Objective: Depression is the most frequent mood disorder that impairs quality of life and medication adherence in patients with systemic lupus erythematosus (SLE). Although sleep-disordered breathing (SDB) is a contributor to depression in the general population, its prevalence in SLE patients and its impact on depression are not clear. We employed a clinical epidemiologic approach to examine them in a multicenter cohort of SLE patients. Methods: This was a cross-sectional study of 414 Japanese adults with SLE at five university hospitals. The main exposure was high-risk SDB, assessed with the Berlin Questionnaire. The main outcome was moderate to severe depression assessed using the Patient Health Questionnaire-9. Poisson regression models were fitted with a robust error variance to estimate adjusted prevalence ratios (aPRs). Results: The mean age was 47.5 years and the mean body mass index (BMI) was 22.1 kg/m2. The prevalence of high-risk SDB was 15.2% (95% confidence interval [95% CI] 11.9%-19.0%). The prevalence of moderate or severe depression was 19.1% (95% CI 15.4%-23.2%). High-risk SDB was associated with a greater likelihood of moderate to severe depression (aPR 2.62, 95% CI 1.62-4.24). All the 1-, 2-, and 3-positive risk categories for SDB were associated with moderate to severe depression, in a dose-dependent manner. Conclusion: Among patients with SLE, SDB is common, and high-risk SDB is strongly associated with moderate to severe depression. The signs and symptoms of SDB should prompt a simultaneous evaluation for concomitant depression.

NK is a member of the Committee on Clinical Research, Japan College of Rheumatology, and has received grants from the Japan Society for the Promotion of Science, consulting fees from GlaxoSmithKline K.K., and payment for speaking and educational events from Chugai Pharmaceutical Co. Ltd., Sanofi K.K., Mitsubishi Tanabe Pharma Corporation, and the Japan College of Rheumatology. KS has received a research grant from Pfizer Inc. and payment for speaking and educational events from GlaxoSmithKline K.K. Other authors declare no competing interests.

This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant number: JP 19KT0021 and JP 22H03317). The funder had no role in the study design, analyses, interpretation of the data, writing of the manuscript, or the decision to submit it for publication.

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This study complied with the Declaration of Helsinki and the Ethical Guidelines for Medical and Biological Research Involving Human Subjects in Japan. The study protocol was approved by the Institutional Ethical Board of Showa University Hospital (approval number: 22-130-B).

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