An initial diagnosis of lumbar disc herniation is associated with a late presentation to rheumatologists and a delay in the diagnosis of ankylosing spondylitis

Among all rheumatic diseases ankylosing spondylitis (AS) remains to be the one with, the longest diagnostic delay mostly due to the slow development of radiographic sacroiliitis. In clinical practice, many patients are diagnosed as having lumbar disk herniation (LDH) prior to the diagnosis of AS. Furthermore a number of studies have reported that MRI may reveal findings of lumbar disc herniation in a significant proportion of subjects with no back pain for the last three months. So, In this study we aimed to assess the diagnostic delay in AS patients with and without an initial diagnosis of LDH and the factors that may be associated with the delay.PATİENTS AND METHODS:393 consecutive AS patients (258 male [65.6%], mean age 39.3 ± 10.8 years) from five rheumatology clinics in different geographical regions were included in this analysis. The diagnosis was based on the modified New York criteria. A face to face interview was performed by using a structured questionnaire addressing all the other possible factors that may have lead to the diagnostic delay, including the initial diagnosis of LDH, history of LDH surgery and the specialty of the first consulted physician. Total diagnostic delay was calculated as the time elapsed from the first visit to the physician for back pain until the diagnosis of AS. Factors associated with the diagnostic delay were evaluated by Spearman's correlation and linear regression methods. Kruskall Wallis and Mann Whitney U tests were used for nonparametric group comparisons.RESULTS:Initial diagnosis was recalled by 392 of the 393 patients and LDH was reported by 33% of them. The average delay in diagnosis was 8.12 ± 8.57 years in all patients with AS. The diagnostic delay in patients with an initial diagnosis of LDH vs those without such diagnosis was 9.1 ± 8.5 and 6.2 ± 7.4 years, respectively (p: 0.002). Twenty six patients (% 6.6) had undergone operation for LDH and the diagnostic delay in those patients was markedly higher than those without surgery (13.3 ± 11.3 vs 7.8 ± 8.2 years, p=0.023). Time to first rheumatology visit was also significantly greater in patients with an initial diagnosis of LDH (9.85 ± 8.39 v.s 7.95 ± 7.94 p:0.016) and in patients with a history of LDH surgery (15.46 ± 10.83 v.s 9.04 ± 8.89 p:0.002) compared with other patients, Patients with a diagnosis of LDH at their first visit was less likely to receive an early diagnosis (<5years) than the patients without such an initial diagnosis (OR:0.59 (95% CI: 0.36-0.95). The great majority of the patients (86%) made their first medical visit to a specialist for back pain. Rheumatologists were seen as the initial physicians by only 4% of the patients whereas, 30% consulted physiatrist, 25% consulted orthopedists and 16% consulted orthopedists at their 1st medical visit due to back pain. The shortest delay in diagnosis was observed when rheumatologists were the first consulted physicians (2.9 ± 5.3 years).The delay period for the physiatrists was shorter (6.3 ± 7.6 years) than the orthopedists (9.6 ± 9.1 years) and neurosurgeons (8.8 ± 6.6 years) .Age at onset of spondyloarthritic symptoms, age at onset of back pain, prior diagnosis of LDH, operation history for LDH, first specialty consulted for back pain and education level were correlated with diagnostic delay, but sex, family history, HLA-B 27 status and acute phase response were not. In regression model age at onset of spondyloarthritic symptoms, age at onset of back pain, prior diagnosis of LDH, operation history for LDH and education level were also found to be significant independent predictors of the diagnostic delay.CONCLUSİON:Our results may be biased because it included only patients followed at rheumatology clinics. However we suggest that prior diagnosis of LDH may lead to late presentation of AS patients to rheumatologists, which may contribute to a delay in diagnosis. A relatively high percentage of patients with LDH surgery is of concern, pointing out the necessity of continuous medical education of the specialists who are likely to see patients with back pain, on the concept of spondyloarthritis.KEY WORDS: ankylosing spondylitis, lumbar disc herniation, diagnostic delay, back pain.