Interventions to reduce infections in patients with hematological malignancies: a systematic review and meta-analysis

Acquired hypogammaglobulinemia is common in chronic lymphocytic leukemia (CLL), non-Hodgkin lymphoma (NHL), and multiple myeloma (MM). No previous systematic reviews (SRs) have compared different approaches to infection prevention. We sought to assess the efficacy and safety of prophylactic immunoglobulin, antibiotics, and vaccination in these patients. We performed an SR and meta-analysis of randomized controlled trials (RCTs) evaluating the efficacy and safety of prophylactic immunoglobulin, antibiotics, and vaccination in adult patients with hematological malignancies commonly associated with acquired hypogammaglobulinemia, specifically, CLL, NHL, and MM. We searched PubMed (MEDLINE), EMBASE, and Cochrane Registry up to 9 January 2021. Results for dichotomous data were expressed as relative risk (RR) with 95% confidence interval (CI) and pooled in a random-effects model. This review was registered with PROSPERO CRD42017070825. From 10 576 studies screened, there were 21 completed RCTs and 1 ongoing. Of these, 8 evaluated prophylactic immunoglobulin (n = 370; 7 published before 2000), 5 evaluated prophylactic antibiotics (n = 1587), 7 evaluated vaccination (n = 3996), and 1 compared immunoglobulin to antibiotics (n = 60). Prophylactic immunoglobulin reduced the risk of clinically documented infection (CDI) by 28% (n = 2 trials; RR, 0.72; 95% CI, 0.54-0.96), and vaccination reduced the risk by 63% (RR, 0.37; 95% CI, 0.30-0.45). Prophylactic antibiotics did not reduce the risk. No intervention reduced all-cause mortality. Prophylactic immunoglobulin and antibiotics increased the risk of adverse events. Findings should be interpreted with caution, given the high risk of bias in many studies. There is a clear need for high-quality contemporary trials to establish the effectiveness of different approaches to preventing infection.