Radiographic, non-radiographic axial SpA behave similarly over time
The incidence of peripheral and extra-rheumatic symptoms, as well as disease burden, remain similar over a period of at least 5 years between patients with radiographic and nonradiographic axial spondyloarthritis, according to data published in the Annals of the Rheumatic Diseases.
“The fact that only 5.1% of patients with recent axSpA shifts from [nonradiographic (nr)]-axSpA to [radiographic (r)]-axSpA over 5 years prompts a debate concerning the concept of nr-axSpA: Some people suggest that patients classified as nr-axSpA might actually be suffering from a disease different from r-axSpA, while others suggest that nr-axSpA could be a self-limited form of axSpA with a rapidly favorable course,” Clementina López-Medina, MD, PhD, of Hospital Cochin, in Paris, and colleagues wrote.
“This debate is particularly important in North America, where the Food and Drug Administration expressed several concerns about the incompletely characterization of the natural history of axSpA, which led to the non-approval of several biological disease-modifying antirheumatic drugs (bDMARDs) to treat patients with nr-axSpA,” they added.
To compare clinical manifestations and disease activity among patients with radiographic and nonradiographic axial SpA over a 5-year period, López-Medina and colleagues studied follow-up data from the Devenir des Spondylarthropathies Indifferénciées Récentes (DESIR) cohort. According to the researchers, DESIR is a prospective cohort of 708 adults aged 18 to 50 years with recent-onset axial SpA, recruited consecutively from 25 centers in France. For their study, López-Medina and colleagues included 669 patients with X-ray data available, 185 with radiographic and 484 with nonradiographic axial SpA.
The researchers compared the incidence of first peripheral and extra-rheumatic manifestations between the two groups using incidence rate ratio and Cox regressions adjusted for sex, age and treatment with TNF inhibitors. In addition, they compared mean values of patient-reported outcomes and sick leave during the 5-year follow-up period using mixed models adjusted for sex, age, TNF inhibitors and baseline values.
According to the researchers, patients with radiographic axial SpA demonstrated a significantly higher prevalence of males at baseline. However, after adjusting for age, sex and TNF inhibitors, Cox regressions for peripheral and extra-rheumatic manifestations failed to demonstrate any significant differences between the two groups. Mixed models also revealed similar mean levels in patient-reported outcomes and days of sick leave between both groups through 5 years.
“In this study we observed that both r-axSpA and nr-axSpA seem to behave similarly over time since the incidence of peripheral and extra-rheumatic manifestations are not different after 5 years of follow-up,” López-Medina and colleagues wrote. “Although the nr-axSpA group showed a greater disease burden, these differences disappeared after adjusting for intermediate variables, suggesting the influence of multiple factors on questionnaires scores. These highlighted results confirm the concept of axSpA as a single disease, which implies that both r-axSpA and nr-axSpA patients should be treated with equal priority.” – by Jason Laday
Disclosure: The researchers report no relevant financial disclosures.