Incidence of hydrocephalus in traumatic brain injury A nationwide population-based cohort study

Background: The aim of this study was to investigate the risk and peak time of post-traumatic hydrocephalus (PTH) in traumatic brain injury (TBI) patients with traumatic subarachnoid hemorrhage (SAH), compared to TBI patients without traumatic SAH. Methods: In this retrospective population-based cohort study, the data was extracted from Longitudinal Health Insurance Database from 2000 to 2010 in Taiwan. A total of 23,775 TBI patients who had a first event TBI during 2000 to 2010 were included and divided into TBI with SAH (TBI-S) group and TBI without SAH (TBI-NS) group. We focused on analyzing the PTH in both groups within 2 years after brain injury. Competing risk regression models were performed to assess the risk of developing PTH in the TBI-S group compared to the TBI-NS group. Results: Comparing to the TBI-NS group, there was a significantly higher cumulative incidence of PTH in the TBI-S group during the 2-year follow-up period. The adjusted hazard ratio (HR) of PTH in TBI-S group within 2 years was between 2.90-3.47, and the highest estimates were obtained within 6 months after injury (HR= 3.47, 95% CI: 2.43-4.94). The occurrence percentage of PTH was highest during 0-3rd month follow-up periods (1.95% in TBI-S group; 0.48% in TBI-NS group). Conclusions: The peak time of PTH occurrence was noted during 0-3rd month post brain injury. Traumatic SAH patients had an approximate 3-fold risk of developing PTH, comparing to TBI patients without traumatic SAH.