Physiological and pathological covariates of persistent concussion-related fatigue: results from two regression methodologies

ABSTRACT

Background: Fatigue severity in persons with mild traumatic brain injury (mTBI) has received little research attention, despite its typically positively skewed nature. Investigation of covariates across a range of fatigue severity may provide insight into important contributors.

Objective: To assess the relative significance of a priori-hypothesized covariates of physiological and pathological (mental and physical) fatigue in persons with mTBI/concussion, applying ordinary least squares (OLS) and quantile regression (QR) approaches.

Methods: We conducted a cross-sectional investigation in 80 participants with mTBI/concussion (mean age 45.4 ± 10.1 years, 59% male). The fatigue severity scale (FSS) was used as an outcome measure. Predictors of this outcome, grouped into physiological and pathological models of fatigue were assessed using OLS and QR.

Results: The mean total FSS score was 46.13 ± 14.59, and the median was 49 (interquartile range 37–57), demonstrating positive skewness. Fatigue severity was associated with variables within the mental, psychological and psychiatric domains at different levels of the fatigue score distribution.

Conclusion: Results highlighted that some covariates had a significant impact on the FSS total score at non-central parts of its distribution, while others exhibited significant impact across the entire distribution. Addressing covariates of fatigue across the severity continuum can enhance research and clinical management.

KEYWORDS:

• Concussion
• fatigue
• ordinary least squares
• quantile regression
• patient reported outcomes

Acknowledgments

We would like to express our sincere gratitude to Shirin Mollayeva for her assistance in checking data, the organization of the figures and proofreading the final version of the manuscript.

Disclosure statement

The authors have no financial or non-financial conflicts of interest to declare pertaining to this work. During the work on this study, the first author was supported by the Frederick Banting and Charles Best Research Award from the Canadian Institutes of Health Research and a research grant from the Alzheimer’s Association (#AARF-16-442937). The last author is supported by the Canadian Institutes for Health Research Grant–Institute for Gender and Health (#CGW-126580). The funders had no role in study design, data collection, decision to publish, or preparation of the manuscript.

Supplementary material

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Additional information

Funding

This work was supported by the Alzheimer’s Association [AARF-16-442937]; Canadian Institutes for Health Research, Institute for Gender and Health [CGW-126580].