Gender Differences in the Clinical and Polysomnographic Characteristics Among Australian Aboriginal Patients with Obstructive Sleep Apnea

Sumit Mehra,1,2 Ram H Ghimire,1 Joy J Mingi,3,4 Monica Hatch,1 Himanshu Garg,1 Robert Adams,5 Subash S Heraganahally1,3 1Department of Respiratory and Sleep Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia; 2Department of Respiratory and Sleep Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia; 3Darwin Respiratory and Sleep Health, Darwin Private Hospital, Darwin, Northern Territory, Australia; 4Department of Public Health, Charles Darwin University, Darwin, Northern Territory, Australia; 5Adelaide Institute for Sleep Health, a Flinders Centre for Research Excellence, Bedford Park, South Australia, AustraliaCorrespondence: Subash S Heraganahally Email hssubhashcmc@hotmail.comBackground: In this study, we assessed the clinical and polysomnographic (PSG) characteristics according to gender among Australian Aboriginal men and woman diagnosed to have obstructive sleep apnea (OSA).Methods: In this retrospective study, all adult Aboriginal patients over 18 years of age diagnosed to have OSA with an apnea hypopnea index (AHI) > 5/hour over a 5 year period were included.Results: Of the 337 patients (168 females and 169 males), who underwent a diagnostic PSG, 297 (88%) were diagnosed to have OSA (AHI) > 5/hour), 154/297 males (52%) and 143/297 females (48%). Amongst male and female patients with OSA, 63% and 37% were in the severe spectrum (AHI> 30/hour). The male cohort had higher stage N1 NREM sleep (P< 0.001), reduced N3 NREM sleep (P< 0.001), higher AHI severity (P< 0.001), higher NREM AHI (P< 0.001), and high arousal index (P< 0.005). REM sleep-related AHI was higher among female patients with all severity of OSA, along with severe oxygen desaturation during REM sleep. Among patients with severe OSA, the female cohort were younger (age 46 years vs 49 years, P=0.030) and had higher BMI with all severity of OSA, while males had larger neck circumference compared to females. Hypertension increased the odds of severe OSA versus the combined odds of mild and moderate OSA for both genders.Conclusion: This study highlights some important differences in the way sleep apnea manifests in Australian Aboriginal males and females and further studies are warranted to explore avenues to look for a physiological basis for these observations and targeted interventions.Keywords: aboriginal, ethnic, female, gender, male, obstructive sleep apnea