Systematic review of fatigue assessment instruments for systemic lupus erythematosus: psychometric validation with COSMIN 2.0 Guidelines

OBJECTIVE: To identify and evaluate the methodological quality and psychometric properties of patient-reported outcome measures (PROMs) for fatigue assessment in systemic lupus erythematosus (SLE) patients. METHODS: A systematic search was performed across eight databases (PubMed, EMBASE, Web of Science, CINAHL, CNKI, WanFang, VIP, SinoMed) from inception to June 12, 2026. Eligible studies focused on developing/psychometrically validating SLE fatigue-specific PROMs with explicit reporting of at least one psychometric property. Study methodological quality and PROM psychometric performance were assessed in accordance with COSMIN 2.0 guidelines; measurement property evidence for each PROM was synthesized across eligible studies, and evidence certainty evaluated via a modified Grading of Recommendations Assessment, Development and Evaluation(GRADE)system. RESULTS: Fifteen studies involving six distinct PROMs were included. No instrument was conclusively recommendable for clinical practice/research due to insufficient high-certainty evidence, particularly for cross-cultural validity/measurement invariance and criterion validity. The Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) was the most promising, with high-quality evidence for five core psychometric properties (content validity, structural validity, internal consistency, construct validity hypothesis testing, responsiveness), and it assesses physical/mental fatigue and their impacts on functional status and daily living. CONCLUSIONS: A critical gap exists in fully validated, high-quality SLE-specific PROMs for fatigue assessment. FACIT-Fatigue is the most viable tool for this population but requires further rigorous psychometric validation. Future research should prioritize comprehensive validation of FACIT-Fatigue (e.g., supplementing cross-cultural and criterion validity evidence) and the development/validation of SLE-specific PROMs to quantify fatigue and its disease-specific manifestations. SYSTEMATIC REVIEW REGISTRATION: PROSPERO (CRD420251272840).