POS1156 FACTORS ASSOCIATED WITH TIME TO DIAGNOSIS OF AXIAL SPONDYLOARTHRITIS IN A UK POPULATION. A CROSS-SECTIONAL OBSERVATIONAL STUDY

Prior, J.A.; Daud, N.; Bajpai, R.; Partlett, C.; Prior, Y.; Stevenson, K.; Battista, S.; Jones, G.T.; Macfarlane, G.J.; Packham, J.

Abstract

Background:
Axial spondyloarthritis (axSpA) diagnosis is frequently delayed, with a median time from symptom onset to diagnosis of 2-5 years. Although many studies report prolonged time in receiving a diagnosis of axSpA, many patient and healthcare factors with the potential to influence the extent of such delay in UK populations, remain poorly understood.

Objectives:
To examine which patient and healthcare factors are associated with the time to diagnosis experienced by people with axSpA in the UK.

Methods:
Secondary analysis of cross-sectional data was conducted on a newly combined dataset containing people with axSpA from three existing UK datasets. Data was included from: a) the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS), a registry containing people with axSpA recruited from 83 secondary care centres in England, Scotland and Wales, b) the Scotland Registry for Ankylosing Spondylitis (SIRAS), a nationwide secondary care disease registry that collected clinical and patient-reported information on those aged 16≥ years with a clinical diagnosis of Ankylosing Spondylitis (AS) in Scotland and c) the Evaluation of ankylosing spondylitis quality of life (EASi-QoL) cross-sectional study, which included people with axSpA/AS randomly selected from existing clinical databases in 10 UK secondary care rheumatology centres. All three datasets were combined to form a single working dataset. Data from factors across the three datasets were combined and compared against our primary outcome of interest, the length of time to receive a diagnosis of axSpA. Descriptive statistics were first reported to characterise the sample. The relationship between individual factors and time to diagnosis was then examined using a two stage Individual Participant Data (IPD) analytical approach. Stage one generated a Rate Ratio (RR) and 95% confidence interval (CI)) for each factor within each separate dataset using negative binomial regression. The two-stage step then combined data from each available dataset for each factor, generating a pooled RR (95%CI). Crude RR were initially reported, followed by values adjusted for age, gender and age at axSpA symptom onset.

Results:
The three combined UK datasets provided a total sample of 5191 people with axSpA, for which we were able to determine a time to diagnosis for 3955 (76.2%). The final combined sample had a mean age of 48.6 years (SD 13.9), 70.5% were male and 62.8% were currently employed. The median time to diagnosis was 4 years (IQR 1-11). Time to diagnosis in this sample was compared against 75 available factors. After adjustment, 54 of the examined factors were not associated with time to axSpA diagnosis, 18 factors were significantly associated with experiencing a longer time to diagnosis, and three with a shorter time to diagnosis. Factors associated with longer time to diagnosis included demographic factors: such as ‘age at axSpA symptom onset', with increasing RR as each age category increased (<20=1.524(1.239, 1.875), <25=1.568(1.201, 2.048), <30=1.668(1.186, 2.345), <35=1.893(1.367, 2.622), <40=2.029(1.347, 3.055) & <45=2.308(1.549, 3.440)), increasing Body Mass Index (BMI) (1.014 (1.006, 1.021) and social deprivation, with the least deprived (1.186 (1.068, 1.317) experiencing more delay than the most deprived. Of the clinical factors: those with an episode of uveitis in the last year (1.100 (1.055, 1.146), low back pain for longer than 3 months (1.753 (1.075, 2.857)) and those with anxiety (1.009 (1.001, 1.017)) or depression (1.014 (1.006, 1.023)) as identified by the Hospital Anxiety and Depression Scores (HADS) all experienced longer time to diagnosis than those without each respective condition. Finally, those reporting increased fatigue (1.011 (1.004, 1.017)) and the most severe categories on the Jenkins Sleep Scale (impacted for 22-31 days) in the domains of ‘night waking' (1.188 (1.033, 1.367)), ‘inability to stay asleep' (1.139 (1.007, 1.288)) and ‘waking tired' (1.163 (1.007, 1.344)) were all associated with increased time to axSpA diagnosis. Having a pervious diagnosis of arthritis (0.870 (0.799, 0.947)), experiencing improved LBP with exercise (0.833 (0.736, 0.942)) and for those with Psoriasis, an increasing proportion of skin affected by this condition (0.863 (0.748, 0.997)) were all associated with reduced time to diagnosis.

