Increased incidence of heart failure in patients with severe obstructive sleep apnoea: a long-term prospective cohort study

Abstract

Background : Obstructive sleep apnoea (OSA) is highly prevalent among patients with heart failure. Accumulating research data suggest that this association is bidirectional. Less is known regarding the long-term impact of OSA and continuous positive airway pressure (CPAP) treatment on incident heart failure. Purpose : We addressed the association of severe OSA with development of heart failure, and consequently addressed the impact of efficient CPAP treatment in a sleep clinic cohort. Methods : The “Sleep Apnea Patients in Skaraborg (SAPIS)” project was a single center (two sites), open-label, prospective cohort study, conducted in Sweden between 2005 and 2018. All consecutive adults admitted to the Skaraborg Hospital between 2005 and 2011 were registered in a local database, and the follow-up ended in May 2018. Anthropomorphic and clinical characteristics as well as results of the diagnostic cardiorespiratory recordings were documented. Treatment of OSA was based on the clinical routines. OSA was defined as an apnoea-hypopnoea index (AHI) of at least 5 events/hr, and severe OSA consisted of patients with an AHI ≥30 events/hr. Median follow-up for the entire cohort was 8.8 years (interquartile range 7.5–10.1 years). Data regarding incident heart failure were obtained from the medical records and the Swedish Hospital Discharge Register. CPAP use (downloaded reports from the devices) of at least 4 hrs/night was defined as efficient treatment. Results : Among 4239 patients with diagnostic sleep recordings, 3185 were free of a known cardiac disease at baseline. Severe OSA was observed among 953 (29.9%). Severe OSA significantly predicted incident heart failure (hazard ratio [HR] 2.42; 95% confidence interval [CI] 1.44–4.06) compared to adults with AHI <30 events/hr, adjusted for age, gender, obesity, hypertension and diabetes mellitus. The adjusted HR for severe OSA was 2.82 (95% CI 1.33–5.99) among inefficiently treated/untreated patients whereas the risk was lower but still meaningful among the individuals who were adherent to CPAP (HR 2.25; 95% CI 0.99–5.15)