OSA occurs in non-obese patients,but they may exhibit different characteristics than obese patients with OSA. To elucidate this point,we investigated several physiological and clinical parameters among non-obese and obese OSA patients.
Of 254 patients referred to sleep clinic,we identified 102 patients with OSA(Apnea Hypopnea Index≥5). We classified OSA patients with Body Mass Index(BMI)<30 as non-obese and those with a BMI≥30 as obese. We conducted a retrospective evaluation that included demographic,physiological and clinical data and compared the non obese and obese groups. For statistical comparisons, continuous variables were analyzed by student’s t-test and categorical variables by chi-square. Fisher’s exact test was used for analysis when a variable contained less than 5 observations.
Of 102 patients with OSA,17(16.7%)were non-obese and 85(83.3%)were obese. The groups of non-obese and obese OSA patients differed significantly in four parameters. Mean AHI was 13.5 in the non-obese group and 27.6 in the obese group(P= 0.03). Non-obese patients were older(average age 57.1 years compared to 48.3 years among obese patients)(t-test,p= 0.01);used more sedatives(usage of one or more sedatives by 52.9% in non-obese group compared to 24.7% in the obese group)(Chi-square,p= 0.02);and,exhibited less upper airway narrowing(23.5% of the non-obese group compared to 55.1% in the obese group)(Chi-square,p= 0.02). Only one non-obese patient(5.9%) was younger than 50,compared to 48 patients(56%)in the obese group(Chi-square,p<0.0001). There were no significant differences between non-obese and obese OSA patients in gender,family history of OSA,facial malformations,adenoid or tonsillar enlargement,smoking,co-morbid conditions and use of narcotics.
In our study,about 1 in 5 patients with OSA was non-obese,suggesting OSA is not limited to obese persons. Non-obese persons differed from obese persons in several important characteristics. We report for the first time that excess use of sedatives occurred in non-obese OSA patients compared to obese patients.
OSA is milder in non-obese patients and is unlikely in non-obese patients who are less than 50 years old.
Ammar Ghanem, None.