Risk of infection in adult patients with primary immune thrombocytopenia (ITP): a systematic review

ABSTRACT

Introduction

Primary immune thrombocytopenia (ITP) is a bleeding disorder characterized by autoimmune destruction and impaired production of platelets. Immunosuppressive drugs are the main treatment and may increase risk of infection.

Areas covered

This systematic review included studies incorporating adult patients with primary ITP and infectious outcomes. Studies comparing risk of infection with the general population were included as primary and studies without this comparison were considered secondary. Three primary and 10 secondary studies were included. The main findings: 1-year adjusted relative-risk of infection was 4.5 (95% CI, 3.3–6.1) fold elevated compared to the general population. When comparing splenectomized with non-splenectomized ITP patients, the +1-year adjusted relative-risk of infection was 4.0 (95% CI, 2.8–5.6). The unadjusted 5-year mortality rate-ratio for infection-related deaths was 6.0 (95% CI, 3.0–11.8) in one study, and the hazard ratio was 2.4 (95% CI, 1.0–5.7) for fatal infections in another.

Expert opinion

This review emphasizes that patients with ITP have increased risk of infection. Since ITP is a benign hematologic disease, it is important to assess the extent and causes of infection in the clinical care and considerations before initiating treatment. More homogeneous studies are needed on this topic.

KEYWORDS:

• Corticosteroids
• immune thrombocytopenia
• immunosuppression
• infections
• ITP
• mortality
• review
• risk

Article highlights

• Studies in this field are limited and those available are very heterogeneous and therefore difficult to compare.

• Adult patients with primary ITP have increased risk of severe and fatal infection compared to the general population.

• The decision to initiate treatment should be balanced between benefits and potential side-effects, including the risk of infection; therefore, it is important to know the extent of infection among patients with ITP.

• Research suggests that infection is not solely caused by the immunomodulation treatment but may also be a consequence of the autoimmune disease itself.

• The relative contribution to the risk of infection of the autoimmune process on one hand and the immunosuppressive treatment on the other is not yet determined.

Disclosure statement

H Frederiksen has received funding outside of this work from Novartis, Alexion, AbbVie, and Gilead. N Mannering has received funding outside of this work from Novartis. The author(s) have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Author contributions

H Frederiksen and N Mannering conceptualized the idea for the study. All co-authors participated in the study’s design. M Sandvad and EA Pedersen performed the literature search, the screening and wrote the first draft of the article. All authors contributed to writing subsequent drafts. All authors have read and agreed to the submitted version of the manuscript. M Sandvad and EA Pedersen contributed equally and shared co-first authorship.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

The included studies were funded by both private and public foundations. Moulis et al. [39,44] and Portielje et al. [40] did not provide information about funding.