**1. Introduction**

The physical, cognitive and emotional consequences of traumatic brain injury (TBI) may have a substantial negative impact on daily life functioning and quality of life [1,2]. The goal of TBI rehabilitation is to maximize the final outcome and preferably restore the preinjury functional level. Specialized TBI rehabilitation is provided by multidisciplinary teams working in a coordinated effort. Ideally, such rehabilitation should start as soon as the patient is in a medically stable phase and would be part of an uninterrupted chain of treatments (direct pathway). Studies have shown improved outcomes for patients who receive more intense and early initiation of rehabilitation and follow a direct pathway into rehabilitation [3–6]. However, this goal may not be achievable in all patients. It appears that only 41–50% of patients with severe TBI are referred directly from regional acute care to brain injury rehabilitation units [7–9]. Furthermore, direct pathway interruptions may have a negative effect on functional outcomes for individuals with severe TBI [8,10].

**Citation:** Tverdal, C.; Andelic, N.; Helseth, E.; Brunborg, C.; Rønning, P.; Hellstrøm, T.; Røe, C.; Aarhus, M. In the Aftermath of Acute Hospitalization for Traumatic Brain Injury: Factors Associated with the Direct Pathway into Specialized Rehabilitation. *J. Clin. Med.* **2021**, *10*, 3577. https://doi.org/10.3390/ jcm10163577

Academic Editor: Risto A. Kauppinen

Received: 15 July 2021 Accepted: 11 August 2021 Published: 14 August 2021

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Clinical factors positively associated with access to TBI rehabilitation include more severe injury (moderate to severe TBI), intracranial and extracranial surgery, length of stay and impaired function [11,12]. Studies determining the predictive value of demographics demonstrate that younger age is associated with discharge to rehabilitation and that the association of sex is uncertain [13]. Social factors negatively associated with access to rehabilitation are low level of education, unemployment, and substance abuse [8,11,12,14]. In stroke patients, studies suggest that reduced preinjury functional levels negatively influence the decision to refer to rehabilitation [15,16].

In 2012/2014, we published a quasi-experimental study that evaluated whether early initiation of a continuous care and rehabilitation pathway could improve functional outcomes and reduce hospitalization costs for patients with severe TBI [3,17]. We noted that patients with a continuous pathway through treatment had better functional outcomes 12 months postinjury. Across a 5-year period, TBI-related hospitalization costs were reduced, including those for inpatient rehabilitation, and improved outcomes were observed for the patients (under reasonable assumptions) [3,17]. Despite this knowledge, there is a concern that a significant number of patients are still not included in the direct care pathway. Furthermore, hospitals and patient populations are dynamic; thus, there is a constant need for evaluating clinical practice. The study aims to provide an updated overview of discharge to rehabilitation following acute traumatic intracranial injury over a 5-year period (2015–2019) and identify factors associated with a direct pathway to rehabilitation from acute care units.
