Progression of snoring and obstructive sleep apnoea: the role of increasing weight and time

The aim of the present study was to examine the natural evolution of primary snoring and obstructive sleep apnoea (OSA) in adult male patients. Retrospective analysis was performed on 160 untreated patients with primary snoring and mild, moderate and severe OSA who had two polysomnographic recordings. The mean time between recordings (TBR) was 5.1+/-3 yrs. The mean apnoea/hypopnoea index (AHI), body mass index (BMI), and lowest arterial oxygen saturation level during rapid eye movement (REM) and non-REM sleep showed a significant worsening effect. The change in AHI differed among the groups showing a similar significant increase in AHI for primary snoring, mild and moderate OSA and an insignificant decrease for severe OSA patients. Stepwise linear regression showed that only DeltaBMI and time were significant predictors for AHI change. A model for the mean AHI change showed that DeltaAHI = (4.33xDeltaBMI) + (0.66xTBR). After adjusting for confounders, multiple regression analysis indicated that age and high BMI, but not AHI, were significant risk factors for developing hypertension and/or cardiovascular disease. Patients with primary snoring and mild and moderate obstructive sleep apnoea had a similar increase in the apnoea/hypopnoea index over time, which depended mainly on weight gain and, to a lesser extent, on time.