The Validity of Patient-reported Outcome Measurement Information System (PROMIS) Parent Proxy Instruments to Assess Function in Children With Talipes Equinovarus.

BACKGROUND

Idiopathic talipes equinovarus (ITEV) is a prevalent structural deformity of the foot and ankle in children. The disease-specific instrument (DSI) has commonly been used as an outcomes metric in these patients. The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed to examine the quality of life across various medical conditions. PROMIS has been validated for multiple conditions; however, no studies have evaluated the use of the PROMIS in children with ITEV.

METHODS

A prospective analysis was performed whereby the 2 questionnaires were mailed out to the parents of 91 patients, aged 5 to 17 years, with ITEV. Construct validity of the PROMIS Parent Proxy Profile short forms version was assessed by comparing its domains of Mobility, Fatigue, Pain Interference, and Pain Intensity to the DSI Function domain and PROMIS domains of Anxiety, Depressive Symptoms, Peer Relationships, and Pain Intensity to DSI Satisfaction domain.

RESULTS

Thirty-one complete responses (34% response rate) were returned. The patients' current mean age was 8.8 years, 7 were female individuals, and 12 had unilateral ITEV. Bivariate correlation analysis, using Spearman correlation coefficients, demonstrated a moderate positive correlation between the DSI Function domain and the PROMIS Mobility domain (rs=0.52) and a moderate negative correlation between the DSI Function domain and the PROMIS Pain Interference domain (rs=-0.56), as well as the PROMIS Pain Intensity domain (rs=-0.75). A fair negative correlation (rs=-0.38) with PROMIS Fatigue domain was found. Correlations between the DSI Satisfaction domain and the PROMIS domains were fair or had little relationship.

CONCLUSIONS

These results provide support for the validity of the PROMIS Mobility, Pain Interference, and Pain Intensity domains in this population, however there are no items in PROMIS that can assess overall satisfaction, as with the DSI.

LEVEL OF EVIDENCE: Level II-prospective comparative study.