Clinical and Polysomnographic Characteristics of Patients with Extreme Obstructive Sleep Apnea, AHI > 100: A Case-Control Study

 Severe obstructive sleep apnea (OSA), defined by apnea-hypopnea index (AHI) as more than 30 events per hour, was previously related to more comorbidity. However, limited studies separated the patients with AHI > 100 from those with a less severe manifestation of the disease.

 The current study aimed at describing the characteristics of this subgroup and comparing them with less severe conditions.

 A retrospective analysis was conducted on 114 patients with OSA. Nocturnal polysomnography was used to diagnose severe OSA. Patients were categorized into two groups: (1) 60 < AHI < 100 (very severe OSA), (2) AHI ≥ 100 (extreme OSA). Demographic, medical history, and polysomnographic variables were evaluated and compared between the two groups.

 Extreme OSA was diagnosed in 19 patients, the mean body mass index (BMI) was significantly higher in this group (39.26 ± 5.93 vs. 35.68 ± 6.45 kg/m2, P = 0.025). They also had lower minimal O2 saturation (65.68 ± 10.16 vs. 74.10 ± 8.74, P = 0.003) and more time with < 90% O2 saturation (T < 90%) (81.78 ± 22.57 vs. 58.87 ± 33.14, P = 0.01). OHS prevalence was significantly higher in the group with extreme OSA (P = 0.04). The most frequent comorbidity was hypertension, with an incidence of 60.5%, for the extreme group, although there was no significant difference between the two groups in terms of clinical associations.

 The current study results suggested that greater BMI and lower minimal O2 saturation, as well as increased T < 90%, were associated with extreme OSA, although no differences were observed in the associated diseases between the compared groups.