Validity of the short musculoskeletal function assessment questionnaire in patients with a spine fracture
Simon Blixt1,2, Sebastian Mukka3, Peter Försth4
1Department of Clinical Science Intervention and Technology, Karolinska Institutet, K54, SE 141 86, Stockholm, Sweden. simon.blixt@ki.se.
Purpose:
The aim of this study was to validate the use of the Short Musculoskeletal Function Assessment (SMFA) questionnaire in patients with a spine fracture.
Methods:
Cross-sectional cohort of individuals that had sustained a spine fracture (C1-L5) one year earlier. Patients were asked to fill out SMFA, Oswestry Disability Index (ODI), EQ-5D-3L and EQ-VAS. Spearman's rank correlation coefficient (rho) was used to assess convergent validity for each patient-reported outcome measure (PROM). Bland-Altman plots were used to assess PROM agreement.
Results:
82 patients completed all questionnaires. The correlations between SMFA Dysfunction and Bother indices and ODI were 0.89 and 0.86, with EQ-5D-3L index 0.89 and 0.80, and with EQ-VAS 0.80 and 0.73, respectively. The correlation for separate categories of the SMFA dysfunction index (daily activities, emotional status, arm and hand function, mobility) ranged between 0.71-0.87 for ODI, 0.72-0.84 for EQ-5D-3L index, and 0.67-0.77 for EQ-VAS. A selection of the ten items of SMFA that had the highest correlations with ODI resulted in a correlation of 0.91. The agreements between SMFA indices and ODI in Bland-Altman plots were good with small differential biases and minimal proportional biases, but worse for SMFA and EQ-5D-3L index and EQ-VAS.
Conclusion:
The SMFA indices are highly correlated with ODI in patients with a spine fracture. The Dysfunction index and Bother index, or selected SMFA items, may be used to assess outcome in patients with spine fractures as an alternative to ODI.
