Validity of the mental health subscale of the SF-36 in persons with spinal cord injury

Abstract

Study design: Cross-sectional study 5 years after discharge from inpatient rehabilitation.

Objective: To examine the psychometric properties of the Mental Health subscale (MHI-5) of the 36-Item Short Form Health Survey (SF-36) in persons with spinal cord injury (SCI).

Setting: Eight Dutch rehabilitation centres with specialised SCI units.

Methods: Possible floor and ceiling effects were assessed, and Cronbach's α coefficient was calculated to assess internal consistency. Concurrent and divergent validity were assessed using Spearman correlations between the MHI-5 and measures of life satisfaction, neuroticism, vitality, general health, functional independence, participation, lesion characteristics and demographics.

Results: There were no floor or ceiling effects, but the total MHI-5 score was slightly skewed (-1.15). Internal consistency was good (α=0.79). Concurrent validity was shown by significant Spearman correlations between the MHI-5 and life satisfaction (0.53), neuroticism (-0.55), vitality (0.53) and general health (0.37). Divergent validity was shown by weak and, in part, non-significant correlations between the MHI-5 and functional independence (0.09), participation (-0.28) and lesion characteristics (range -0.01-0.19).

Conclusion: The MHI-5 showed reliability and validity as a measure of mood in persons with SCI, and is a promising measurement instrument to assess mental health problems in this population.