Natural evolution of sleep apnoea syndrome: a five year longitudinal study

Area of Science:

• Sleep Medicine
• Respiratory Medicine
• Clinical Research

Background:

• Obstructive Sleep Apnoea Syndrome (OSAS) is a common disorder with significant health implications.
• Understanding the natural progression of untreated OSAS is crucial for patient management.
• Previous studies often focus on treated populations, leaving a gap in knowledge regarding natural evolution.

Purpose of the Study:

• To investigate the natural evolution of Obstructive Sleep Apnoea Syndrome (OSAS) in untreated patients.
• To evaluate changes in daytime somnolence, lung function, and nocturnal respiratory disturbances over a minimum of five years.
• To identify factors influencing the progression of OSAS in a non-interventional cohort.

Main Methods:

• Followed 32 patients diagnosed with OSAS who refused treatment.
• Conducted instrumental follow-up including Multiple Sleep Latency Test (MSLT), spirometry, and polysomnography after 5.7 years.
• Compared baseline and follow-up data for Apnoea-Hypopnoea Index (AHI), oxygen saturation (Sao2), Body Mass Index (BMI), and pulmonary function.

Main Results:

• Overall AHI, mean low Sao2, and BMI did not significantly change in the patient group.
• A significant increase in the duration of apneas and hypopneas was observed.
• A subgroup of patients defined as "worsened" showed significant increases in BMI and AHI, and a decrease in mean low Sao2.

Conclusions:

• Untreated OSAS demonstrates a variable natural course, with some patients experiencing significant worsening of respiratory disturbances.
• Increased BMI appears to be a key factor in the progression of OSAS in susceptible individuals.
• Further research is needed to predict individual OSAS trajectories and tailor management strategies.