Effect of body mass index on treatment response of biologic/targeted-synthetic DMARDs in patients with rheumatoid arthritis, psoriatic arthritis or axial spondyloarthritis. A systematic review

BACKGROUND: Overweight and/or obese patients with inflammatory arthritis (IA) have higher disease activity and lower chances of achieving and/or maintaining the treatment targets. Weight/obesity also appears to negatively affect the response to tumor necrosis factor (TNF) inhibitors in IA patients, including rheumatoid arthritis -RA, psoriatic arthritis -PsA, axial spondyloarthritis -AxSpA. We conducted a systematic literature review (SLR) for the effect of weight/body-mass-index (BMI) in the efficacy of all approved biologic (b) and targeted-synthetic (ts) DMARDs for the treatment of IA.METHODS: For this PROSPERO-registered SLR, we searched PubMed, Scopus and Cohrane-Library from inception up to June 21st 2022. Clinical-trials (randomized and non-randomized) and observational studies of RA, PsA or AxSpA patients that reported the effect of weight/BMI on response (all possible outcomes) to b/ts-DMARDs were included. Risk-of-bias was assessed via RoB2-Cochrane-tool and Newcastle-Ottawa-scale for randomized and non-randomized studies, respectively.FINDINGS: Out of 996 references, 75 eventually fulfilled the inclusion criteria (of which 10 studies were retrieved through manual-search). Among the included studies (TNF-inhibitors: 34, IL-12/23 inhibitors: 4, IL-23 inhibitor: 1, IL-17 inhibitors: 7, tocilizumab: 18, abatacept: 8, rituximab: 3, JAK-inhibitors: 5), most had medium RoB. Efficacy of TNF-inhibitors was affected by BMI in all forms of IA. Data are not robust to compare the effect among various TNF-inhibitors. In contrast, favorable results of IL-23 and IL-17 inhibitors did not appear to be influenced by increased BMI in PsA or AxSpA patients. Similar evidence exists for tocilizumab (in RA) and for abatacept (in RA and PsA), while no conclusion can be drawn for rituximab. More data are needed for JAK-inhibitors, although the effect of weight/BMI does not seem to be significant so far.INTERPRETATION: Weight/BMI should be considered in the treatment-plan of IA patients, with its effect being more pronounced for TNF-inhibitors compared to other b/ts-DMARDs.