In the present study we evaluated the impact of baseline
antinuclear antibody (ANA) status and use of
methotrexate on development of
infliximab-related infusion reactions in patients with
rheumatoid arthritis (RA) or
spondylarthropathies (SpAs), including
psoriatic arthritis. All patients with RA (n = 213) or SpA (n = 76) treated with
infliximab during the period 1999-2005 at the Department of Rheumatology in Lund, Sweden were included. ANAs were present in 28% and 25% of RA and SpA patients, respectively. Because of differences in baseline characteristics, we used a binary logistic regression model to calculate odds ratios (
ORs), adjusting for age, sex and
prednisolone dosage. Altogether 21% of patients with RA and 13% of patients with SpA developed infusion reactions (P = 0.126). The OR for development of infusion reactions in RA patients with baseline ANA positivity alone was 2.1.
Infliximab without
methotrexate and
infliximab as monotherapy were associated with
ORs of 3.1 and 3.6, respectively. Combining
infliximab without
methotrexate and ANA positivity yielded an OR for infusion reaction of 4.6. Lower age at disease onset and longer disease duration were associated with infusion reactions (P = 0.012 and P = 0.036, respectively), but age, sex,
C-reactive protein, erythrocyte sedimentation rate, Health Assessment Questionnaire and Disease Activity Score-28 at baseline were not. No predictors of infusions reactions were identified in SpA patients. RA patients treated with
infliximab without
methotrexate, and who are positive at baseline for ANAs are at increased risk for developing
infliximab-related infusion reactions.