clinical and polysomnographic characteristics of patients with extreme obstructive sleep apnea, ahi >100: a case-control study

Background: severe obstructive sleep apnea (osa), defined by apnea-hypopnea index (ahi) as more than 30 events per hour, was previously related tomorecomorbidity. however, limited studies separated the patients with ahi> 100from those with a less severe manifestation of the disease. objectives: the current study aimed at describing the characteristics of this subgroup and comparing them with less severe conditions. methods: aretrospective analysiswasconductedon114 patients with osa. nocturnalpolysomnographywasused 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. results: extreme osa was diagnosed in 19 patients, the mean body mass index (bmi) was significantly higher in this group (39.26 5.93 vs. 35.686.45 kg/m2, p = 0.025). they also had lower minimal o2 saturation (65.6810.16 vs. 74.108.74, 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. conclusions: 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.