Background: Polysomnography (PSG) tests are very complicated and time consuming, despite their clinical benefits in the diagnosis of patients with obstructive sleep apnea hypopnea syndrome (OSAHS). A plasma marker would be desirable to select patients suspected of OSAHS for further PSG studies. We have recently reported that orexin-A concentrations in plasma collected immediately after waking early in the morning were significantly lower in patients with OSAHS than in controls. Objectives: We conducted the present study to assess the clinical usefulness of the measurement of orexin-A concentrations in plasma obtained in the daytime as a diagnostic predictor to screen patients with OSAHS. Methods: Blood samples were collected in the daytime from 19 male patients with suspected sleep-disordered breathing. Plasma orexin-A concentrations were measured by radioimmunoassay before performing PSG. Results: PSG was conducted in all 19 subjects. PSG showed that 14 subjects had OSAHS and 5 subjects did not. Plasma orexin-A concentrations were significantly lower in patients with OSAHS (4.9 ± 0.8 pmol/l, mean ± SE, n = 14) than in control subjects (12.3 ± 1.9 pmol/l, n = 5) (p = 0.0004). Conclusions: These findings suggest that the orexin-A concentration in plasma obtained even in the daytime may be a useful plasma marker for screening OSAHS.
- Obstructive sleep apnea hypopnea syndrome