ABSTRACT
Objective:To predict the inflammatory activity of patients with ankylosing spondylitis (AS) after 12 weeks treatment with recombinant human tumor necrosis factor-α receptor Ⅱ immunoglobulinG Fc fusion protein (rhTNFR:Fc) by Doppler ultrasonography at baseline.Methods:A total of 60 patients with AS were selected, and their general clinical characteristics before and after treatment were compared. Meanwhile, Doppler ultrasonography of the sacroiliac joint was performed to compare the Doppler parameters before and after treatment, and the correlation between baseline Doppler ultrasonography and clinical characteristics was analyzed, along with its diagnostic performance. The pre-treatment and post-treatment parameters were compared to the measured data followed by paired t-test for normal distribution, and the counting data were paired with Chi- square test. Pearson correlation test was used to analyze the correlation between pretreatment ultrasound parameters and pre-treatment disease activity. All statistical tests were bilateral, with a statistically significant difference of P<0.05. Results:After treatment, the overall score [(1.4±1.0) points vs (6.0±1.8) points, t=17.80, P<0.001], night pain score [(1.6±1.2) points vs (5.7±1.5) points, t=15.80, P<0.001], back pain score [(1.9±1.3) points vs (5.5±1.2) points, t=16.39, P<0.001], morning stiffness [(12±6) min vs (38±21) min points, t=8.93, P<0.001], Bath ankylosing spondylitis disease activity index (BASDAI) [(1.1±0.6) vs (4.6±1.3), t=12.41, P<0.001], ankylosing spondylitis disease activity score-C-reactive protein (ASDAS-CRP) [(1.0±0.4) points vs (3.7±0.9) points, t=22.01, P<0.001] and ASDAS-erythrocyte sedimentation rate (ESR) [(1.0±0.7) points vs (4.0±0.8) points, t=20.10, P<0.001] of patients with ankylosing spondylitis were lower than those before treatment, and the differences were statistically significant ( P<0.001). Compared with AS patients before treatment, the color blood flow grading score was significantly lower after treatment [(1.7±0.8) points vs (3.9±1.1) points, t= 12.86, P<0.001). The post-treatment proportion of AS patients with bilateral sacroiliac joint blood flow signal was 67% (40/60), which was lower than 87% (52/60) before treatment, but the difference was not statistically significant ( P=0.251). After treatment, the peak systolic velocity (PSV), pulsatile index (PI) and resistance index (RI) were significantly higher than those before treatment [(30±17) cm/s vs (19±8) cm/s, t=-5.42, P<0.001; (1.55±0.69) vs (1.00±0.45), t=0.45, P<0.001; (0.81±0.11) vs (0.55±0.14), t=11.20, P<0.001)]. The end diastolic velocity (EDV) before and after treatment had no statistical significant differences [(6.7±2.5) cm/s vs (6.3±1.9) cm/s, t=0.80, P=0.428]. Baseline Doppler ultrasound parameters and pre-treatment clinical indicators showed that PI and RI were negatively correlated with BASDAI ( r=-0.49, P=0.005; r=-0.51, P<0.001) , and blood flow grades were positively correlated with BASDAI ( r=0.46, P=0.028). However, there were no significant correlation between PSV, EDV and BASDAI ( r=-0.12, P=0.176; r=0.03, P=0.756). Baseline Doppler ultrasound parameters were correlated with ASDAS-CRP ( r=-0.45, P=0.012; r=0.29, P<0.048; r=-0.52, P<0.035; r=-0.76, P<0.001; r=0.61, P<0.001). There was no correlation between EDV and ASDAS-ESR ( r=0.30, P=0.110), the other ultrasound Doppler parameters were correlated with ASDAS-ESR ( r=-0.36, P<0.001; r=-0.54, P<0.001; r=-0.61, P=0.021; r=0.41, P=0.028). The receiver operating characteristic curve was drawn with the baseline RI value as a variable. According to the ASDAS-CRP value, the diagnostic threshold for determining the presence or absence of AS activity after 12 weeks of treatment was 0.49, with an area under the curve of 0.817, sensitivity of 88.1%, specificity of 61.1%, positive predictive value of 66.7%, and negative predictive value of 86.1%. Conclusion:Baseline Doppler ultrasound correlates well with clinical indicators, among which baseline RI values is a good predictor of inflammatory activity status after rhTNFR:Fc treatment.