Proposed MID in FACIT and VAS scores for individuals attending COVID-19 rehabilitation

Abstract

<b>Background:</b> Fatigue is a common symptom post COVID-19 and may be addressed through rehabilitation programmes. The Functional Assessment Chronic Illness Therapy- Fatigue Scale (FACIT) is a validated tool; however, the Minimal Important Difference (MID) is unknown for people completing rehabilitation following COVID-19. We aimed to calculate the MID for the FACIT in these individuals and the relationship with a visual analogue score (VAS) of fatigue. <b>Methods:</b> FACIT and a VAS were completed pre and post rehabilitation. The programme consisted of 12 face to face supervised sessions over six weeks. Distribution methods were used to calculate the MID using 0.5 of standard deviation (SD) and standard error of measurement (SEM). Pearson’s correlation was used to compare FACIT and VAS scores. (Ethical reference approval 17/EM/ 0156). <b>Results:</b> 32 individuals were eligible for analysis (male 59.4%, mean [SD] age of 56[15] years). The mean [SD] change in FACIT score post rehabilitation was 4.6[7.2] (p&lt;0.01). The calculated MID was 3.6 (0.5xSD) and 2.7 (SEM). The mean [SD] change in VAS score was 2.1[2.2] (p&lt;0.01). The calculated MID was 1.1 (0.5xSD) and 0.6 (SEM). The FACIT and VAS score had a correlation coefficient of -.7 (p&lt;0.01) at baseline. <b>Conclusions:</b> We propose an MID range of 2.7 to 3.6 points in the FACIT and 0.6 to 1.1 points in the VAS fatigue score following a COVID-19 rehabilitation programme. A strong correlation was found between the FACIT and the VAS score. This has potential for clinical application where the VAS is quicker to implement. Further analysis in a larger population and use of an anchor-based method is required to support these findings.