Safety and Efficacy of Home-Based Subcutaneous Immunoglobulin G in Elderly Patients with Primary Immunodeficiency Diseases

Background: Subcutaneous immunoglobulin (SCIG) is as effective as intravenous immunoglobulin (IVIG) in minimizing infections in patients with primary immunodeficiency diseases (PIDD) and is associated with fewer systemic adverse events (AEs). Self-infusion/home-based infusion of SCIG improves quality of life and may lower treatment costs compared with hospital or office-based IVIG therapy, but its suitability has not been assessed in elderly patients (>= 65 years). Methods: We conducted a retrospective chart review of 47 elderly patients with PIDD in a single clinical practice in the United States to evaluate the practicality, safety, and efficacy of home-based SCIG infusions in elderly patients with PIDD over a 13-month period. Measurements included baseline disease characteristics, previous and current immunoglobulin G (IgG) replacement regimens, self-administered versus assisted SCIG infusions, SCIG infusion parameters, serum IgG levels, infections, and AEs. Results: Forty-seven of 111 elderly patients (42%) treated with IgG in this practice elected to receive SCIG. All 47 patients received SCIG infusions at home; 39 (83.0%) self-infused the medication. Most patients (n = 46; 98%) received weekly infusions, requiring a mean duration of 65.3 minutes. The mean SCIG dose of 103 mg/kg/week resulted in a mean steady-state serum IgG concentration of 1074 mg/dL. Two patients experienced serious infections on SCIG: an exacerbation of chronic obstructive pulmonary disease/bronchitis, and an abscess. There were no serious systemic AEs. Local injection site reactions, including swelling, redness, burning, or itching, were considered mild or moderate by the patients and resolved within 24 hours. No bruising, bleeding, or skin breakdown occurred, despite concomitant anticoagulant or platelet inhibitor treatment in 45% of patients. Two patients discontinued home-based SCIG, but did not continue any IgG treatment. No patient switched from SCIG to another route of IgG treatment. Conclusions: Home-based SCIG is safe and effective in elderly patients with PIDD, most of whom can self-infuse. Infection rates were low, and no AEs or difficulties in administering SCIG occurred that resulted in treatment discontinuation.