Impact of Clinical and Sociodemographic Factors on Fatigue Among Patients With Substance Use Disorder: A Cohort Study From Norway for The Period 2016-2020

Abstract Background The impact of clinical and sociodemographic factors on fatigue remains unknown among patients with substance use disorders (SUD). This study aims to evaluate fatigue among patients with SUD using a nine-item fatigue severity scale (FSS-9) and identify the impact that clinical and sociodemographic factors – such as injecting substance use, chronic infectious diseases, liver fibrosis, opioid agonist therapy (OAT), debt difficulties, and housing situation – have on fatigue.Methods We used data from a cohort of patients with SUD in Norway with annual health assessments surveying FSS-9 and some clinical and sociodemographic factors. A total of 915 FSS-9 measurements were collected from 654 patients during the period 2016-2020. We defined baseline as the first annual health assessment when the health assessments were listed chronologically. Time was defined as months from baseline. We used a linear mixed model to analyse whether the clinical and sociodemographic factors affected the FSS-9 sum score, presented with beta coefficients (β) with 95% confidence intervals (CI). Results The mean sum score of the FSS-9 was 43 (standard deviation: 16) at baseline. Being female (change in FSS-9 sum score: 4.1, 95 % CI: 1.3-7.0), having debt difficulties (2.9;0.4-5.3), and using benzodiazepines (5.7;3.0-8.4), amphetamine or cocaine (-5.0;-8.0--2.0) affected the FSS-9 sum score. The other clinical and sociodemographic factors did not predict any clinically relevant change in the FSS-9 sum score from baseline to the following health assessments.Conclusion Patients with SUD suffer from high levels of fatigue. Focusing on closer follow-up of females and reducing debt difficulties and the use of benzodiazepines may mitigate fatigue in the SUD population.