title: Body mass index influences the response to infliximab in ankylosing spondylitis.
abstract: BACKGROUND
  The excess of adipose tissue in obese individuals may have immunomodulating properties and pharmacokinetic consequences. The aim of this study was to determine whether body mass index (BMI) affects response to infliximab (IFX) in ankylosing spondylitis (AS) patients.
  
  
  METHODS
  In 155 patients retrospectively included with active AS, the BMI was calculated before initiation of IFX treatment (5 mg/kg intravenously). After 6 months of treatment, changes from baseline in BASDAI, Visual Analogue Scale (VAS) pain, C-reactive protein (CRP) level, and total dose of nonsteroidal antiinflammatory drug (NSAID) were dichotomized with a threshold corresponding to a decrease of 50% of initial level of the measure, into binary variables assessing response to IFX (BASDAI50, VAS50, CRP50, NSAID50). Whether the BMI was predictive of the response to IFX therapy according to these definitions was assessed with logistic regression.
  
  
  RESULTS
  Multivariate analysis found that a higher BMI was associated with a lower response for BASDAI50 (P = 0.0003; OR, 0.87; 95% CI (0.81 to 0.94)), VAS50 (P < 0.0001; OR, 0.87; 95% CI (0.80 to 0.93)); CRP50 (P = 0.0279; OR, 0.93; 95% CI (0.88 to 0.99)), and NSAID50 (P = 0.0077; OR, 0.91; 95% CI (0.85 to 0.97)), criteria. According to the three WHO BMI categories, similar results were found for BASDAI50 (77.6%, 48.9%, and 26.5%; P < 0.0001), VAS50 (72.6%, 40.4%, and 16.7%; P < 0.0001); CRP50 (87.5%, 65.7%, and 38.5%; P = 0.0001), and NSAID50 (63.2%, 51.5%, and 34.6%; P = 0.06).
  
  
  CONCLUSIONS
  This study provides the first evidence that a high BMI negatively influences the response to IFX in AS. Further prospective studies, including assessment of the fat mass, pharmacokinetics, and adipokines dosages are mandatory to elucidate the role of obesity in AS IFX response.
authors.affiliation: Rheumatology Department, AP-HP, Paris Diderot, Sorbonne Paris Cité University, Bichat Claude Bernard Hospital, 46 rue Henri Huchard, Paris, 75018, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Ottaviani
authors.forename: Yannick
authors.initials: Y
authors.lastname: Allanore
authors.forename: Florence
authors.initials: F
authors.lastname: Tubach
authors.forename: Marine
authors.initials: M
authors.lastname: Forien
authors.forename: Anaïs
authors.initials: A
authors.lastname: Gardette
authors.forename: Blandine
authors.initials: B
authors.lastname: Pasquet
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Palazzo
authors.forename: Marine
authors.initials: M
authors.lastname: Meunier
authors.forename: Gilles
authors.initials: G
authors.lastname: Hayem
authors.forename: Chantal
authors.initials: C
authors.lastname: Job-Deslandre
authors.forename: André
authors.initials: A
authors.lastname: Kahan
authors.forename: Olivier
authors.initials: O
authors.lastname: Meyer
authors.forename: Philippe
authors.initials: P
authors.lastname: Dieudé
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D015992:Body Mass Index; D005260:Female; D006801:Humans; D000069285:Infliximab; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013167:Spondylitis, Ankylosing / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D018501:Antirheumatic Agents; D000069285:Infliximab