural hematoma recurrence: A matter of debate

Objectives: Chronic subdural hematoma (cSDH) is a common central nervous system condition. Recent reports indicate that cSDH affects long-term prognosis; however, its definitive risk factors remain unknown. An antihypertensive drug, renin-angiotensin-aldosterone system inhibitors (RAASi), can affect vascular permeability and cell proliferation processes, which may suppress the recurrence of cSDH. However, several studies have reported negative results to this effect. Therefore, we aimed to evaluate antihypertensive drugs, including RAASi, as risk factors for recurrent cSDH.Materials and methods: A total of 203 consecutive cases of surgically treated cSDH were retrospectively reviewed. Clinical and radiological parameters were compared between the groups with and without cSDH recurrence to identify risk factors.Results: Of the included cases, 68 (33.5%) used RAASi and 37 (18.2%) developed recurrence within 60 days of surgery. In the multiple logistic regression analysis adjusted by composite risk score, the odds ratios (95% confidence interval) of RAASi, calcium channel blockers, diuretics, & beta; and & alpha; blockers, for the recurrent risk of cSDH after surgery were 2.49 (1.16, 5.42), 1.79 (0.84, 3.82), 1.83 (0.62, 4.87), 0.90 (0.28, 2.44), and 0.96 (0.21, 3.20), respectively. The Cox proportional hazard model also demonstrated that RAASi-use was an independent risk factor for cSDH recurrence.Conclusions: Present series suggests RAASi-use as a risk factor for cSDH recurrence, although the role of RAASiuse in cSDH remains debatable. Further studies for deeper understanding of the microenvironment of hematoma and the surroundings are preferable. (235 words)