Repeated assessment: Is it worth it?
Despite the positive findings described above, residual diagnostic uncertainty remained for 15% of patients, representing an obstacle to initiating an appropriate treatment. Therefore, it is important to understand whether and how the repeated assessment of axSpA features is of value for a definite diagnosis.
This last question was addressed in a second abstract also presented by Dr. Marques that focused on the yield of repeated assessment in CBP patients with suspected axSpA from the SPACE cohort. The main outcome of the study was the clinical diagnosis of definite axSpA at 2 years. Compared with baseline, at the 2-year evaluation 32 patients changed their diagnosis and were classified as definite axSpA: Sixteen were previously described as uncertain axSpA at baseline, 11 as uncertain no axSpA, and 5 as definite no axSpA.
On average, three axSpA features were present at baseline with one or two adjunctive features found throughout the study that led to the final diagnosis of definite axSpA. These adjunctive features were most commonly response to NSAIDs and sacroiliitis on MRI. Dr. Marques and colleagues concluded that the yield of repeated assessment in this setting was modest for a new diagnosis of definite axSpA. “Usefulness of repeating MRI in terms of diagnostic yield is low but can be considered in HLA-B27+ patients, especially if male,” Dr. Marques said, commenting on the analysis of SpA features in patients who changed their diagnosis to definite axSpA at 2 years.
“The early diagnosis of axial spondyloarthritis remains a challenge,” Dr. Sepriano said in commenting on the second SPACE study. “Probably one of the main reasons is the yet suboptimal awareness of the [full spectrum] of the disease in a primary care setting, in which most patients will first show up to get medical care. It is now well-known that patients do not always have changes in pelvic radiographs and that waiting for these to make a diagnosis of [radiographic] axSpA results in further delay and in missing many patients who will never develop these changes.
“Still, recognizing the clinical picture of early axSpA and differentiating it from other more common causes of chronic back pain (e.g., degenerative spinal disease) can sometimes be difficult. Continuous efforts in raising awareness and in education will likely result in further reducing the diagnostic delay gap and, as such, improve the prognosis of this often-debilitating rheumatic inflammatory disease.”
One epidemiologic size does not fit all
According to data from the International Map of Axial Spondyloarthritis (IMAS), axSpA clinical phenotype presentation shows great heterogeneity around the world. Marco Garrido-Cumbrera, PhD, of the University of Seville in Spain, presented the results of an analysis of an IMAS online survey (2017-2022).
The study, supported by Novartis, aimed at exploring differences in axSpA clinical phenotype presentation in a large sample of unselected patients: a total of 5,557 individuals from 27 countries across five regions. The results showed statistically significant differences among countries in almost all the analyzed characteristics, from age at onset of symptoms (the highest in Latin America) to HLA-B27 positivity frequency (lowest in Latin America and highest in Asia).
Differences also emerged in the presence of a positive family history of the disease (most common in Europe) and of physical and mental comorbidities (common in Africa). The authors also reported treatment data showing that most of the patients had used NSAIDs, and almost half of the patients had ever taken biologic disease-modifying antirheumatic drugs. Data also showed a mean delay in diagnosis of 7 years, with the longest values observed in South Africa and the lowest in Asia.