Concurrent Validity of PROMIS and LD-SRS Scores in Pediatric Patients With Lower Limb Differences.

BACKGROUND: We sought to assess the concurrent validity of select Patient Reported Outcomes Measurement Information System (PROMIS) domains and Limb Deformity-Scoliosis Research Society (LD-SRS) scores.

METHODS: We prospectively administered PROMIS-25 (including anxiety, depression, fatigue, pain interference, peer relationships, and physical function) and LD-SRS questionnaires to 46 consecutive pediatric patients with lower limb differences, presenting to a single surgeon for reconstruction. Concurrent validity between various subdomains of the 2 outcome measures was assessed through Pearson's correlation, with significance defined as P <0.05. The strength of correlation was interpreted by Evans criteria: absolute r value <0.20 indicating very weak correlation; 0.20 to 0.39, weak; 0.40 to 0.59, moderate; 0.60 to 0.79, strong; and 0.8 or greater indicating very strong correlation.

RESULTS: The LD-SRS Pain, Function, and Mental Health domains most strongly correlated with the PROMIS pain interference (r=-0.79, P<0.001), physical function (r=0.74, P<0.001), and anxiety (r=-0.68, P <0.001) domains, respectively. In addition, LD-SRS pain strongly correlated with PROMIS physical function (r=0.61, P<0.001) and LD-SRS function with PROMIS pain interference (r=-0.72, P<0.001). All PROMIS domains significantly correlated with total LD-SRS scores. PROMIS pain interference (r=-0.79, P <0.001), physical function (r=0.67, P <0.001), and fatigue (r=-0.60, P <0.001) domains demonstrated the strongest correlations with the total LD-SRS score.

CONCLUSIONS: The significant concurrent validity between LD-SRS and multiple PROMIS domains suggests considerable overlap, and perhaps redundancy, between these 2 outcome measures. Given the high degree of concordance and the advantage of computer adaptive testing (CAT) in mitigating administrative burden and survey fatigue, along with the ability to compare outcomes across a wider group of children with a variety of underlying diagnoses, select PROMIS domains may be a viable alternative to LD-SRS score for assessing patient-reported outcomes when treating pediatric patients with lower limb deformities. A larger, multi-center study including pediatric patients with lower limb differences from a diverse background, including age, etiology, native language, and ethnicity, would be helpful to externally validate our findings.

LEVEL OF EVIDENCE: Level-I.