Assessment of Patient-Reported Physical Function in Persons With Upper Extremity Amputation: Comparison of Short Form Instruments.

OBJECTIVE

The aim of the study was to compare psychometric properties of the Patient-Reported Outcomes Measurement Information System upper extremity measure (PROMIS UE) 7-item short form with 6- and 13-item versions for persons with upper limb amputation.

DESIGN

The study used a telephone survey of 681 persons with upper limb amputation. Versions were scored two ways: PROMIS health measure scoring (PROMIS UE HMSS) and sample-specific calibration (PROMIS UE AMP). Factor analyses and Rasch analyses evaluated unidimensionality, monotonicity, item fit, differential item functioning, and reliability. Known group validity was compared for all versions.

RESULTS

Model fit was acceptable for PROMIS-6 UE AMP and marginally acceptable for PROMIS-13 UE AMP and PROMIS-7 UE AMP. Item response categories were collapsed because of disordered categories. A total of 91.4% of participants had PROMIS-13 UE AMP scores with reliability greater than 0.8, compared with 70.4% for PROMIS-7 UE AMP, and 72.1% for PROMIS-6 UE AMP versions. No differences were observed by prosthesis use. Scores differed by amputation for all measures except the HMSS scored 13- and 7-item versions.

CONCLUSIONS

The PROMIS-13 UE AMP short form was superior to the health measures scoring system scored PROMIS-7 UE or PROMIS-6 UE, and to the PROMIS-7 UE AMP and PROMIS-6 UE AMP. Issues with known group validation suggest a need for a population-specific measure of upper extremity function for persons with upper limb amputation.