Determinants of diagnostic delay in axial spondyloarthritis: an analysis based on linked claims and patient-reported survey data.

OBJECTIVES

The objective of this study was to assess the current diagnostic delay in axial SpA (axSpA) and to analyse factors associated with it.

METHODS

A stratified sample of subjects with a diagnosis of axSpA (International Classification of Diseases, 10th Revision code M45) was drawn from health insurance data in Germany and was questioned on disease-related, lifestyle and socio-economic characteristics. The diagnostic delay was calculated as the time from back pain onset until a diagnosis of axSpA. A multivariable linear regression analysis was performed to explore factors associated with the diagnostic delay.

RESULTS

Among 1677 patients with axSpA included in the analysis, the mean diagnostic delay was 5.7 years (median 2.3). Of those, 407 patients were diagnosed in 1996-2005 and 484 patients in 2006-2015. The mean diagnostic delay was not substantially different in both periods: 6.3 years (median 2.6) and 7.4 (2.7), respectively. Multivariable linear regression revealed that female sex [β = 1.85 (95% CI 1.06, 2.65)], negative HLA-B27 status [β = 3.61 (95% CI 2.07, 5.14)], presence of psoriasis [β = 1.40 (95% CI 0.08, 2.73)] and younger age at symptom onset [β = 1.91 (95% CI 1.53, 2.29)] were factors associated with a longer diagnostic delay.

CONCLUSION

The diagnostic delay in axSpA is still unacceptably long. Patients who are female, young at symptom onset, HLA-B27 negative or have psoriasis have a longer diagnostic delay. Specific referral strategies might be necessary in order to decrease the diagnostic delay in patients presenting with these characteristics.