Evidence map›Paper›PMID 41989675›Full record

ArticleJournal of patient-reported outcomes2026

Evaluation of the construct validity of the Michigan Fatigability Index (MIFI) short forms: a cross-sectional survey study.

Anna Kratz, Noelle Carlozzi, Susan Murphy, Tiffany Braley, Daniel Whibley, David Williams, Nora Fritz, Libak Abou, Michael Kallen

Abstract read
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Article in Journal of patient-reported outcomes, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

9 authors.

Anna KratzDepartment of Physical Medicine and Rehabilitation, University of Michigan-Ann Arbor, Ann Arbor, USA. alkratz@umich.edu.
Noelle CarlozziDepartment of Physical Medicine and Rehabilitation, University of Michigan-Ann Arbor, Ann Arbor, USA.
Susan MurphyDepartment of Physical Medicine and Rehabilitation, University of Michigan-Ann Arbor, Ann Arbor, USA.
Tiffany BraleyDepartment of Neurology, University of Michigan-Ann Arbor, Ann Arbor, USA.
Daniel WhibleyDepartment of Physical Medicine and Rehabilitation, University of Michigan-Ann Arbor, Ann Arbor, USA.
David WilliamsDepartment of Anesthesiology, University of Michigan-Ann Arbor, Ann Arbor, USA.
Nora FritzWayne State University, Detroit, USA.
Libak AbouDepartment of Physical Medicine and Rehabilitation, University of Michigan-Ann Arbor, Ann Arbor, USA.
Michael KallenNorthwestern University, Evanston, USA.

Funding

Development of a conceptual model of subjective physical and mental fatigability: the MI-FI studyR21AG053186 · NIA · UNIVERSITY OF MICHIGAN AT ANN ARBOR · PI KRATZ, ANNA LOUISE · 2016 to 2017
$426k
National Multiple Sclerosis Society MB1706-27943NIH HHS R21AG053186
6 · The paper itself

Abstract

backgroundThe Michigan Fatigability Index (MIFI) is a patient reported outcome (PRO) measure that was developed in people with multiple sclerosis (MS) or fibromyalgia (FM). The MIFI consists of three items banks and corresponding 6-item short forms that assess physical fatigability, mental fatigability, or emotional fatigability. This report details examination of convergent and known-groups validity (i.e., construct validity) of the MIFI short forms for MS and FM. METHODOLOGY: A US web-based cross-sectional survey was distributed to n = 2650 participants (FM n = 1242; MS n = 1408) who completed the MIFI measure and measures of fatigue intensity, severity, impact, fatigability, physical and cognitive functioning, anxiety, and depressive symptoms to establish convergent validity. Tests of known groups validity were based on disease severity scores for MS and FM and PROMIS measures of global physical and mental health scores, which were dichotomized into upper and lower tertile health groups.

resultsConvergent validity of the MIFI short forms was supported by moderate to high correlations (r = > 0.60) with measures of similar constructs. Each MIFI fatigability short form was able to distinguish between lower and upper tertiles on global physical and mental health with large effects (η²>0.3), and between lower and upper disease severity subgroups with small to large effects, supporting known groups validity.

conclusionsResults support the construct validity of the MIFI physical fatigability, mental fatigability, and emotional fatigability short forms for MS and FM. The MIFI measures, which are brief and developed specifically for use in clinical populations with high fatigue burden, should be considered for use in clinical and research applications.

Indexed as

FatigueFibromyalgiaMultiple SclerosisPatient Reported Outcome MeasuresAdultCross-Sectional StudiesFemaleHumansMaleMichiganMiddle AgedReproducibility of ResultsSeverity of Illness IndexSurveys and QuestionnairesFatigabilityFibromyalgiaMultiple sclerosisPatient-reported outcomeValidity

Identifiers

PMID41989675
PMCPMC13216400

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