Determining the Minimally Clinically Important Difference for the Disability Rating Scale in Persons With Chronic...

Area of Science:

• Neuroscience
• Clinical Neurology
• Rehabilitation Medicine

Background:

• The Extended Glasgow Outcome Scale (GOSE) is the primary outcome in traumatic brain injury (TBI) studies.
• The Disability Rating Scale (DRS) assesses functional progress in chronic TBI.
• Establishing a minimally clinically important difference (MCID) for the DRS is crucial for its use in research.

Purpose of the Study:

• Determine the MCID for the DRS in chronic TBI.
• Establish the DRS change magnitude associated with a 1-point GOSE MCID.

Main Methods:

• Retrospective analysis of the Traumatic Brain Injury Model Systems National Database.
• Longitudinal data from 1, 2, and 5 years post-injury.
• Spearman's correlations to analyze DRS and GOSE relationships.
• Triangulation method using dynamic and static MCID estimates.

Main Results:

• A significant correlation was found between DRS and GOSE scores.
• Dynamic MCID estimate for DRS was -0.68 points.
• Exploratory static MCID estimate for DRS was -1.28 points.
• The final MCID for DRS, using triangulation, was calculated as -1.0 point.

Conclusions:

• A -1.0-point change on the DRS represents a minimally clinically important difference in chronic TBI.
• The established MCID supports the DRS as a viable alternative primary outcome measure for TBI research.
• This finding enhances the utility of the DRS in clinical trials and long-term TBI outcome studies.