A new method to evaluate hip joint damage in ankylosing spondylitis / 中华风湿病学杂志

ABSTRACT

Objective In order to assess the structure damage of hip joint in ankylosing spondylitis (AS), a new radiograph-based scoring method was developed according to the radiological characteristics of hip involvement in AS, as well referring to prior existing scoring indexes. Methods A new scoring method consti-tuted of erosion, sclerosis and joint space narrowing was developed, pelvis anterior-posterior plain films acquired from patients with AS at baseline and follow-up were collected and assessed by two physicians who were trained in image reading by radiologists. All films were scored independently and blindly. Intra- and inter-reader reliability were assessed by intra-class correlation coefficient (ICC), the feasibility of this new scoring method was assessed by the mean time acquired to score a plain (two hips), its ability to detect the change of structure damage was assessed by the comparison of score differences between baseline and different follow-ups. The date were analyzed by paired-t test or nonparametric tests. Analysis of Variance (ANOVA) or nonparametric tests were utilized for the comparison of means of quantitative variables among the three groups, while Chi-square test for rates of categorical variables. Results No statistically significant differences existed in demographic data and suspected risk factors among the three groups at baseline (P>0.05). Intra-observer reliability was good (0.84 and 0.89), as well as the inter-observer reliability (0.72), the mean time needed to score was (33 ±10) seconds. Score changes were not statistically significant in the groups with follow-up duration of 1-2 and 3-4 years, but in the group of over 5 years, baseline/final scores assessed by the two observers were (6.0±2.7/7.5±3.7) and (5.6±2.1/7.1±3.6), respectively, both changes were statistically significant (t=2.86, Z=-2.99; P<0.01). Conclusion This new method is not only reproducible and easy to operate in clinic practice, but also can tell the changes of hip joint structure damage in the interval of over 5 years, further validation is requeired to demonstrate its discriminability in large populations.