Frequency of anemia of inflammation in patients with ankylosing spondylitis requiring anti-TNFα drugs and therapy-induced changes.

OBJECTIVE

Primary: to evaluate the frequency of anemia of inflammation (AOI) in a clinical series of patients with ankylosing spondylitis (AS) requiring anti-TNF (tumor necrosis factor) agents. Secondary: to examine anti-TNF therapy-induced changes in AOI.

METHOD

Prospective, follow-up, 6-month study of all consecutive, new patients with AS requiring anti-TNFα drugs observed between January 2004 and December 2008. AOI was defined according to WHO criteria.

PRIMARY OUTCOME MEASURE

the proportion of patients showing AOI at baseline.

SECONDARY OUTCOME MEASURES

the proportion of patients achieving resolution of AOI at the 6-month visit; the proportion of patients achieving any improvement in haemoglobin (Hb); the proportion of patients with any improvement in blood results.

RESULTS

One hundred and six patients (42 women and 64 men; mean age: 46 years) with AS were evaluated. Sixteen of these (15%) presented with AOI at baseline. After 6 months therapy 13 patients (81%) resolved AOI while two presented an Hb level reduction. After 6 months therapy we did not find a significant statistical improvement in red blood cell numbers (P = 0.85) and transferrin (P = 0.08) levels. Hb, mean corpuscular volume (MCV), iron, ferritin, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) improved reaching statistical significance (P = 0.0002, 0.0001, 0.001, 0.014; 0.007, 0.004, respectively).

CONCLUSION

We found 15% frequency of AOI among a selected series of patients with AS. After 6 months of anti-TNFα therapy AOI resolved in the majority of patients with significant improvement of Hb, MCV, CRP and ESR levels.