ObjectivesTo perform a systematic literature review (SLR) concerning the safety of synthetic (s) and biological (b) disease-modifying anti rheumatic dugs (DMARDs) to inform the 2019 update of the EULAR recommendations for the management of rheumatoid arthritis (RA).MethodsAn SLR of observational studies comparing safety outcomes of any DMARD with another intervention for the management of RA. A comparator group was required for inclusion. For treatments still without registry data (eg, sarilumab and the Janus kinase (JAK) inhibitors baricitinib, upadacitinib), randomised controlled trials (RCTs) and long-term extensions (LTEs) were used. Risk of bias (RoB) was assessed according to standard procedures.ResultsForty-two observational studies fulfilled the inclusion criteria, addressing safety outcomes with bDMARDs and sDMARDs. Nine studies showed no difference in the risk of serious infections across bDMARDs and two studies (high RoB) showed an increased risk with bDMARDs compared with conventional synthetic (cs) DMARDs (adjusted incidence rate ratio 3.1–3.9). The risk of Herpes zoster infection was similar across bDMARDs, but one study showed an increased risk with tofacitinib compared with abatacept (adjusted HR (aHR) 2.0). Five studies showed no increased risk of cancer for bDMARDs compared with csDMARDs. An increased risk of lower intestinal perforation was found for tocilizumab compared with csDMARDs (aHR 4.5) and tumour necrosis factor inhibitor (TNFi) (aHR 2.6–4.0). Sixty manuscripts reported safety data from RCTs/LTEs. Overall, no unexpected safety outcomes were found, except for the possibly increased risk of venous thromboembolism (VTE) with JAK inhibitors.ConclusionData obtained by this SLR confirm the known safety profile of bDMARDs. The risk of VTE in RA, especially in patients on JAK inhibitors, needs further evaluation.