Abstract

Background: the decision to treat patients (pts) with moderate Obstructive Sleep Apnoea (OSA) is often related to the presence of symptoms or comorbidities. There is no consensus about the treatment of asymptomatic pts (Bixler E.O. et al, Eur Respir J 2016; 47: 23-26).

Aims: to analyze the prevalence of cardiovascular and metabolic comorbidities in moderate OSA pts and any predictive factors.

Methods: we conducted a retrospective study on 192 OSA pts, 172 with moderate OSA (Apnoea–Hypopnea Index, AHI, between 15 and 29) and 20 with mild OSA (AHI between 5 and 14), matched for anthropometric parameters, sex and age. Moderate OSA pts were divided in pts with nocturnal respiratory failure (total sleep time with oxyhemoglobin saturation below 90% = 30%) (group A) and pts without nocturnal respiratory failure (group B). For each group we evaluated hypertension, ischemic heart disease, atrial fibrillation and diabetes prevalence. Variables were compared with Chi-square test. A P < 0,05 was considered statistically significant.

Results: 29 pts (17%) were included in group A while 143 pts (83%) were included in group B. The prevalence of hypertension, ischemic heart disease, atrial fibrillation and diabetes was significantly higher in group A than in group B (respectively P=0.001, P=0.04, P=0.03, P=0.02). We also compared group B to the group of mild OSA and no statistical differences were found.

Conclusions: nocturnal respiratory failure in moderate OSA pts is associated with higher prevalence of cardiovascular and metabolic comorbidities. Moderate OSA pts without nocturnal respiratory failure could be considered as mild OSA pts and treated only in case of symptoms.