gms | German Medical Science

Introduction: BMI affects clinical outcomes in patients with RA treated with anti-TNFs [1]. Efficacy of abatacept (ABA) does not seem to be impacted by weight; baseline weight was not identified as a predictive factor of efficacy (DAS28 [CRP] <2.6) in a post hoc analysis of the AVERT trial [2] and, in real-world analyses, BMI did not impact retention rate on drug or effectiveness [3], [4]. Clinical evaluation of RA in obese patients can be difficult, but power Doppler ultrasound (PDUS) can be used to differentiate joint effusion from synovitis and identify real disease activity due to RA. APPRAISE was the first prospective, multinational study to use the composite greyscale/PDUS synovitis score to measure early signs of response to treatment with IV ABA+MTX [5], [6], [7]. We explored the effect of BMI on efficacy of IV ABA+MTX using PDUS.

Methods: PDUS was assessed over 6 months in underweight/normal (<25 kg/m²), overweight (25–<30 kg/m²) and obese (≥30 kg/m²) patients receiving IV ABA+MTX. Efficacy was assessed by the percentage of patients achieving DAS28 (CRP) <2.6, low disease activity (DAS28 [CRP] ≥3.2) or clinically meaningful improvement (change in DAS28 [CRP] ≥1.2).

Results: Of the 96/104 patients evaluable for PDUS, 46 (47.9%) were underweight/normal, 28 (29.2%) were overweight and 22 (22.9%) were obese. Baseline demographics and disease characteristics were comparable between BMI subgroups; however, differences were noted at baseline between global PDUS joint effusion scores within each subgroup: mean (SD) score was 15.7 (15.2) for underweight/normal, 19.6 (16.1) for overweight and 23.0 (16.4) for obese patients. Mean changes from baseline in PDUS and DAS28 (CRP) over 6 months for each subgroup are presented; no differences between subgroups were detected (Figure 1 [Fig. 1]). When using more stringent criteria such as the percentage of patients reaching DAS28 (CRP) <2.6 over time, a greater response within the first month was seen in the underweight/normal group versus overweight and obese groups, influenced mainly by high-sensitivity CRP and patient global assessment; responses were otherwise similar over 6 months.

Conclusion: This post hoc analysis of the APPRAISE study confirms that BMI does not affect clinical response to IV abatacept+MTX, nor does it influence the magnitude in changes of PDUS-detected inflammation over time.

Note: This abstract was first presented at the EULAR Congress, 10–13 June 2015, Rome, Italy (THU0106) and published in the corresponding supplement of Ann Rheum Dis.