Standardizing fatigue measurement in multiple sclerosis: the validity, responsiveness and score interpretation of the PROMIS SF v1.0 – Fatigue (MS) 8a

Abstract

Background: Fatigue is one of the most common and the single most disabling symptom of multiple sclerosis (MS). However, there is a lack of consensus on the most appropriate fatigue measures in clinical practice and research, based upon rigorously validated, generalizable, and publicly available instruments. The objective of this research was to generate additional evidence regarding the validity and applicability of the PROMIS SF v1.0 -Fatigue (MS) 8a, including content validity, reliability, construct validity and responsiveness, as well as to assess minimal important difference (MID) estimates and a score interpretation tool to aide meaningful individual level score interpretation. Methods: A mixed-methods, sequential design was followed. Cognitive debriefing (CD) interviews (n=29) were performed with MS patients, to assess the relevance and comprehensiveness of the PROMIS Fatigue (MS) 8a scores. To evaluate the psychometric properties of the PROMIS Fatigue (MS) 8a, two observational studies were conducted: a cross-sectional study at two US MS centers (n=296), and a 96-week longitudinal study in a UK MS Register cohort (n=384). Main outcomes and measures were estimates of known-groups validity, convergence validity, reliability, and responsiveness, a guide for interpreting PROMIS Fatigue (MS) 8a T-scores, and anchorbased MID estimates. Results: The CD interviews confirmed the comprehensiveness and relevance of the PROMIS Fatigue (MS) 8a in assessing MS fatigue. Cronbach's alpha (>0.9) and intra-class correlation coefficient (≥0.9) for test-retest scores at 5-7 days follow-up, supported strong internal consistency and test-retest reliability. Hypothesized differences were found across patient groups in patient reported fatigue and related concepts (analysis of variance [ANOVA], P <0.001). PROMIS Fatigue (MS) 8a scores were sensitive to bi-directional changes in fatigue (GHS fatigue global question) and physical health (PROMIS GHS GPH), over a 52-week follow-up. Score changes of 3.4-4 points are proposed as MID criteria for minimal improvement or worsening in fatigue.

The validity, responsiveness, and score interpretation of the PROMISnq Physical Function – Multiple Sclerosis 15a short form in multiple sclerosis

“…Detailed description of the two studies and study procedures are published elsewhere (Kamudoni et al, 2021). In the UK-MSR-study, participants completed assessments at baseline, Weeks 1, 24, 52, 72, and 96 via the register's online portal, from September 2018 to October 2020.…”

Blended versus face-to-face cognitive behavioural therapy for severe fatigue in patients with multiple sclerosis: A non-inferiority RCT

“…26 Clinically significant improvement was defined as either a score of < 35 on the CIS subscale fatigue severity, or an improvement of ⩾ 8 points on this subscale. 18 Secondary outcome measures were other fatigue measures (Fatigue Severity Scale and PROMIS-Fatigue Short Form 8a [27][28][29] ), limitations in daily functioning and quality of life (Sickness Impact Profile, Work and Social Adjustment Scale and SF36 [30][31][32][33] ). See Supplement 2 for a description of the psychometric qualities of these questionnaires.…”

“…Secondary outcome measures were other fatigue measures (Fatigue Severity Scale and PROMIS-Fatigue Short Form 8a 27–29 ), limitations in daily functioning and quality of life (Sickness Impact Profile, Work and Social Adjustment Scale and SF36 30–33 ). See Supplement 2 for a description of the psychometric qualities of these questionnaires.…”

Responsiveness and minimal important change of seven PROMIS computerized adaptive tests (CAT) in patients with advanced chronic kidney disease

“…This is the first study examining the responsiveness of PROMIS measures in patients with CKD. The responsiveness of PROMIS measures has been studied in patients with other chronic conditions, such as multiple sclerosis [ 36 ], COPD [ 37 ], chronic low back pain [ 38 ], and rheumatoid arthritis [ 39 ]. These studies also reported low changes in PROMIS (and other PROM) scores, because of relatively short follow-up periods, during which most patients did not change.…”