Transverse myelitis (TM) is a rare spinal cord inflammatory disorder that can cause paralysis. It can affect both children and adults and can have a variety of causes. Future clinical trials are needed to improve the understanding and treatment of TM, but the outcome data needed to correctly design and power such trials are limited. A prospective study of pediatric TM outcomes at defined time points after symptom onset will provide the necessary information for future interventional trials.
The specific aims of the Collaborative Assessment of Pediatric Transverse Myelitis: Understand, Reveal, Educate (CAPTURE) study were to determine the responses to various treatments for pediatric TM. Furthermore, the study was originally designed to determine which patient-reported outcomes correlated best with clinician-acquired measures. Due to the appearance of a new clinically significant variant of TM, termed acute flaccid myelitis (AFM), post hoc analyses were implemented to understand the impact of treatment on patients diagnosed with AFM.
This was a prospective, nonrandomized, observational trial using data from 2 patient cohorts. The cohorts included 1 group of patients who completed the Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric and/or Parent Proxy short forms at designated time points but did not have in-person evaluations at any of the recruiting centers. The second cohort completed the same patient- and/or parent-reported outcome assessments as cohort 1 but were also examined by clinicians at one of the recruiting centers at designated time points to collect predefined clinical measurements. The in-person cohort had neurologic exams and data that were entered into a Research Electronic Data Capture (REDCap) database. For patients who did not complete in-person examinations, their medical records were reviewed at the University of Texas Southwestern Medical Center and the data abstracted. Patients were followed for up to 12 months from TM onset. Clinically distinct subtypes of TM were identified, and the responses to various therapies were analyzed.
We were unable to adequately assess the planned primary outcome of the study due to underrecruitment but were able to collect several important data sets. All 3 patients (100%) with appropriate available treatment data (ie, those who had Functional Independence Measure for Children [WeeFIM] total scores at onset and 12 months postonset, and were treated with plasma exchange [PLEX] as their first-line therapy at onset) achieved the minimum clinically significant increase in WeeFIM total score of 22 points. Of the 8 patients treated with intravenous immunoglobulin as their first-line therapy at onset, potentially followed by PLEX, 4 (50%) patients achieved the minimum clinically significant increase in WeeFIM total score of 22 points. Those patients treated with PLEX as their first-line therapy did not have an increase in the relative risk of achieving the minimum clinically significant increase in WeeFIM total score compared with those who did not receive PLEX as their first-line therapy ( = .24 by Fisher exact test; 95% CI, 0-4.16 points). Additionally, the PROMIS Parent Proxy Mobility subset and WeeFIM Motor subset were shown to be highly correlated ( = −0.84; 95% CI, −0.91 to −0.74 points; < .0001). Last, the analysis of the sample of patients with AFM yielded information necessary for the understanding of this condition.
Despite its limitations, the CAPTURE study had several important accomplishments. First, we quantified demographics and outcomes of patients with classically described TM and the newly recognized variant, AFM. The data collected in this study justify the need for future prospective trials of therapeutic interventions and allow for the appropriate design and powering of those studies. Finally, this report outlines correlations between the patient-reported PROMIS Mobility scale and the Motor section of the clinician-derived WeeFIM scale, indicating that this patient-reported outcome can be used for observational studies and tracks well with the gold standard of clinician-derived motor function.
This study was limited by underrecruitment and missing data. Because of these limitations, it was not possible to complete the preplanned primary end point analysis.
