Therapeutic Plasma Exchange in Pediatric Patients: A Multi-Institutional Landscape Analysis.

Pediatric evidence for therapeutic plasma exchange (TPE) is largely small, single-center cohorts; there is no prior large-scale age-stratified outcomes assessment. Using the TriNetX US Collaborative Network, we identified 3744 patients ≤ 17 years old undergoing an index TPE procedure, stratified into four age groups (≤ 1, 2-5, 6-12, and 13-17 years). ICD-10-CM diagnosis codes recorded 30 days prior to the index procedure were mapped to American Society for Apheresis Categories I-III indications; three high-prevalence nonspecific codes were tracked separately. All-cause mortality at 30 days, 90 days, and 1 year was assessed. All-cause mortality decreased with increasing age at every time window: 30-day mortality ranged from 16.8% (≤ 1 year) to 4.3% (13-17 years, p < 0.0001). Infant mortality risk was concentrated disproportionately in the first 90 days postprocedure. Sex distribution shifted from a slight male predominance in infancy and early childhood (55%-56% male) to a female predominance in adolescence (55% female, p < 0.0001). Leading specific indications were autoimmune encephalitis (10%), sepsis with multiorgan failure (9%), renal transplant rejection (6%), acute disseminated encephalomyelitis (5%), Guillain-Barré syndrome (5%), and myasthenia gravis (4%); nonspecific diagnosis codes were each individually more prevalent than any single ASFA-mapped indication. This is the first large-scale, age-stratified, multi-institutional characterization of pediatric TPE. We identified an inverse relationship between age and all-cause mortality, a sex-distribution shift in adolescence, and an indication landscape dominated by nonspecific diagnosis codes. These findings offer age-stratified benchmarks for clinical counseling and hypothesis generation.