Impact of Positive Airway Pressure Therapy on Clinical Outcomes in Older Veterans With Chronic Obstructive Pulmonary Disease and Comorbid Obstructive Sleep Apnea (Overlap Syndrome)

Obstructive sleep apnea (OSA) and Chronic Obstructive Pulmonary Disease (COPD) are highly prevalent chronic respiratory diseases in the Veteran population. OSA co-occurring with COPD, known as Overlap Syndrome (OVS), is a complex chronic medical condition associated with grave consequences. OVS is highly prevalent in Veterans. Veterans with OVS may be at increased risk for cognitive deficits, poor sleep quality as well as a reduced quality of life (QoL). The overall objective is to study the effects of positive airway pressure therapy on clinical outcomes in patients with OVS.

There are no studies regarding the impact of PAP therapy on sleep disturbance, cognitive function and quality of life in patients with OVS. The investigators' rationale is that in patients with moderate-severe OVS, PAP therapy will effectively alleviate sleepiness, sleep disturbances and cognitive deficits, and, thereby, improve QoL. 'PAP' includes either continuous positive airway pressure (CPAP) or noninvasive positive airway pressure ventilation (NIPPV).

Objectives:

Specifically, the investigators will study the effectiveness of PAP therapy vs. conservative care in reducing daytime sleepiness and in improving sleep quality and QoL in older Veterans with OVS.

The investigators will also explore whether CPAP is non-inferior to noninvasive positive airway pressure ventilation (NIPPV) in reducing daytime sleepiness, sleep disturbances and neurocognitive dysfunction, and in improving QoL in older Veterans with OVS.

Eligibility Criteria:
Inclusion Criteria:

* OSA with moderate-to-severe disease, AHI 20 per hour by in-lab polysomnography with concomitant moderate-severe COPD based on pulmonary function tests (PFTS) and with past significant history (\>10 pack-years) of smoking
* Male or female gender
* Age greater than or equal to 60 years
* Stable treatment regimen for COPD

Exclusion Criteria:

* Current or prior treatment with PAP or oral appliance
* Central sleep apnea defined as central apnea index \>5 per hour and comprising 50% of AHI
* Known primary neuromuscular diseases
* Disorders that may impact cognitive function including:

  * neurodegenerative disorders
  * traumatic brain injury
* untreated PTSD and/or history of learning disability
* Medicines that may cause or alter sleepiness: sedative hypnotics, or stimulants as these may alter the results
* Patient is actively suicidal due to depression, unstable mental health condition
* Epworth sleepiness score \>16 (severe sleepiness) or a near-miss or prior automobile accident due to sleepiness within the past 12 months
* Narcolepsy is the primary sleep disorder, with requirement of stimulant medications
* Employed as a commercial driver or operating heavy machinery
* On long-term oxygen therapy prior to start of study, more than 12 hr/day
* Patients is unable to use either a nasal or face mask (e.g., facial trauma, claustrophobia)
* Consumption of \>3 alcoholic beverages per day or current use of some illicit drugs, as these may contribute to cognitive deficits
* Patients who cannot give informed consent
* Patients receiving hospice care
* Pregnant women due to unknown risks