A quick assessment of reliable change in fatigue: Reliable change indices of the modified fatigue impact scale - 5 item (MFIS-5).

BACKGROUND: Reliably monitoring changes in fatigue is an ongoing concern. OBJECTIVE: Evaluate reliable change using the Modified Fatigue Impact Scale 5-item version (MFIS-5) in people with MS (PwMS). METHODS: The MFIS-5 was administered at three time points in 157 PwMS. Test-retest reliability and reliable change scores were calculated at the 0.70, 0.80, 0.90, and 0.95 confidence intervals. RESULTS: Difference scores of 3, 4, 5, and 6 represent statistically meaningful change at the 0.70, 0.80, 0.90, and 0.95 confidence intervals, respectively. CONCLUSION: Cut points derived from this study and prior work can help reliably assess changes in fatigue over time.