Burden of Infection in Patients With and Without Secondary Immunodeficiency Disease Following Diagnosis of a Mature B Cell Malignancy

Background: This retrospective cohort study compared patient characteristics and burden of infection in patients with mature B cell malignancies with and without secondary immunodeficiency disease (SID). Patients and Methods: Data were extracted from the Humedica database (H-DB) and Guardian Research Network (GRN) database from October 1, 2015 to March 10, 2020, including a 6-month pre-index period (PIP) and 12-month follow-up. Patients aged ≥18 years diagnosed with chronic lymphocytic leukemia/small lymphocytic lymphoma, multiple myeloma, or non-Hodgkin's lymphoma in the PIP were stratified into 2 cohorts: SID (hypogammaglobulinemia [using ICD-10-CM codes] or serum IgG levels <5.0 g/L, both with signs and symptoms of SID or at least 1 infection) and no-SID. Patients with SID or primary immunodeficiency diseases in the PIP were excluded. Results: Overall, 2221 patients with SID (H-DB/GRN: n = 1959/262), and 19,141 patients without SID (n = 17,598/1543) were included. Baseline characteristics were similar across cohorts. At 12-month follow-up, significantly more patients with SID had experienced ≥1 infection and ≥1 severe bacterial infection than those without SID (both P < .001). H-DB/GRN mean (standard deviation) number of severe bacterial infections was 7.6 (9.9)/2.9 (2.7) for the SID cohort versus 5.2 (6.8)/2.4 (2.2) for the no-SID cohort. Conclusion: This study confirms that patients with mature B cell malignancies and SID face a significantly higher burden of infections than those without SID.