Validation of the SF-6D Health State Utilities Measure in Lower Extremity Sarcoma

Abstract EN

Aim.

Health state utilities measures are preference-weighted patient-reported outcome (PRO) instruments that facilitate comparative effectiveness research.

One such measure, the SF-6D, is generated from the Short Form 36 (SF-36).

This report describes a psychometric evaluation of the SF-6D in a cross-sectional population of lower extremity sarcoma patients.

Methods.

Patients with lower extremity sarcoma from a prospective database who had completed the SF-36 and Toronto Extremity Salvage Score (TESS) were eligible for inclusion.

Computed SF-6D health states were given preference weights based on a prior valuation.

The primary outcome was correlation between the SF-6D and TESS.

Results.

In 63 pairs of surveys in a lower extremity sarcoma population, the mean preference-weighted SF-6D score was 0.59 (95% CI 0.4–0.81).

The distribution of SF-6D scores approximated a normal curve (skewness = 0.11).

There was a positive correlation between the SF-6D and TESS ( r = 0.75 , P < 0.01 ).

Respondents who reported walking aid use had lower SF-6D scores (0.53 versus 0.61, P = 0.03 ).

Five respondents underwent amputation, with lower SF-6D scores that approached significance (0.48 versus 0.6, P = 0.06 ).

Conclusions.

The SF-6D health state utilities measure demonstrated convergent validity without evidence of ceiling or floor effects.

The SF-6D is a health state utilities measure suitable for further research in sarcoma patients.