Background Spinal ankylosis is most important reason of functional impairment in ankylosing spondylitis (AS). In routine practice, all patients who learned diseases's name ask ankylosing posture and risk factors for ankylosis. Thus, risk factors of ankylosing posture is a priority for patient perspective.
Objectives Objective of this study was to assess risk factors of advanced spinal ankylosis in patients with AS during biological treatment.
Methods HÜR-BİO (Hacettepe University Rheumatology Biologic Registry) is a single center biological registry since 2005 in Turkey. Here, patients analysed were AS patients treated with TNFi. Data collected includes demographic data, co-morbidities, smoking, baseline and follow-up disease activity parameters (such as BASDAI, BASFI, CRP, ESR, global VAS). There are 630 AS patients with TNFi in this database. Available digital radiographic imaging of lumbar spine radiographies were reassesed for spinal ankylosis by a physician (UK). Two intervertebral adjacet bridges and/or fusion at the lumbar spine defined advanced spinal disease (1), and typical bamboo view defined as bamboo spine. Univariate and multivariate analysis were performed to determine risk factors in advanced spinal ankylosis.
Results In all, 530 (65.9% male) patients were analyzed. Mean age was 41±11 years old, mean disease duration was 9.7±7.2 years. Mean TNFi duration was 37±30 months. At least one syndesmophyte was found in 248 (46.8%); 99 (18.7%) patients had advanced spinal ankylosis (60 bamboo spine, 39 advanced spinal disease). Patients with advanced spinal ankylosis were older (51±9 vs 39±10 p<0.001), had a longer disease duration (16±9 vs 8±6 years, p<0.001), were more frequently male (84/99 (84.8%) vs 263/431 (61.0%), p<0.001), with higher weight (79±13 vs 74±14 kilogram, p=0.002), more radiological hip involvement (39/91 (42.8%) vs 54/376 (14.3%), p<0.001), severe hip involvement (17/91 (18.7%) vs 25/376 (6.6%), p<0.001), more frequently uveitis (17/80 (21.2%) vs 37/329 (11.2%), p=0.018), hypertension (20/80 (25%) vs 33/329 (10.0%), p<0.001), amyloidosis (6/80 (7.5%) vs 5/330 (1.5%), p=0.001), smoking (11.7±13.8 vs 6.5±9.5 packet-year, p<0.001). Baseline disease activity parameters were similar with and without advanced spinal ankylosis [BASDAI 5.7±1.6 vs 5.7±1.7, p>0.05, BASFI 5.2±2.5 vs 4.5±2.5, p>0.05, ESR 35±21 vs 32±23 mm/hour, p>0.05, CRP 3.4±4.6 vs 3.1±3.0 mg/dl, p>0.05]. However, last visit CRP (1.94±3.57 vs 1.08±1.62 mg/dl, p=0.003) and BASFI (3.99±2.51 vs 2.43±2.18, p<0.001) were higher in advanced spinal ankylosis group. Multivariate analysis shown that male sex OR 4.3 (95%CI 1.9-9.8), age OR 1.1 (95%CI 1.07-1.14) and disease duration 1.1 (95%CI 1.05-1.15) were independently associated with advanced spinal ankylosis.
Conclusions In our database, advanced spinal ankylosis is a frequent condition in this group of AS patients treated with TNFi. Male sex and higher disease duration were important risk factors for ankylosis, as expected. Although in those patients, disease activity was supressed after TNFi, impaired functional capacity was still apparent for those advanced spinal ankylosis.
Ann Rheum Dis 2011;70:799–804.
Disclosure of Interest : None declared