RABBIT risk score and ICU admission due to infection in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) patients are at increased risk of infection. Aim of the present study was to investigate whether RA patients admitted to an intensive care unit (ICU) due to infection have higher Rheumatoid Arthritis Observation of Biologic Therapy (RABBIT) risk scores compared to control RA patients. Seventy-four RA patients (32.4% male) admitted to an ICU due to infection (from January 2002 to December 2013) and 74 frequency-matched control RA patients (16.2% male) were included in this cross-sectional study. There was strong evidence for a higher RABBIT risk score in ICU patients (median 2.0; IQR 1.3-3.2) as compared to controls (1.3; IQR 0.8-2.0; p < 0.0001). Traditional disease-modifying anti-rheumatic drugs (DMARDs) (82.4 vs 64.9%; p = 0.015) and biological DMARDs (28.4 vs 14.9%; p = 0.012) were more frequently given to RA patients without ICU admission. Glucocorticoid users were more frequently found in the ICU group (51.4 vs 31.1%; p = 0.012). In a multivariable analysis tDMARD use was associated with lower (OR 0.38; 95% CI 0.15-0.93; p = 0.034) and glucocorticoid use with borderline higher odds of ICU admission (OR 2.05; 95% CI 0.92-4.58; p = 0.078). Chronic obstructive pulmonary disease (OR 2.89; 95% CI 1.10-7.54; p = 0.03), chronic kidney disease (OR 16.08; 95% CI 2.00-129.48; p = 0.009), and age category (OR 2.67; 95% CI 1.46-4.87; p = 0.001) were strongly associated with ICU admission. There was a strong trend towards higher odds of ICU admission with increasing RABBIT risk score. Use of tDMARDs was associated with lower odds of ICU admission. In an adjusted analysis, bDMARDs were not associated with ICU admission. COPD, CKD, and age were strong risk factors for ICU admission.