Background Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease that affects the axial skeleton and characterized by pain, stiffness and fatigue [4]. One of the frequent concomitant condition in patients with AS is fibromyalgia (FM). FM shares some common symptoms with AS. According to the many reports concomitant FM in patients with AS has been found in 5.7 - 41.3% cases [1, 2, 3, 5]. Due to the fact that pain is a major component of the disease activity scores of the AS (Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS)), concomitant FM can significantly modify the disease activity in patients with AS.

Objectives The aim of this study was to evaluate the effect of FM on disease activity in patients with AS.

Methods Diagnosis of AS was identified according to the modified New York criteria (1984). FM was diagnosed by ACR criteria (1990). Disease activity was assessed by BASDAI and ASDAS.

Results 80 patients with AS were included into study (15 females and 65 males), age (M ± SD) 41.64±11.4 years. Nineteen patients (23.8%) met the criteria for FM. Patients with AS and AS+FM were representative for age and disease duration. In both groups, ESR (37.7±18.8 and 39.00±19.6 mm/h) was comparable, while ASDAS and BASDAI were significantly different. The disease activity according to both scores was higher in patients with AS+FM. According to the BASDAI in patients with AS disease activity was 5.20±1.4 whereas in patients with AS and FM - 7.14±1.7; according to the ASDAS-ESR difference in disease activity was slightly lower, but remained significant (3.6±0.8 vs 4.2±0.9).

Conclusions The obtained data indicates that concomitant FM is a frequent condition in patients with AS. Presence of FM in patients with AS significantly modifies the disease activity determined by ASDAS. The ASDAS-ESR is more appropriate for determining the disease activity comparing to BASDAI, because included in calculation ESR diminish the distorting effect of FM.

References

1. Fibromyalgia in patients with axial spondyloarthritis: epidemiological profile and effect on measures of disease activity/Fausto Salaffi, Rossella De Angelis, Marina Carottiet al. Rheumatology International 2014;1103–1110.

2. Occurrence of fibromyalgia in patients with ankylosing spondylitis. /ValderilioFeijό Azevedo, Eduardo dos Santos Paiva, Lúcio Ricardo HiurkoFelippe, Ranieri Amorim Moreira. Bras J Rheumatol 2010;50:646–654.

3. Ankylosing spondylitis functional and activity indices in clinical practice. Popescu C, Trandafir M, Bădică AM et al. Journal of Medicine and Life 2014:78–83.

4. Global prevalence of ankylosing spondylitis. Linda E. Dean, Gareth T. Jones, Alan G. MacDonald et al. Rheumatology 2014;53:650–657.

5. Prevalence of fibromyalgia in patients with ankylosing spondylitis Medical Journal of Dr. D.Y. Patil University 2014:338–341.

References

Disclosure of Interest None declared