Prospective Randomized Trial of CPAP for SDB in Patients Who Use Opioids

Patients with chronic pain who use opioids appear to be at increased risk for breathing issues during sleep, termed sleep disordered breathing (SDB). Treatment of SDB often consists of use of a device during sleep that provides continuous positive airway pressure (CPAP) via a mask interface. The goal of this study is to determine whether patients with chronic pain who use opioids and have SDB might benefit from the use of CPAP in terms of sleep quality, pain, quality of life, and other measures. In addition, the study will examine whether these individuals are able to adhere to CPAP, which will be important for future studies. Lastly, we anticipate that CPAP won't work for everyone due to the changes that opioids can cause in breathing patterns. We will examine how often CPAP is ineffective, and whether we can predict which individuals are least likely to resolve their SDB with CPAP.

Patients who use chronic opioids for chronic pain daily for \>3 months will be recruited. Patients with recently diagnosed sleep disordered breathing (SDB; defined as an apnea-hypopnea index \>/=5 events/hr) will be studied, but a screening sleep study can be performed if the participant has not had a sleep study, and they will be included if SDB is found. Persons who are already under treatment for SDB with continuous positive airway pressure (CPAP) will be excluded, along with those with, recreational opioid use, cancer pain, limited life expectancy, prisoners, pregnant women, psychiatric disease, and those unable to provide consent or cooperate with research procedures. Potential subjects will discuss the planned research protocol, risks, benefits, and alternatives with the study staff.

Once the individual has given written informed consent, they will be scheduled for a baseline study visit, which will begin in the early evening. Subjects will undergo a comprehensive history and physical exam, questionnaires examining sleep quality, daytime function, pain, and quality of life. The cold pressor test will be administered, which includes submerging the non-dominant hand in a 4 degree Celsius water bath, and reporting the onset of pain and maximal tolerable submersion time.

After these procedures, the subject will be instrumented for an overnight sleep study, which will include the application of electrodes to the scalp (electroencephalogram), beside the eyes (electro-oculogram), chin and legs (electromyogram). Elastic bands will be applied around the chest and abdomen, a pulse oximeter will be affixed to the finger, and airflow monitors placed just inside the nose and outside the mouth. The subject will then be allowed to sleep until the morning. Upon awakening, they will undergo a computer test of alertness.

The subject will then be randomized to two groups. One group will be randomized to active CPAP treatment, for which they will be fitted with a nasal mask and instructed on the use of a commercial self-titrating CPAP machine. They will wear the device each night for the next 8 weeks. Use of the device will be monitored by the study staff, and the subject will be contacted by telephone on a weekly basis to address any issues. The other group will be randomized to usual care, which does not include CPAP treatment during this 8 week time interval.

After 8 weeks, subjects will return to the laboratory and undergo the same testing as the baseline visit. For the sleep study, those in the CPAP group will wear their CPAP device during the recording, while the other group will be tested without CPAP.

Eligibility Criteria:
Inclusion Criteria:

* Age 18+
* Chronic pain
* Chronic opioid use (daily use for \>3 months duration)
* Apnea-hypopnea index \>/= 5 events/hr (screening sleep study will be performed)

Exclusion Criteria:

* Already using CPAP or non-invasive ventilation on a daily basis
* Use of opioids outside medical supervision (i.e. recreational use)
* Pain due to active cancer
* Prisoners
* Pregnancy
* Psychiatric illness other than treated mood disorders
* Life expectancy \<12 months
* Anticipated inability to sleep in the laboratory setting or to use CPAP
* Unable or unwilling to provide informed consent or comply with research procedures