Background: Sleep disorders are more prevalent in patients with ankylosing spondylitis (AS) compared to the general population. Sleep disturbance in AS, in addition to pain and fatigue, can lead to impaired physical function and reduced quality of life.

Objectives: The primary objective was to determine the prevalence of sleep disturbance in patients with AS in a real-world Australian cohort using the Insomnia Severity Index (ISI) and Multivariate Apnoea Prediction Index (MAPI). ISI score of ≥ 15 is considered clinical insomnia. MAPI values below 0.05 are suggestive of clinical apnoea.

Methods: Routinely collected, de-identified clinical data were sourced from the OPAL dataset. Patients aged between 18 and 95 years with a diagnosis of AS and who had completed at least one ISI or MAPI questionnaire between Jan-2019 and Sept-2020 were included. ISI and MAPI questionnaires were emailed to patients using OPAL’s electronic patient reported outcome (ePRO) delivery method or completed in the clinic using a smart device and returned to the patient’s file using a QR code. Disease activity was assessed using BASDAI collected at the same time as the sleep questionnaires. Age, sex and duration of symptoms were used to propensity match patients in the Il-17ai and TNFi group in a 1:2 ratio.

Results: 495 of the 5,323 patients identified with AS completed a questionnaire and were included in the analysis (n=395 TNFi, n=48 Il-17ai (secukinumab), n=52 other therapies). 142 were included in the propensity score matched population (n = 94 TNFi, and n = 48 Il-17ai). In the overall population the mean (SD) age was 48.3 (13.6), 55.4% were males, the mean (SD) BMI was 30.1 (19.6) at the index date and 4.8% reported depression. 51.7% had an optimal disease control (BASDAI <4). The mean (SD) ISI score was 8.6 (6.2). 48.1% reported no clinical significant insomnia, 32.7% reported subthreshold insomnia, 16% reported clinical insomnia (moderate severity) and 3.2% reported clinical insomnia (severe). The mean (SD) MAPI score was 0.4 (0.3). 292 patients (59.0%) had low risk of clinical apnoea, 134 patients (27.1%) had high risk of clinical apnoea and 69 patients 13.9% had not completed the MAPI questionnaire. In the propensity scored matched population, the TNFi and Il-17ai groups had mean (SD) ISI scores of 9.1 (6.6) and 8.9 (5.9) at index, respectively (p = 0.83) and mean (SD) MAPI scores of 0.3 (0.2) and 0.4 (0.3) at index, respectively (p=0.046), however a higher percentage of overweight and obese patients were identified in the Il-17ai treatment group. Ordered logistic regression analysis of the relationship between demographics and ISI in the matched population found that patients with BASDAI ≥4 were seven times more likely to experience greater sleep disturbance (OR 7.29, 95%CI 2.37 to 22.46, p=0.001) than those with BASDAI <4.

Conclusion: In this real-world AS cohort, poor disease control was associated with sleep disturbance, despite bDMARD therapy. Little difference was observed between TNFi and Il-17ai treatment. Screening for sleep disturbance and fatigue in routine clinical care may provide a more holistic view of the burden of this disease.

Acknowledgements: The authors acknowledge the members of OPAL Rheumatology Ltd and their patients for providing clinical data for this study, and Software4Specialists Pty Ltd for providing the Audit4 platform. We acknowledge WriteSource Medical Pty Ltd for providing statistical services. Funding for this study was provided by Novartis.

Disclosure of Interests: Kathleen Tymms: None declared, Belinda Butcher: None declared, Tracey Sletten: None declared, Tegan Smith: None declared, Catherine OSullivan: None declared, Geoff Littlejohn Consultant of: AbbVie, Bristol Myers Squibb, Eli Lilly, Gilead, Novartis, Pfizer, Janssen, Sandoz, Sanofi and Seqirus., Ricky Sadler Employee of: Current employee of Novartis, Rebecca Tronnberg Employee of: Current employee of Novartis, Hedley Griffiths Consultant of: AbbVie, Gilead, Novartis and Lilly.