A two-year prospective study on the frequency and co-occurrence of insomnia and sleep-disordered breathing symptoms in a primary care population

Objective: We aimed to evaluate frequency and co-occurrence of insomnia and sleep-disordered breathing (SDB) symptoms and potential co-morbidity (complex insomnia).

Methods: A prospective self-assessment was conducted for adult patients with no prior sleep issues who presented to community-based primary care clinics for nonsleep-related complaints between November 2009 and June 2012.

Results: A brief sleep health survey (SHS) assessed insomnia and SDB symptoms. Of 801 patients, 660 (82.4%) reported at least one insomnia symptom, and 289 (36.1%) reported an insomnia disorder (Insomnia Severity Index [ISI] >7 and self-reported daytime impairment due to insomnia). At least one SDB symptom was reported by 478 (59.7%) patients, and 177 (22.1%) reported two or more symptoms. Co-occurrence of insomnia and SDB symptoms (minimum of one symptom each of insomnia and SDB) occurred in 50.8% of the sample. Using liberal criteria to assess potential co-morbid disorders (complex insomnia), 187 (23.4%) patients reported an insomnia disorder and at least one SDB symptom. With more stringent criteria, including only those patients with moderate or severe insomnia disorders plus two SDB symptoms, 48 patients (6.0% of the sample or 16.6% of all patients with insomnia disorders) indicated potential complex insomnia.

Conclusions: Co-occurrence of insomnia and SDB symptoms as well as the rate of potential complex insomnia was common among a moderately large sample of primary care patients without prior evaluations or diagnoses of sleep disorders. Clinical and research implications are discussed.