Analysis of factors influencing X-ray images of spinal injury in patients with ankylosing spondylitis / 中华风湿病学杂志

ABSTRACT

Objective@#To investigate factors affecting X-ray structure of the spine in patients with ankylosing spondylitis (AS).@*Methods@#A total of 206 AS patients were recruited. Clinical and laboratory parameters in AS patients were recorded in detail. Disease activity index [Bath ankylosing spondylitis disease activity index (BASDAI), ankylosing spondylitis disease activity score (ASDAScrp)], X-ray structural damage index-modified stoke ankylosing spondylitis spine score (mSASSS) and grading results of radiographic examination of sacroiliac joint were calculated. Statistical analysis using Statistical Package form Soci-science(SPSS) 17.0 Chi-square test, rank test, Logistics regression analysis and other statistical methods were used. Differences of mSASSS levels, spine involvement (mSASSS>0) and rates of bone bridge formation were compared between different groups.@*Results@#Incidences of spine involvement (100%) and bone bridge formation(65.2%) in AS patients ≥40 years old were significantly higher than those in AS patients <40 years old (90.6%、31.9%)(χ2=4.651, P=0.031; χ2=16.647, P<0.01), and the level of mSASSS was also higher (Z=5.575, P<0.01). In AS patients with BMI ≥24 kg/m2, disease duration ≥5 years (49.2%, 50.4%), rates of bone bridge formation was significantly higher than those in AS with BMI <24 kg/m2, but the disease duration (34.5%, 19.7%)(χ2=4.014, P=0.045; χ2=18.173, P=0.03), and mSASSS values were significantly higher (Z=2.281, P=0.023, Z=4.828, P<0.01). Bone bridge formation rate in smoking patients (50.6%) was significantly higher than that in non-smoking patients (31.0%) (χ2=7.346, P=0.007) and mSASSS value was significantly higher (Z=2.045, P=0.041). Bone bridge formation rates in AS with high-ESR and high-CRP(48.6%, 49.0%) were significantly higher than those in patients with normal-ESR and normal-CRP(25.6%, 28.9%)(χ2=10.784, P=0.001; χ2=8.102, P=0.004) and mSASSS value was clearly higher(Z=2.379, P<0.01; Z=3.112, P<0.01). Bone bridge formation rate in AS with BASDAI≥4 or ASDAScrp≥2.1 groups (52.8%, 46.4%) were significantly higher than that in AS with BASDAI<4 or ASDAScrp<2.1 groups (34.2%, 30.7%) (χ2=5.681, P=0.017; χ2=4.646, P=0.031) and mSASSS values were significantly higher (Z=3.887, P<0.01; Z=3.895, P=0.004). Rates of bone bridge formation among different X-ray grading of sacroiliac joint (10.8%, 35.6%, 60.3%) and MRI findings (33.3%, 50.0%, 15.4%) differed with each other (χ2=25.714, P<0.01; χ2=6.855, P=0.032). Logistics regression analysis showed that BMI [OR(95%CI)=1.145(1.037, 1.265), P<0.01], disease duration [OR(95%CI)=1.144(1.055, 1.239), P<0.01], smoking [OR(95%CI)=2.832(1.343, 5.969), P<0.01] and sacroiliac joint X-ray staging [OR(95%CI)=2.584(1.337, 4.997), P<0.01] were risk factors for the bone bridge formation in spine of AS.@*Conclusion@#Spinal involvement in AS is related to disease activity. Bone bridge formation correlateswith disease duration, BMI and disease-status, especially with smoking.