Pharmacotherapeutic failure in a large cohort of patients with insomnia presenting to a sleep medicine center and laboratory: subjective pretest predictions and objective diagnoses

Abstract

Objective: To measure the frequency of pharmacotherapeutic failure and its association with the diagnosis of sleep-disordered breathing among patients with chronic insomnia disorder.

Patients and methods: In a retrospective review of medical records from January 1, 2005, through December 31, 2012, we identified an inclusive, consecutive series of 1210 patients with insomnia disorder, 899 (74.3%) of whom used sleep aids either occasionally (168 [18.7%]) or regularly (731 [81.3%]). Patients presented to a community-based sleep medicine center in Albuquerque, New Mexico, with typical referral patterns: 743 (61.4%) were referred by primary care physicians, 211 (17.4%) by specialists, 117 (9.7%) by mental health professionals, and 139 (11.5%) by self-referral. Pharmacotherapeutic failure was assessed from subjective insomnia reports and a validated insomnia severity scale. Polysomnography with pressure transducer (an advanced respiratory technology not previously used in a large cohort of patients with insomnia) measured sleep-disordered breathing. Objective data yielded accuracy rates for 3 pretest screening tools used to measure risk for sleep-disordered breathing.

Results: Of the total sample of 1210 patients, all 899 (74.3%) who were taking over-the-counter or prescription sleep aids had pharmacotherapeutic failure. The 710 patients taking prescription drugs (79.0%) reported the most severe insomnia, the fewest sleep-associated breathing symptoms, and the most medical and psychiatric comorbidity. Of the 942 patients objectively tested (77.9%), 860 (91.3%) met standard criteria, on average, for a moderate to severe sleep-associated breathing disorder, yet pretest screening sensitivity for sleep-disordered breathing varied widely from 63.7% to 100%. Positive predictive values were high (about 90%) for all screens, but a tool commonly used in primary care misclassified 301 patients (32.0% false-negative results).

Conclusion: Pharmacotherapeutic failure and sleep-disordered breathing were extremely common among treatment-seeking patients with chronic insomnia disorder. Screening techniques designed from the field of sleep medicine predicted high rates for sleep-disordered breathing, whereas a survey common to primary care yielded many false-negative results. Although the relationship between insomnia and sleep-disordered breathing remains undefined, this research raises salient clinical questions about the management of insomnia in primary care before sleep center encounters.