Diagnostic accuracy of home-based monitoring system in morbidly obese patients with high risk for sleep apnea.

Abstract

No previous studies have validated the use of portable monitoring (PM) for the diagnosis of obstructive sleep apnea (OSA) in morbidly obese individuals. Our aim was to investigate the accuracy of PM for detecting respiratory events in morbidly obese patients that will be undergoing bariatric surgery. This was a prospective study involving patients with body mass index (BMI) ≥35 kg/m(2) who were recruited from the Sleep Clinic of Universidade Federal de São Paulo. Sleep-disordered breathing (SDB) was evaluated during full-night polysomnography (PSG). PM use was randomized and used on two consecutive nights: (1) at home (STDHome) and (2) at the sleep laboratory with PSG (PSG_STDLab). Although 58 participants initially underwent the recordings, 26 (45%) were excluded because of technical problems. The patients' mean age was 42.9 ± 10.9 (SD) years, and 56% were female. The mean BMI was 40.8 ± 5.2 kg/m(2). All patients had high risk for OSA, as defined by the Stop-Bang questionnaire, and the mean apnea-hypopnea index (AHI) was 46.9 ± 30.4/h. The intraclass coefficient of the correlation between AHI_PSG and AHI_STDLab was r = 0.92 (p = 0.0001); the intraclass coefficient for AHI_PSG and AHI_STDHome was r = 0.84 (p = 0.0001). The Kappa index was 0.87 (p > 0.0001) for severe cases. The sensitivity and the positive predictive value increased with the disease severity. A Bland-Altman analysis showed good agreement between the investigated methods. PM is an efficacious method for diagnosing OSA in obese patients who have a high clinical probability of the disease. The method displays good sensitivity and specificity in severe cases; nevertheless, the high rate of data loss must be taken into account.