Subjective Sleep Quality and Prevalence of Sleep Disorders in Patients With Severe Asthma

Rationale

Bronchial asthma is a heterogeneous and highly prevalent disease; moreover, it represents one of the main cost of the Italian National Health Care System. According to international guidelines, asthma is characterized by the presence of symptoms such as wheezing, dyspnoea, chest tightness and / or cough, and limitation of expiratory air flow, that vary over time and of severity.

The main therapy consists of the use of inhaled corticosteroids in order to reduce airway inflammation; however, in conditions characterized by frequent exacerbations, patients take oral corticosteroids (OCS) cyclically or chronically to control their symptoms. Asthma symptoms tend to worsen at night and in the early hours of the morning, and the presence of nocturnal symptoms is an important indicator of therapeutic intervention in order to control the severity of the disease.

Several studies have shown that nocturnal symptoms, such as cough and dyspnoea, are associated with circadian oscillations of airway inflammation and physiological variables, with consequent air flow limitation of and bronchial hyperreactivity. Moreover, it is known that patients receiving OCS are subjected to significant alterations of the hypothalamic-pituitary-adrenergic axis function, therefore the assumption of these drugs could cause a modification of the circadian rhythm.

Since sleep fragmentation that accompanies the worsening of nocturnal asthmatic symptoms is probably caused by the degree of severity of nocturnal bronchoconstriction, it is possible that severe asthmatic patients have greater bronchoconstriction and therefore more disturbed sleep.