Fatigue Severity Scale Valid Tool for assessing fatigue in patients with ILD

USA: A recent study published in the American Journal of Respiratory and Critical Care Medicine has found that the fatigue severity scale (FSS) is a reliable and valid patient-reported outcome measure for assessing fatigue in patients with Interstitial Lung Disease (ILD).

Fatigue is a common and debilitating symptom for those living with ILD, and previous studies have shown limited progress in developing interventions targeting improvement in fatigue. The purpose of this study was to determine the validity and reliability of the fatigue severity scale (FSS) for measuring fatigue in ILD patients.

The study involved 1,881 patients with ILD who completed the FSS questionnaire along with several other measures, including the Short Form 6D Health Utility (SF-6D) score, the University of San Diego Shortness of Breath Questionnaire (UCSD-SOBQ), forced vital capacity (FVC), diffusing capacity of the lung for carbon monoxide (DLCO), and six-minute walk distance (6MWD).

The study concluded with the following clinical findings:

1. The FSS questionnaire is a reliable tool for measuring fatigue in patients with Interstitial Lung Disease (ILD).

2. The FSS had high internal consistency, meaning that the questions in the questionnaire were consistently measured the same thing.

3. There was a moderate to strong correlation between the FSS scores and patient-reported anchors, such as the vitality question from the SF-6D and the UCSD SOBQ total score.

4. There was a weak correlation between the FSS scores and physiological measures, such as FVC, % predicted DLCO and 6MWD.

5. Patients using supplemental oxygen, those prescribed steroids, and those with lower %FVC and %DLCO had higher mean FSS scores, indicating greater fatigue.

The findings of the study further support the need for a reliable and valid measure of patient-reported fatigue in ILD. The FSS possesses acceptable performance characteristics for assessing fatigue and distinguishing different levels of fatigue among patients with ILD.

The researchers of the study added that” This research can help healthcare providers to better understand and manage the impact of fatigue on patients with ILD and may inform the development of targeted interventions to improve patient outcomes.”

Reference:

Aronson, K. I., Martin-Schwarze, A. M., Swigris, J. J., Kolenic, G., Krishnan, J. K., Podolanczuk, A. J., Kaner, R. J., Martinez, F. J., Safford, M. M., Pinheiro, L. C., & Pulmonary Fibrosis Foundation (2023). Validity and Reliability of the Fatigue Severity Scale in a Real-World Interstitial Lung Disease Cohort. American journal of respiratory and critical care medicine, 10.1164/rccm.202208-1504OC. Advance online publication. https://doi.org/10.1164/rccm.202208-1504OC