Predictors of treatment resistance in ankylosing spondylitis

Abstract

The study aimed to determine the predictors of treatment resistance in patients with ankylosing spondylitis with a neuropathic component of pain syndrome. We examined 142 patients who were diagnosed with ankylosing spondylitis according to the modified New York criteria. Among the examined patients, 113 (79.6 %) were men, and 29 (20.4 %) were women; the average age was 42±8.8 years, and the duration of the disease was 6.8±3.5 years. The control group consisted of 25 practically healthy individuals (19 men and 6 women) of the same age. It was found that in patients with ankylosing spondylitis with the presence of a neuropathic component of pain syndrome, the level of glial neurotrophic factor (GDNF) was significantly (p<0.05) lower not only compared to the control group: 2,644±1,166 pg/ml vs. 4,959±2,070 pg/ml, but also compared to patients without neuropathic pain: 4.344±2.936 pg/ml (p<0.05). To determine the predictors of resistance to treatment of ankylosing spondylitis, we followed the results of 12 – week treatment of 43 patients who were divided into two groups depending on the content of glial neurotrophic factor (up to 3.0 pg/ml, 21 patients) and with normal GDNF levels (over 3.0 pg/ml, 22 patients) before treatment. The proportion of ASAS20 responders among patients with normal GDNF levels was three times higher than among patients with reduced GDNF levels: 45.5 % vs. 14.3 %, p<0.05. Thus, reduced plasma GDNF levels are associated with a more severe course of the disease, higher activity of the pathological process, poorer functional capacity, quality of life, the state of the affective sphere of patients, and a poorer response to treatment, which allows us to consider reduced levels of glial neurotrophic factor as a predictor of resistance to therapy.