Identifying trajectories of radiographic spinal disease in ankylosing spondylitis: a 15-year follow-up study of the PSOAS cohort.

OBJECTIVES: Little is known with certainty about the natural history of spinal disease progression in ankylosing spondylitis (AS). Our objective was to discover if there were distinct patterns of change in vertebral involvement over time and to study associated clinical factors. METHODS: Data were analysed from the Prospective Study of Outcomes in Ankylosing Spondylitis (PSOAS) observational cohort. All patients met modified New York Criteria for AS and had ≥2 sets of radiographs scored by modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) by two independent readers between 2002 and 2017. Group-based trajectory modelling (GBTM) was used to classify patients into distinct groups of longitudinal mSASSS considering sociodemographic and clinical covariables. The optimal trajectory model and number of trajectories was selected using Nagin's Bayesian information criterion (BIC). RESULTS: A total of 561 patients with 1618 radiographs were analysed. The optimum number of trajectory groups identified was four (BIC -4062). These groups were subsequently categorized as: non-progressors (204 patients), late-progressors (147 patients), early-progressors (107 patients) and rapid-progressors (103 patients). Baseline predictors associated with higher spinal disease burden groups included: baseline mSASSS, male gender, longer disease duration, elevated CRP and smoking history. In addition, time-varying anti-TNF use per year was associated with decreased mSASSS progression only in the rapid-progressor group. CONCLUSIONS: GBTM identified four distinct patterns of spinal disease progression in the PSOAS cohort. Male gender, longer disease duration, elevated CRP and smoking were associated with higher spinal disease groups. Independent confirmation in other AS cohorts is needed to confirm these radiographic patterns.

The changing profile of ankylosing spondylitis in the biologic era.

OBJECTIVE: To compare disease characteristics, comorbidities, and medication utilization of 1141 patients with ankylosing spondylitis (AS) with short (< 20 years) and long (≥ 20 years) disease duration enrolled in the Prospective Study of Outcomes in AS (PSOAS) study over three different periods of time and followed longitudinally. METHODS: Study visits were carried out every 6 months examining disease activity (Bath AS Disease Activity Index (BASDAI), C-reactive protein, erythrocyte sedimentation rate), functional impairment, depression, and medication utilization as well as radiographic severity. Groups were compared with regression models using generalized estimating equation, linear, and Poisson regressions after adjusting for sites and for patients withdrawing from the study at less than 2 years follow-up. RESULTS: Overall, AS patients with long disease duration were more likely to be married, white, receiving disability, and to be with higher functional impairment and radiographic severity, more uveitis, diabetes, hypertension, cardiovascular disease, and osteoporosis, and with less nonsteroidal anti-inflammatory drug (NSAID) and more opioid use than those with short disease duration. Current smoking decreased between 2002 and 2019 regardless of disease duration. Lower baseline NSAID and methotrexate/sulfasalazine use and higher TNF inhibitor usage were seen only in those with shorter disease duration, though NSAID use and functional impairment decreased over time in both groups. Disease activity, depression scores, and NSAID use decreased and anti-TNF use increased in those followed > 8 years. CONCLUSIONS: Patients with AS enrolling in this multicenter longitudinal cohort have different disease profiles and medication utilization over time, perhaps reflecting innovations in treatment and increasing disease awareness. Key Points • The use of NSAIDs, nonbiologic DMARDs, and prednisone has decreased over the past 16 years in patients with AS. • The use of anti-TNF agents has dramatically increased. • In treated patients, disease activity, depression scores, and functional impairment have decreased over time.

Longitudinal associations between depressive symptoms and clinical factors in ankylosing spondylitis patients: analysis from an observational cohort.

OBJECTIVES: Although cross-sectional studies have shown that ankylosing spondylitis-specific factors correlate with depressive symptom severity, the association of these factors over time is unresolved. We examined the demographic and clinical factors associated with longitudinal depressive symptom severity in AS patients. METHODS: We analyzed sociodemographic, clinical, behavioral and medication data from 991 patients from the Prospective Study of Outcomes in Ankylosing spondylitis cohort, and measured depression severity with the Center for Epidemiological Studies Depression (CES-D) Scale administered at approximately 6-month visit intervals. Multivariable longitudinal negative binomial regression models were conducted using generalized estimating equation modeling to assess the demographic, clinical, and medication-related factors associated with depression severity by CES-D scores over time. RESULTS: The median baseline CES-D score (possible range 0-60) was 10.0 (interquartile range = 5, 17). In longitudinal multivariable analyses, higher CES-D scores were associated with longitudinal smoking, greater functional impairment, greater disease activity, self-reported depression, and poor global health scores. Marital status (e.g., being married) was associated with lower CES-D. Adjusted mean CES-D scores in our model decreased over time, with a significant interaction between time and gender observed. CONCLUSION: This study identified longitudinal clinical factors such as greater disease activity, greater functional impairment, and poor global health to be associated with longitudinal depression severity. These factors are potentially modifiable and may help manage depressive symptoms in AS.