The prognostic importance of sleep quality in patients with heart failure and sleep apnea: Data from the Norwegian heart failure registry

Background Sleep is one of eight essential factors for cardiac health according to American Heart Association. Sleep apnea (SA) is prevalent in heart failure (HF) patients. No consistent evidence indicated reduced survival associated with comorbid SA, or survival benefit from treatment with positive airway pressure (PAP) in HF patients. Aims To investigate whether self-reported sleep quality associates with excess mortality in HF patients with SA, and if PAP-treatment reduced mortality in treated patients. Methods Data from the Norwegian National HF Registry, including >90% of all patients followed at Norwegian HF outpatient clinics between 2013–2023. Patients completed the Minnesota Living with HF Questionnaire at baseline, which includes a question regarding sleep quality during the last 4 weeks on a scale from 0 (not affected) to 5 (affected severely). Impaired sleep was classified as score 3, 4 and 5. Previous diagnosis of SA, year of onset, and PAP-treatment were recorded by the HF nurse. 6-minute walk test (6MWT), New York Heart Association functional class, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were assessed at baseline. Cox-regression was used to investigate associations with mortality over three years. The model was adjusted for age, sex, body mass index, New York Heart Association functional classification, serum creatinine and comorbidities (stroke, obstructive pulmonary disease, diabetes and cancer). Results Of 24,044 patients with HF, 1,638 (6.8%) patients had SA, of which 1,247 (76.2%) received PAP-treatment for median 4.2 years. Impaired sleep was present in 611 (37%) of patients with SA. Compared to patients without SA, patients with SA and impaired sleep had lower NT-proBNP, higher BMI, shorter 6MWT, worse NYHA-class quality and had increased mortality risk (HR: 1.48, 95% CI 1.20–1.82, p<0.001), whereas those with SA and preserved sleep quality did not (HR: 1.09, 95% CI 0.89–1.32, p=0.37). PAP-treatment was not associated with mortality risk (HR: 1.00, 95% CI 0.78–1.28, p=0.98). Conclusion Reduced sleep quality was associated with reduced functional capacity, worse symptoms and increased long-term mortality risk in the Norwegian HF Registry, while patients with SA and preserved sleep had no excess risk. PAP-treatment was not associated with reduced mortality.Baseline charecteristics