THU0150 Impact of comorbidity burden and obesity on the effectiveness of tocilizumab in patients with rheumatoid arthritis
Authors: D. Pappas, C. Etzel, M. Crabtree, J. Best, S. Zlotnick, J. Kremer
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Few real-world studies have evaluated the impact of comorbidity burden or obesity on the effectiveness of tocilizumab (TCZ) for the improvement of rheumatoid arthritis (RA) disease activity. <h3>Objectives</h3> To compare the effectiveness of TCZ in treating RA in patients with high vs low comorbidity burden and in obese vs nonobese patients in US clinical practice. <h3>Methods</h3> Patients in the Corrona RA registry who initiated TCZ and had follow-up visits at 6 and 12 months after initiation were included. To assess the impact of comorbidity burden on TCZ effectiveness, outcomes were stratified by patients with low Charlson Comorbidity Index (CCI=1) vs high (CCI ≥2). To assess the impact of obesity, outcomes were stratified by patients with BMI &lt;30 (nonobese) vs ≥30 (obese). The primary outcome was mean change in CDAI at 6 and 12 months. Secondary outcomes were mean change in HAQ, the proportions of patients with change ≥the minimum clinically important difference (MCID) in CDAI and HAQ and the proportion who achieved low disease activity (LDA; CDAI≤10). Baseline demographics, clinical characteristics, disease activity and treatment history in the comorbidity and BMI cohorts were compared separately using standardised differences; characteristics with |standardised difference|&gt;0.1 were identified as covariates for inclusion in adjusted comparisons. Outcomes were compared between cohorts using two-sample <i>t</i>-tests or χ<sup>2</sup> tests in unadjusted analyses and linear or logistic regression models to adjust for covariates. <h3>Results</h3> Of 770 patients who initiated TCZ and had CCI data available at baseline (93.8% treated with intravenous [IV] TCZ and 6.2% with subcutaneous [SC] TCZ), 575 (74.7%) had a low CCI and 195 (25.3%) a high CCI. Patients with a high CCI were older (mean [SD] age, 61.5 [12.3] vs 56.9 [13.1] years), were more likely to be obese (52.8% vs 41.7%), had a longer disease duration (mean [SD], 12.8 [9.9] vs 11.6 [8.9] years) and had higher mean (SD) baseline CDAI (25.7 [13.4] vs 23.9 [13.9]) and HAQ (0.71 [0.57] vs 0.57 [0.51]) scores than those with a low CCI. Of the 805 TCZ initiators with BMI data available at baseline (93.9% treated with IV TCZ and 6.1% with SC TCZ), 449 (55.8%) were not obese and 356 (44.2%) were obese. Obese patients were younger (56.7 [12.0] vs 59.0 [13.7] years), had shorter disease duration (11.4 [8.6] vs 12.6 [9.7] years) and had higher baseline CDAI (25.4 [14.3] vs 23.6 [13.4]) and HAQ (0.65 [0.53] vs 0.57 [0.53]) scores than nonobese patients. Patients in all cohorts had improvement from baseline in CDAI at 6 and 12 months, with no significant differences between those with a low vs high CCI or between obese vs nonobese patients (table 1). Secondary outcomes yielded similar results (table 1). <h3>Conclusions</h3> In this real-world analysis, the effectiveness of TCZ for the improvement of RA disease activity was comparable among patients regardless of comorbidity burden or obesity. <h3>Acknowledgements</h3> This study is sponsored by Corrona, LLC. Corrona has been supported through contracted subscriptions in the last 2 years by AbbVie, Amgen, Boehringer Ingelheim, BMS, Celgene, Crescendo, Eli Lilly, Genentech, Gilead, GSK, Horizon Pharma USA, Janssen, Merck, Momenta Pharmaceuticals, Novartis, Pfizer Inc., Roche, UCB and Valeant. <h3>Disclosure of Interest</h3> D. Pappas Grant/research support from: Abbvie, Consultant for: Abbvie, Employee of: Corrona, LLC, C. Etzel Shareholder of: Corrona, LLC, Consultant for: Merck, Employee of: Corrona, LLC, M. Crabtree Employee of: Corrona, LLC, J. Best Shareholder of: Genentech, Inc., Employee of: Genentech, Inc, S. Zlotnick Shareholder of: Genentech, Inc., Employee of: Genentech, Inc, J. Kremer Shareholder of: Corrona, LLC, Consultant for: AbbVie, Amgen, Bristol-Myers Squibb, Eli Lilly and Company, Genentech, GlaxoSmithKline, Pfizer, Regeneron, Sanofi