Psychometric properties of the Spanish Multidimensional Fatigue Inventory in people with heart diseases.

BACKGROUND

Fatigue is one of the most limiting symptoms in individuals with heart disease (HD). However, valid and reliable instruments for assessing fatigue in clinical practice still need to be improved.

OBJECTIVE

To assess the dimensional structure of the self-reported Spanish Multidimensional Fatigue Inventory (MFI) and analyze its psychometric properties in individuals with HD.

METHODS

A longitudinal observational study included 247 participants (age 57.71 years; 23.9 % women; 89.9 % Caucasian). Test-retest reliability was assessed 10-14 days after the first evaluation. Measures evaluating fatigue, health-related quality of life (HRQoL), and functional capacity were collected to assess convergent validity. Acceptability, practicality, construct validity, floor/ceiling effects, internal consistency, and measurement error were also calculated.

RESULTS

Confirmatory factor analysis supported the 4-factor structure of the MFI and the deletion of 3 items for its application in individuals with HD. The 17-item version showed no floor-ceiling effects and exhibited excellent internal consistency (Cronbach's α = 0.90) and test-retest reliability (Intraclass Correlation Coefficient (ICC) = 0.94). While all subscales demonstrated adequate internal consistency (Cronbach's α > 0.70) and good to excellent test-retest reliability (ICC, 0.75 - 0.91), the reduced motivation subscale showed slightly lower internal consistency. The minimal detectable change was 9.5 points for the total score. Convergent validity was established through moderate-strong correlations with fatigue, HRQoL, and functional capacity measures (r = |0.320-0.729|).

CONCLUSIONS

The shortened version of the Spanish MFI (MFI-17) is a valid and reliable tool for quantifying fatigue in individuals with HD, supporting its clinical and research applicability.