Effect of CPAP on Symptoms of Patients With Fibromyalgia and Obstructive Sleep Apnea

Fibromyalgia (FM) is a chronic pain disorder associated with a wide spectrum of sleep disorders. In fact, insomnia and waking unrefreshed are currently considered part of the criteria for diagnosis. Recent studies show that sleep quality and symptoms of FM are inversely correlated. Obstructive sleep apnea (OSA) is a sleep disorder characterized by repeated episodes of complete or partial blockage of the upper airway. Nonrestorative sleep and fatigue are common symptoms of FM and OSA and may suggest related pathophysiology or co-morbidity that is yet to be diagnosed. This prospective randomized controlled clinical trial will enroll adult FM patients who screen positive for OSA by the STOP-Bang questionnaire. OSA will be confirmed by a laboratory polysomnography (PSG) study. After undergoing further baseline questionnaires and investigations, patients confirmed to have FM with moderate to severe OSA will be randomized to one of two different treatments: 1) Treatment for FM at the Chronic Pain Clinic together with Continuous Positive Airway Pressure (CPAP) devices for their OSA OR 2) Control group receiving treatment for FM at the Chronic Pain Clinic only.

Sleep, pain and breathing have a complex multidimensional relationship. Pain disturbs sleep, poor sleep alters the perception of pain and sleep is a vulnerable state of breathing. The central system sensitization affecting the sensation of widespread pain in FM is due to a decrease in the neurophysiologic inhibition of perception of painful stimuli. This is caused by disturbed sleep. Rheumatic disease pathology can be understood in the light of the interference of cytokines and cellular immune functions with the sleeping/waking brain. Sleep disturbances such as unrefreshing sleep, difficulty falling asleep and frequent night awakenings have been reported by over 90% of FM patients. Sleep disturbances may be related to depression through pain and alteration of physical functioning. Depression and sleep disturbances have been proven to contribute to fatigue in FM patients. Although non-restorative sleep and fatigue are the most commonly reported symptoms by FM patients, the exact cause of these problems is not well understood. A study reported that 50% of the women with obstructive sleep apnea syndrome or upper airway resistance syndrome had chronic pain and more than 11 tender points. One case report has suggested OSA as a possible cause for FM. No studies have been conducted to demonstrate the effect of CPAP treatment on symptoms of FM syndrome in patients with OSA.

Eligibility Criteria:
Inclusion Criteria:

* Possesses cognitive and physical capability necessary to comprehend and complete the study questionnaires, as well as how to use CPAP machines.
* Be proficient in English, reading and comprehension at a Grade 6 level (patient or accompanying person).
* Be accessible for follow-up via interview appointments.
* Be able to provide informed consent.
* Has a Widespread Pain Index (WPI) score of ≥7 and Symptom Severity Score (SSS) of ≥5 OR a WPI 3-6 and SSS ≥9 according to 2010 American College of Rheumatology criteria for Fibromyalgia.
* Constant pain scores over the past 8 weeks.
* Newly diagnosed OSA patients with an AHI ≥15 OR AHI ≥5 on laboratory polysomnography with significant symptoms such as daytime sleepiness (Epworth Sleepiness Scale (ESS\>10), or nocturnal symptoms (frequent nocturnal awakenings).

Exclusion Criteria:

* Conditions potentially interfering with comprehension and delivery of informed consent or unwillingness to provide consent.
* Psychiatric conditions interfering with necessary capability to comprehend and complete study questionnaires.
* Non-English speaking.
* Pregnant and lactating women.
* Uncorrectable coagulopathy interfering with phlebotomy.
* Contraindication to the application of a CPAP interface such as significant facial deformities, or skin lesions.
* History of drug or alcohol dependence or abuse within the last 3 months.
* History of primary pain disorders other than Fibromyalgia such as chronic pain disorder.
* History of primary sleep disorders associated with daytime sleepiness other than OSA, such as narcolepsy.
* Patients who do not meet the 2010 American College of Rheumatology Criteria for Fibromyalgia.
* Patients with previously diagnosed OSA who are already on CPAP before the initiation of the study.
* Patients receiving trigger point injections or intravenous lidocaine for pain treatment.
* Patients requiring an urgent sleep physician referral (within four weeks) due to serious medical conditions or safety critical-occupations according to the 2011 Canadian Thoracic Society (CTS) guidelines update e.g. unstable ischemic heart disease, recent cerebrovascular disease, congestive heart failure, refractory systemic hypertension, obstructive/restrictive lung disease, pulmonary hypertension, hypercapnic respiratory failure or pregnancy.