The aim of the study is to test the hypothesis that treatment of sleep disordered breathing (SDB) in patients with comorbid chronic obstructive pulmonary disease (COPD) and/or heart failure (HF) with positive airway pressure (PAP) is associated with reduced risk for hospitalizations and death, lower health care utilization, and greater cost-effectiveness.

In this retrospective analysis the health care utilization in patients with COPD and HF will be quantified. Data of patients who additionally underwent a polysomnography or polygraphy between 2012 and 2015 are taken into consideration. The data (risk for hospitalization and death, comorbidities, diagnosis and therapy of SDB, costs of health care utilization) will be collected 12 months before and 12 months after diagnosis of SDB.

The patients' medical records will also be reviewed for compliance to treatment for SDB, and the patients will be classified as treated or untreated. The treated group will be divided into two subgroups: those with "good adherence" to PAP therapy (≥ 4 hours PAP use per night) and those with "poor adherence" to PAP therapy (< 4 hours PAP use per night). Healthcare Utilizations, HF or COPD exacerbations and mortality will be identified by reviewing medical records, National database when available, or self-reported by patient or patient's family through phone interview or questionnaire.

Inclusion Criteria:

• subjects between 21 to 75 years;
• consecutive patients who underwent polysomnography or polygraphy during the period of 01/01/2012 to 31/12/2015.
• diagnosis of COPD and/or HF

Exclusion Criteria:

• age <21 or >75 years

Patient from primary care clinics and sleep medicine centers