Upper airway resistance syndrome: A long-term outcome study

Abstract

This prospective study aimed to assess symptomatic evolution of patients diagnosed with Upper Airway Resistance Syndrome (UARS) four and half years after the initial UARS diagnosis.

For this purpose, 138 UARS patients were contacted by mail between 43 and 69 months after the initial evaluation; 105 responded to the letter and 94 patients accepted to undergo new clinical and polysomnographic evaluations. Initial and follow-up polysomnographic recordings were scored using the same criteria.

Results

Of the 94 patients who completed the follow-up examination, none of them were using nasal CPAP. It was related to refusal by insurance providers to provide equipment based on initial apnea–hypopnea index (AHI) in 90/94 subjects. Percentage of patients with sleep related-complaints significantly increased over the four and half year period: daytime fatigue, insomnia and depressive mood increased by 12 to 20 times. Reports of sleep maintenance sleep onset insomnia and depressive mood was significantly increased. Hypnotic, antidepressant and stimulant prescription increased from initial to follow-up visit (from 11.7% to 61.7%; from 3.2% to 25.5% and from 0% to 9.6%, respectively) with antidepressant given as much for sleep disturbance as mood disorder. The polysomnography results at follow-up showed that 5 subjects had AHI compatible with Obstructive Sleep Apnea Syndrome (OSAS) but overall, respiratory disturbance index had no significant change. Total sleep time was significantly reduced compared to initial visit.

Conclusions

Many UARS patients remained untreated following initial evaluation. Worsening of symptoms of insomnia, fatigue and depressive mood were seen with absence of treatment of UARS.

Introduction

Upper Airway Resistance Syndrome (UARS) (Guilleminault et al., 1993, Guilleminault et al., 2000) is associated with abnormal respiratory effort, nasal airflow limitation, absence of obstructive sleep apnea, minimal pulse oxygen fluctuation with oxygen saturation (SaO₂) equal or greater than 92%, and frequent nocturnal arousals or reflex brainstem activation (Morruzi, 1963). Patients with UARS frequently complain of daytime tiredness and fatigue. It has been emphasized that these patients present more as patients with functional somatic syndromes than those presenting with Obstructive Sleep Apnea Syndrome (OSAS) (Gold et al., 2003, Guilleminault et al., 2001a, Guilleminault et al., 2001b, Guilleminault et al., 2001c). There have been questions about the usefulness of identifying this syndrome independently from the OSAS, and questions on its long-term evolution (Douglas, 2000). The treatment of UARS is not well clarified: nasal continuous positive airway pressure (nCPAP) was used in the initial report (Guilleminault et al., 1993) to demonstrate response to short term upper airway widening during sleep, but long term prescription has had variable success (Guilleminault et al., 2002). Finally not only the incidence of the syndrome is unknown but also is its natural history. To improve our knowledge on several of these points, we designed a prospective study on a retrospective cohort. We questioned the outcome of the diagnostic evaluation and the treatment recommendation performed on subjects labeled UARS patients at least 4 years prior the start of the prospective study. We questioned if their illness had progressed, if their symptoms had changed and if the prescribed treatment (nCPAP) had been helpful. Due to health insurance policies and contractual agreements with health policy payers, regulations of the medical center, and views of the medical center by the surrounding local medical community, our sleep disorders clinic functioned for many years as referral clinic performing diagnosis and treatment recommendations, with a one time patient contact, and no further interaction if not initiated by the referring primary care physician. Due to these specific conditions we built-up our prospective protocol.