Back pain due to axial SpA?

Axial spondyloarthritis (axSpA) is one of the most common inflammatory rheumatic diseases affecting the axial skeleton. Back pain and limited mobility in the lumbar spine are among the main symptoms. Primary care plays an important role in reducing the diagnosis latency and providing axSpA patients with adequate treatment in good time. In the OptiRef study, an online-based questionnaire was used as a screening tool and compared with conventional medical referral.

Nowadays, it is possible to visualize inflammatory processes in back pain patients using magnetic resonance imaging (MRI) even before structural or functional limitations are present, explained PD Dr. med. Fabian Proft, Charité Universitätsmedizin Berlin [1]. The first manifestation of axSpA usually affects the 20–40 age group. The etiopathogenesis is largely unexplained, but there are indications of a genetic predisposition. It has been found that axSpA is 10 to 20 times more common in people whose parents or siblings are affected. In the early stages of the disease, long-lasting back pain is a dominant symptom. The disease is already more advanced if structural damage to the sacroiliac joint or the spine can be seen in the X-ray examination; this is referred to as ankylosing spondylitis (AS).

Suspected diagnosis: MRI findings are decisive

If axSpA is adequately treated at an early stage, long-term damage can be counteracted, the speaker explained [1]. However, study data shows that there are still considerable diagnostic latencies in some cases. This can be seen in analyses published by the PROCLAIR project in 2019, which showed that the average diagnosis latency for AS/axSpA (n= 1677) was 5.7 years [2]. Although this is a significant improvement on the situation in the early 2000s, when the time from first manifestation of symptoms to correct diagnosis was around 10 years, there is still room for improvement, Dr. Proft emphasized [1]. The prevalence of axSpA is higher in men than in women and around 95% of all axSpA patients can be shown to have a positive HLA-B27 status in a genetic analysis. However, women and people with negative HLA-B27 status can also be affected by axSpA, which is why only an MRI can provide certainty in the event of clinical suspicion, the speaker explained [1].

Medical referral vs. online-based self-referral

In the OptiRef study, patients with chronic back pain and suspected axSpA were referred to a rheumatology assessment either by primary care physicians or via an online self-referral (OSR) tool [3]. In the physician-based referral, classic criteria for axSpA were collected, including age at the first manifestation of back pain lasting at least three months, inflammation, and the presence of a history of axSpA. three months, inflammatory markers (elevated ESR and CRP values), HLA-B27 status and sacroilitis on imaging (Table 1). The online-based self-assessment was operationalized as follows: flyers with the inscription “You are young and have persistent back pain?” were distributed in the Berlin metro, which contained a QR code that led to a short online questionnaire (Tab. 1). People who showed a high probability of axSpA based on the questionnaire results were invited to a rheumatology consultation at Charité Berlin.

Higher hit rate with medical referral, but…

All patients underwent a structured examination including imaging procedures. A total of 39.2% (n=71) in the physician-based group and 19.4% (n=35) patients in the OSR group were diagnosed with axSpA . Despite the better performance of the physician-based referral strategy, the proportion of axSpA diagnoses among patients referred by OSR was 19.4%, significantly higher than the assumed 5% prevalence among patients with chronic back pain. Dr. Proft commented on the OSR result: “This means that 1 in 5 patients who had not been previously diagnosed were correctly diagnosed using a simple tool of just 15 yes/no questions” [1]. Interestingly, a comparison of the participant characteristics of both groups showed that more females were assigned via the OSR in percentage terms and a lower proportion were aware of a positive HLA-27 status. The study authors suggest using the OSR strategy in addition to a physician-based referral strategy to improve early diagnosis and increase awareness of axSpA.

Congress: EULAR Annual Meeting

Literature:

1. «Early identification of axial Spondyloarthritis – presentation of a physician centered and a patient centered approach», PD Dr. med. Fabian Proft, EULAR Annual Meeting, Vienna, 12–15 june, 2024.
2. Redeker I, et al.: Determinants of diagnostic delay in axial spondyloarthritis: an analysis based on linked claims and patient-reported survey data. Rheumatology (Oxford) 2019; 58(9): 1634–1638.
3. Proft F, et al.: Comparison of an online self-referral tool with a physician-based referral strategy for early recognition of patients with a high probability of axial spa. Semin Arthritis Rheum 2020; 50(5): 1015–1021.

HAUSARZT PRAXIS 2024; 19(8): 54–55 (published on 23.8.24, ahead of print)