Conclusion:
This analysis of the largest combined observational UK dataset demonstrates that many individual factors are not associated with time to diagnosis. This highlights the difficulty, especially in primary care of correctly identifying potential cases for Rheumatology referral. However, several factors did have a significant association. Interestingly, although time to diagnosis was significantly longer in the presence of some clinical factors typically associated with axSpA, (i.e., uveitis, LBP longer than 3 months), increasing area of psoriasis skin involvement was associated with reduced delay. Psoriasis body surface area may present an opportunity to identify people with comorbid axSpA, although this only affects a relatively small proportion of the axSpA community. Some factors (such as BMI, anxiety, depression, fatigue, trouble sleeping) may be influencing clinicians' differential diagnoses, leading them to initially consider conditions other than axSpA, and therefore prolonging the time to diagnosis. Although these results should be considered in the context of cross-sectional analysis and relatively small effect sizes, the examined factors demonstrate the importance of educating clinicians on common comorbid links and that refinement of referral strategies to incorporate the most sensitive factors at population-specific level is needed.

REFERENCES:

NIL.

Acknowledgements:
AbbVie and Pfizer funded SIRAS, AbbVie, Pfizer, and UCB funded BSRBR-AS. The BSRBR-AS is supported by the British Society for Rheumatology and they have received funds for the registry from AbbVie, Pfizer, and UCB. The companies have no input in determining the topics for analysis or the work involved in undertaking it, but they do receive an advance copy of study output on which they may make comments.

Disclosure of Interests:
James A. Prior: None declared, Noor Daud: None declared, Ram Bajpai: None declared, Christopher Partlett: None declared, Yeliz Prior: None declared, Kay Stevenson: None declared, Simone Battista: None declared, Gareth T. Jones Janssen, AbbVie, Pfizer, UCB, Amgen, Menarini, Shionogi. All grants paid to employer, Gary J. Macfarlane: None declared, Jonathan Packham: None declared.
© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.

Citation

Prior, J., Daud, N., Bajpai, R., Partlett, C., Prior, Y., Stevenson, K., Battista, S., Jones, G., Macfarlane, G., & Packham, J. (2025, June). POS1156 FACTORS ASSOCIATED WITH TIME TO DIAGNOSIS OF AXIAL SPONDYLOARTHRITIS IN A UK POPULATION. A CROSS-SECTIONAL OBSERVATIONAL STUDY. Poster presented at EULAR 2025: European Congress of Rheumatology, Barcelona, Spain

• Presentation Conference Type: Poster
• Conference Name: EULAR 2025: European Congress of Rheumatology
• Start Date: Jun 11, 2025
• End Date: Jun 14, 2025
• Acceptance Date: Jun 11, 2025
• Online Publication Date: Jun 18, 2025
• Deposit Date: Jun 30, 2025
• Journal: Annals of the Rheumatic Diseases
• Print ISSN: 0003-4967
• Electronic ISSN: 1468-2060
• Publisher: BMJ Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 84
• Issue: S1
• Pages: 1229
• DOI: https://doi.org/10.1016/j.ard.2025.06.506
• Public URL: https://keele-repository.worktribe.com/output/1283353
• Publisher URL: https://www.sciencedirect.com/science/article/abs/pii/S0003496725025580?via%3Dihub