Coexisting UARS and OSA

To study respiratory arousals with and without obstructive sleep apnoea (OSA) in the same patient.

Cross-sectional study, tertiary hospital based.

One year (2007 to 2008).

The study included 100 patients with suspected SDB who underwent split night sleep study. We came up with diagnosis in 97 cases. With calculation of arousal index with & without apnoea/hypopnoea, we were able to divide patients into OSA, combined (OSA+UARS) & Upper Airway Resistance Syndrome (UARS) groups. The outcome of study was as follows - 74 cases of OSA, 12 cases of combined(OSA+UARS), 5 cases of UARS, 3 cases of PLM, 3 cases of OSA+PLM and 3 normal studies. OSA was found to be most common SDB among men (83.1%) in age group 40–70 yrs with sedentary lifestyle and it is strongly associated with weight & BMI. UARS patients were non-obese with active lifestyle and had low threshold for arousals with prolonged nocturnal awakenings and SpO2 ≥ 91% throughout study period.

UARS is not a distinct syndrome. It is merely a part of the disease spectrum of OSAHS. There exists a group that has characteristics of both OSA & UARS. The spectrum of disease is Primary snorers (PS) à UARS à combined (OSA+UARS) à OSA à OSAHS. UARS patients were mostly non-obese with active life style as compared to OSA patients. Also they displayed poor sleep efficiency with more prolonged awakenings compared to OSA patients.