Prevalence of Insomnia Symptoms in Patients With Sleep-Disordered...
Objective: To assess the prevalence of insomnia symptoms in patients with objectively diagnosed sleep-disordered breathing (SDB).
Design: Retrospective medical chart review of a representative sample of patients with SDB. Setting: University sleep-disorders clinic and laboratory.
Patients: Two hundred thirty-one patients with SDB were selected from a pool of approximately 2,000 patients with sleep disorders.
Measurements: Data were extracted from intake questionnaires and polysomnographic studies. Results: Of 231 patients with SDB diagnoses, 115 patients reported no insomnia complaints (SDB-only patients) and 116 patients reported clinically meaningful insomnia complaints (SDB-plus patients). Compared to SDB-only patients, SDB-plus patients reported significantly worse mean sleep characteristics consistent with insomnia, including sleep latency (17 min vs 65 min), total sleep time (7.2 h vs 5.6 h), and sleep efficiency (92% vs 75%). SDB-plus patients experienced significantly more psychiatric disorders, cognitive-emotional symptoms, and physical and mental symptoms that disrupted or prevented sleep. SDB-plus patients also reported greater use of sedative and psychotropic medications and had significantly more primary complaints of insomnia, restless legs or leg jerks, and poor sleep quality despite having relatively similar referral rates for sleep apnea or complaints of loud snoring.
Conclusions: Problematic insomnia symptoms were reported by 50% of a representative sample of patients with objectively diagnosed SDB. Research is needed to determine the degree to which insomnia and related symptoms and behaviors interfere with SDB treatment.

Research investigations of insomnia and sleep-disordered breathing (SDB) are becoming more prevalent. Yet, scant research has been conducted on patients with both disorders. Surprisingly, most cited research describing this intuitively frequent combination of the two most common sleep disorders occurred 1 or 2 decades ago and rarely included random samples. Still, the exploratory findings from a few studies point to interesting clinical perspectives about patients with both insomnia and SDB. For example, women with SDB may present with more insomnia features than men, and SDB patients with insomnia appear to suffer from less hypoxia and sleepiness than patients with classic sleep apnea.

The dearth of research in this area may arise from the assumption that SDB patients experience sleep maintenance insomnia or recurrent awakenings without concomitant difficulty returning to sleep. As such, "insomnia" associated with SDB appears to be clinically irrelevant. Current American Academy of Sleep Medicine practice parameters for the diagnosis of SDB in fact depart from an earlier version of the International Classification of Sleep Disorders construct by no longer using the term insomnia in the diagnostic criteria. Most studies or reviews on this topic have attempted primarily to clarify the role of polysomnography in assessing insomnia, and a few of these works have assessed SD

Regardless of how these two common sleep disorders are related, it may prove worthwhile to consider their relationship as a "two-way street," particularly if insomnia symptoms in SDB patients manifest as primary comorbid conditions, requiring treatments distinct from and supplemental to sleep breathing therapies. Speculatively, comorbid insomnia could influence compliance with SDB therapies, such as continuous positive airway pressure (CPAP) or oral airway devices. And, with the growing influence of managed care, a patient with complex sleep disorders (such as comorbid insomnia and SDB) might not receive the level of follow-up required to maximize treatment outcomes. As a preliminary step in learning more about this clinical presentation, the current study focused on the frequency of insomnia complaints in patients with obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS). The study included a representative sample of SDB patients treated at a university sleep-disorders clinic. We hypothesized that a sizeable proportion of patients with objectively diagnosed SDB would report clinically important insomnia symptoms, and that SDB patients who reported comorbid insomnia would report greater symptom distress compared with SDB patients without complications.