Subcutaneous immunoglobulin in primary immunodeficiency – impact of training and infusion characteristics on patient-reported outcomes

BACKGROUND: Subcutaneous immunoglobulin (SCIG) is increasingly utilized in primary immunodeficiency (PI). Understanding factors associated with treatment experience and satisfaction can optimize patient outcomes. We analyzed Immune Deficiency Foundation (IDF) survey data to evaluate patient-reported outcomes (PROs) in relation to SCIG training and infusion characteristics. Respondents’ PRO scores were rank ordered into ‘best’, ‘intermediate’, and ‘worst’ tertiles. Predicted probabilities of being in the best tertile with any combination of characteristics were generated for each PRO. RESULTS: In 366 SCIG respondents, higher odds of being in the best PRO tertile were driven by favorable training characteristics (particularly, higher confidence post-training and no training barriers) and efficient infusions (infusion preparation ≤20 min and actual infusion < 2 h). Age (≤17 years old) and treatment experience (> 2 years) increased the odds of being in the best tertiles. Compared with the least favorable training/infusion characteristics, those with the most favorable training/infusion characteristics had higher predicted probabilities of being in the best tertiles: TSQM side effects, 59% vs 4%; convenience, 52% vs 4%; effectiveness, 27% vs 13%; global, 26% vs 3%; PROMIS Fatigue, 44% vs 18%. CONCLUSIONS: Increased experience with SCIG consistently improved PROs, but our findings predicted that enhanced training and infusion characteristics improve patient treatment satisfaction beyond that achieved by experience alone.