Time to initial infusion therapy in Primary Immunodeficiency: A community-based retrospective analysis 2328544

Abstract Introduction Common Variable Immunodeficiency (CVID) and Specific Antibody Deficiency (SAD) require lifelong management to minimize recurrent infections. While immunoglobulin replacement therapy (IgRT) is standard of care, initiation criteria remain heterogeneous. Literature offers conflicting guidance on whether therapy is driven by serological criteria (IgG levels) or clinical manifestation of immune incompetence. This study evaluates the relationship between baseline IgG, clinical encounter frequency, and therapeutic timing. Methods A retrospective analysis was conducted on 26 patients (CVID n = 18; SAD n = 7; undefined n = 1) at a community-based immunology clinic. Variables included baseline serum IgG, unique clinical visits prior to IgRT, and the interval between presentation and first infusion. Non-parametric methods (Spearman correlation, Mann-Whitney U, Kruskal-Wallis) were employed due to non-normal distribution. Results The cohort was predominantly female (84.6%, n = 22) and geriatric. Mean baseline IgG was 619 ± 165 mg/dL; mean interval to therapy was 210 ± 159 days (median: 171). No significant correlation existed between baseline IgG and time to IgRT (r=-0.15, p = 0.478), indicating hypogammaglobulinemia severity did not predict urgency. Conversely, a significant positive correlation was observed between unique clinic visits and time to infusion (r = 0.56, p = 0.004), suggesting patients with complex clinical courses experienced longer delays. No significant differences occurred based on therapy type, age, or sex. Subcutaneous immunoglobulin (92.3%) and home infusion (96.2%) were preferred. Cost concerns (30.8%) and prophylactic antibiotic preference (11.5%) contributed to delays. Conclusion Baseline IgG levels did not correlate with IgRT timing, while clinic visits were significantly associated with longer delays. Findings suggest clinical complexity influences timelines more than serologic thresholds, reflecting management reactive to accumulating encounters rather than driven by serologic criteria. Funding Source GC Biopharma Topic Categories Translational and Interventional Immunology (TI)