Predictive values of inflammatory back pain, positive HLA B27 antigen and acute and chronic magnetic resonance changes in early diagnosis of Spondyloarthritis. A study of 133 patients

Abstract

Objectives To analyse the predictive values of inflammatory back pain (IBP), positive HLA B27 antigen, increased C-reactive protein (CRP), Spondyloarthritis (SpA) features, familial history (FH), magnetic resonance sacroiliac joints (MRI-SIJ) imaging and its weight in early SpA diagnosis. Methods 133 patients with back pain, aged <50, duration of the pain <2 years were included. Data such as IBP, HLA B27, increased CRP, SpA features, FH, SIJ´s radiography and MRI were collected for each patient. STIR sequences were classified as strongly positive bone morrow oedema (SPBME ≥2), clearly present and easily recognisable as positive according to the ASAS criterion, weakly positive (WPBME ≥2), suggestive, but not easily recognisable and, clearly negative none of those features. T1-weighted sequences were assessed as positive/negative for erosion, fat metaplasia, backfill and sclerosis, if ≥1, for each lesion was present. MRI images were read by three blinded readers. Results The average age was 38.9 years. 47 (35.3%) patients received SpA diagnosis according to the clinical opinion. IBP was highly specific, 0.81 and sensitive, 0.83. HLA B27 was positive in a half of the SpA patients. SPBME ≥2 provided a great specificity, 0.94 and an acceptable sensitivity, 0.79. Erosion was significantly more frequent in SpA patients (72% vs 7%), specificity 0.93. The addition of erosion ≥1 to the WPBME ≥2 noticeably improved specificity, 0.98, although slightly decreased sensitivity, 0.64. Fat metaplasia and backfill were highly specific, but poorly sensitive. Factors forecasting positive diagnosis were IBP, followed by SpA features and increased CRP. Conclusions At the onset, IBP might be a good marker for selecting patients with suspicion of SpA. The addition of erosion to the ASAS criterion might be helpful for early diagnosis, especially in patients with doubtful STIR imaging where BME is present but it is hard to determinate whether the ASAS “highly suggestive” criterion is met.

The Role of Skeletal Radiology and the Limits of Serologic Assays in Distinguishing among the Causes of Inflammatory Arthritis

“…Clinical diagnosis of RA was based on fulfilment of the 2010 ACR/EULAR criteria for RA [32]. Clinical diagnosis of spondyloarthropathy was based on the current classification criteria for psoriatic arthritis and axial spondyloarthritis [33].…”

Human leucocyte antigen-B27 testing in clinical practice: a global perspective

“…However, in the European White population, HLA-B27 has a high positive likelihood ratio of 9.0 for the diagnosis of axSpA [49]. Therefore, it was incorporated in several referral strategies [50][51][52] because it is easy to prescribe, clear to interpret, and has a moderate one-time cost. Globally, in a target population consisting of patients with chronic low back pain and onset before 45 years of age, when a patient is referred to the rheumatologist based on HLA-B27 positivity and inflammatory back pain, the probability of having an axSpA diagnosis is about 60%.…”

Practical Significance of Biomarkers in Axial Spondyloarthritis: Updates on Diagnosis, Disease Activity, and Prognosis

“…HLA-B27 testing is one of the most widely used genetic tests for any common disease, being demonstrated in up to 90-95% of AS cases compared to the general population, in which HLA-B27 is found in only 8% of cases [ 4 ]. HLA-B27 prevalence varies within different continents and ethnic/racial populations [ 39 , 40 , 119 ]. Some studies have demonstrated that HLA-B27 can predict treatment response and patients with positive HLA-B27 have a better response to TNF inhibitors than negative HLA-B27 patients [ 120 ].…”