Impact of Site of Care on Infection Rates Among Patients with Primary Immunodeficiency Diseases Receiving Intravenous Immunoglobulin Therapy

Richard L. Wasserman, Diane Ito, Yan Xiong, Xiaolan Ye, Patrick Bonnet, Josephine Li-McLeod

Patients with primary immunodeficiency diseases (PIDD) are at increased risk of infection and may require lifelong immunoglobulin G (IgG) replacement. Infection incidence rates were determined for patients with PIDD receiving intravenously administered IgG (IGIV) in a home or hospital outpatient infusion center (HOIC). Data were extracted from a large, US-based, employer-sponsored administrative database. Patients were eligible for analysis if they had ≥1 inpatient or emergency room claim or ≥2 outpatient claims with a PIDD diagnosis between January 2002 and March 2013, 12 months of continuous health plan enrollment prior to index date (i.e., first IGIV infusion date), and 6 months of continuous IGIV at the same site of care after the index date. Incidences of pneumonia (bacterial or viral) and bronchitis (all types) within 7 days of IGIV infusion were retrospectively determined and compared between sites of care. A total of 1076 patients were included in the analysis; 51 and 49% received IGIV at home and at an HOIC, respectively. The event/patient-year of pneumonia was significantly lower in patients receiving IGIV at home compared to an outpatient hospital (0.102 vs. 0.216, p = 0.0071). Similarly, the event/patient-year of bronchitis was significantly lower among patients infusing at home compared to an HOIC (0.150 vs. 0.288, p < 0.0001). PIDD patients experienced incidence rates for pneumonia and bronchitis that were lower for patients receiving home-based IGIV treatment versus HOIC-based IGIV treatment. The lower infection rates in the home setting suggest that infection risk may be an important factor in site of care selection.