Six patient-reported outcome measurement information system short form measures have negligible age- or diagnosis-related differential item functioning in individuals with disabilities.

OBJECTIVE

To evaluate the measurement invariance of 6 self-report measures selected for an ongoing longitudinal study of individuals with spinal cord injury, muscular dystrophy, postpolio syndrome, and multiple sclerosis.

DESIGN

Participants completed and returned by mail surveys that included the targeted self-report measures. Ordinal logistic regressions methods were applied to evaluate items for differential item functioning (DIF) by diagnosis and age range.

SETTING

Community.

PARTICIPANTS

Participants (N=2479) who had 1 of the 4 target diagnoses.

INTERVENTIONS: None.

MAIN OUTCOME MEASURES: Six short-form measures from the Patient-Reported Outcome Measurement Information System (PROMIS) were administered to participants to measure fatigue, pain interference, satisfaction with social roles, sleep disturbance, sleep-related impairment, and depression.

RESULTS

One item of 1 measure (fatigue) exhibited DIF by diagnosis based on a published standard for meaningful DIF. However, scores corrected for this DIF were highly correlated with uncorrected scores (r>.999). No DIF by age range was found for any of the measures.

CONCLUSIONS

Study findings support the use of the selected PROMIS short forms for comparing symptoms and quality of life indicators across different diagnoses and age ranges.