SAN DIEGO – As if having insomnia or sleep-disordered breathing isn’t challenging enough, some patients turn out to have “complex insomnia” – a combination of moderate/severe insomnia disorders and specific symptoms of sleep-disordered breathing.
“This overlap of insomnia and obstructive sleep apnea is interesting,” Dr. David N. Neubauer said at the annual U.S. Psychiatric and Mental Health Congress.
Dr. David N. Neubauer
According to a study of 810 primary care outpatients with no sleep disorder history who presented for nonsleep-related complaints, 82% had at least one insomnia symptom, 36% met criteria for insomnia disorder, 60% had at least one symptom of sleep-disordered breathing, 51% had at least one insomnia symptom and one symptom of sleep-disordered breathing, while 11% had potential complex insomnia: a mix of symptoms meeting criteria for moderate/severe insomnia disorder and specific sleep-disordered breathing (Sleep Med. 2013;14[9]:814-23). Several other studies have demonstrated a strong prevalence of insomnia in obstructive sleep apnea (OSA) patients, “which is not that surprising,” said Dr. Neubauer, associate director of the Johns Hopkins Sleep Disorders Center, Baltimore. However, at least three sleep studies conducted in older patients with insomnia found a high prevalence of OSA. The largest study, of 394 postmenopausal women aged 55-70 years, found that 67% had an apnea-hypopnea index (AHI) of greater than 5.*
In a separate trial, veterans in the Los Angeles area who were at least 60 years old and had seen a Veterans Affairs outpatient provider in the past 2 years were recruited for an insomnia behavioral intervention trial (J Clin Sleep Med. 2013; 9[11]:1173-8). To be eligible for the trial, participants must have had a sleep disturbance with daytime consequences for at least 3 months; those with a history of sleep apnea diagnosis or treatment were excluded. Interventions included questionnaires, a phone interview, and in-home testing with the WatchPAT system, a portable device from Itamar Medical that can help diagnose sleep apnea. The mean age of the 435 community-dwelling participants was 72 years, and their mean body mass index was 28 kg/m2. The researchers found that the prevalence of OSA – defined as an AHI threshold of 15 or greater – was 47%.
In another study from Stanford (Calif.) University, researchers set out to evaluate the impact of a cognitive-behavioral intervention in people with insomnia and major depression (J Psychosom Res. 2009;67[2]:135-41). The screening consisted of a phone interview, in-person screening, and an overnight polysomnography test. The mean age of the 51 people who completed the screening was 48 years, and 57% were female. The researchers found that 69% of patients had an AHI of 5 or greater. Of those, 29% had an AHI between 5 and 15, 24% had an AHI between 15 and 25, while 16% had an AHI of greater than 25. “It must have been frustrating for these researchers to get a ‘clean’ insomnia population, because so many ended up having sleep apnea as part of their underlying problem,” Dr. Neubauer said.
Clinicians might think that the worse the OSA, the worse the insomnia, “but that’s not necessarily the case, because a lot of people with severe OSA are just really sleepy, and they’re sleeping through the next day,” Dr. Neubauer said. Patients with a combination of OSA and insomnia symptoms “tend to be some of the people with milder sleep apnea, or those who are under the radar, who wouldn’t even get diagnosed with OSA, but they have that same physiologic process of some inspiratory flow limitation.” This subset of patients might meet criteria for upper airway resistance syndrome, which was first described in 1993 and is characterized by repetitive increases in resistance to airflow, increased respiratory effort, absence of oxygen desaturation, brief sleep state changes or arousals, and daytime somnolence. “In the sleep community, the diagnosis of upper airway resistance syndrome is somewhat debatable, because some people think that if you don’t have absolute apnea events, they don’t count [as a sleep disorder],” Dr. Neubauer said. “But there are a lot of people who feel that these ‘under the radar’ events may still have a significant effect on sleep.” Compared with OSA patients, those with upper airway resistance syndrome tend to be younger, female, and have a lower body mass index (Respiration 2012;83[6]:559-66). In addition, he said, sleep-onset insomnia is common, and the condition is associated with functional somatic syndromes, such as headache, irritable bowel syndrome, gastroesophageal reflux, rhinitis, and orthostatic intolerance.
A recent analysis of 14 second-generation antidepressants based on Food and Drug Administration data and pharmaceutical company records found that the Top 5 most likely to cause insomnia, compared with placebo, are bupropion, desvenlafaxine, sertraline, fluvoxamine, and fluoxetine (J Clin Psychopharmacol. 2015;35[3]:296-303). The Top 5 most likely to cause somnolence, compared with placebo, are fluvoxamine, mirtazapine, reboxetine, paroxetine, and desvenlafaxine.