Introduction: Despite the therapeutic effectiveness of biologics targeting immune cells or cytokines in patients with inflammatory arthritis, which reflects their pathogenic roles, an increased infection risk is observed in those undergoing biological treatment. However, there are limited data regarding the comparison of infection risks in inflammatory arthritis patients treated with non-biologics (csDMARDs), biologics (bDMARDs), including tumor necrosis factor (TNF) inhibitors and non-TNF inhibitors, or targeted synthetic (ts)DMARDs.Areas covered: Through a review of English-language literature as of 30 June 2019, we focus on the existing evidence on the risk of infections caused by bacteria, Mycobacterium tuberculosis, and hepatitis virus in inflammatory arthritis patients undergoing treatment with csDMARDs, bDMARDs, or tsDMARDs.Expert opinion: While the risks of bacterial and mycobacterial infection are increased in arthritis patients treated with csDMARDs, the risks are further higher in those receiving bDMARDs therapy, particularly TNF inhibitors. Regarding HBV infection, antiviral therapy may effectively prevent HBV reactivation in patients receiving bDMARDs, especially rituximab. However, more data are needed to establish effective preventive strategies for HBsAg-negative/HBcAb-positive patients. It seems safe to use cyclosporine and TNF inhibitors in patients with HCV infection, while those undergoing rituximab therapies should be frequently monitored for HCV activity.Abbreviations: ABT: abatacept; ADA: adalimumab; AS: ankylosing spondylitis; bDMARDs: biologic disease-modifying anti-rheumatic drugs; CKD: chronic kidney disease; COPD: chronic obstructive pulmonary disease; CS: corticosteroids; CsA: cyclosporine A; csDMARDs: conventional synthetic disease-modifying anti-rheumatic drugs; CZP: certolizumab; DAAs: direct-acting antiviral agents; DM: diabetes mellitus; DOT: directly observed therapy; EIN: Emerging Infections Network; ETN: etanercept; GOL: golimumab; GPRD: General Practice Research Database; HBV: hepatitis B virus; HBVr: HBV reactivation; HBsAg+: HBsAg-positive; HBsAg-/anti-HBc+: HBsAg-negative anti-HBc antibodies-positive; HCV: hepatitis C virus; HCQ: hydroxychloroquine: IFX: infliximab; IL-6: interleukin-6; JAK: Janus kinase; LEF: leflunomide; LTBI: latent tuberculosis infection; mAb: monoclonal antibody; MTX: methotrexate; OR: odds ratio; PsA: psoriatic arthritis; PMS: post-marketing surveillance; RA: rheumatoid arthritis; TNF: tumor necrosis factor; TNFi: tumor necrosis factor inhibitor; SCK: secukinumab; SSZ: sulfasalazine; TOZ: tocilizumab; RCT: randomized controlled trial; RR: relative risk; RTX: rituximab; 3HP: 3-month once-weekly isoniazid plus rifapentine; TB: tuberculosis; tsDMARDs: targeted synthetic disease-modifying anti-rheumatic drugs; UTK: ustekinumab; WHO: World Health Organization.
Keywords: Infection risk; biologics; inflammatory arthritis; non-biologics; treatment.