Diagnosis of Obstructive Sleep Apnea Syndrome and Its Outcomes With Home Portable Monitoring* Ana Claudia Tonelli de Oliveira, MD, MSc; Denis Martinez, MD, PhD; Luiz Felipe T. Vasconcelos, MD; Sandro Cadaval Gonc ¸alves, MD, PhD; Maria do Carmo Lenz, MD, PhD; Sandra Costa Fuchs, MD, PhD; Miguel Gus, MD, PhD; Erlon Oliveira de Abreu-Silva, MD; Leila Beltrami Moreira, MD, PhD; and Fla ´vio Danni Fuchs, MD, PhD Background: The use of portable respiratory monitoring (PM) has been proposed for the diagnosis of obstructive sleep apnea syndrome (OSAS), but most studies that validate PM accuracy have not followed the best standards for diagnostic test validation. The objective of the present study was to evaluate the accuracy of PM performed at home to diagnose OSAS and its outcomes after first validating PM in the laboratory setting by comparing it to polysomnography (PSG). Methods: Patients with suspected OSAS were submitted, in random order, to PM at the sleep laboratory concurrently with PSG (lab-PM) or at home-PM. The diagnostic performance was assessed by sensitivity, specificity, positive and negative predictive values, positive likelihood ratio (LR), negative likelihood ratio (LR), intraclass correlation coefficients,  statistic, and Bland-Altman plot. Results: One hundred fifty-seven subjects (73% men, mean age  SD, 45  12 yr) with an apnea-hypopnea index (AHI) of 31 (SD  29) events/h were studied. Excluding inadequate recordings, 149 valid comparisons with lab-PM and 121 with unattended home-PM were obtained. Compared to PSG for detecting AHI > 5, the lab-PM demonstrated sensitivity of 95.3%, specificity of 75%, LR of 3.8, and LR of 0.11; the home-PM exhibited sensitivity of 96%, specificity of 64%, LR of 2.7, and LR of 0.05. Kappa statistics indicated substantial correlation between PSG and PM results. Bland-Altman plot showed smaller dispersion for lab-PM than for home-PM. Pearson product moment correlation coefficients among the three AHIs and clinical outcomes were similar, denoting comparable diagnostic ability. Conclusions: This study used all available comparison methods to demonstrate accuracy of PM in-home recordings similar to that of repeated PSGs. PM increases the possibility of correctly diagnosing and effectively treating OSAS in populations worldwide. (CHEST 2009; 135:330 –336) Key words: diagnosis; home monitor; obstructive sleep apnea syndrome Abbreviations: AHI = apnea-hypopnea index; BMI = body mass index; CI = confidence interval; CPAP = continuous positive airway pressure; ESS = Epworth Sleepiness Scale; LR = likelihood ratio; OSAS = obstructive sleep apnea syndrome; PM = portable respiratory monitoring; PSG = polysomnography; ROC = receiver operating characteristic; SaO 2 = arterial oxygen saturation P ortable respiratory monitoring (PM) is an alter- native to polysomnography (PSG) for diagnosing obstructive sleep apnea syndrome (OSAS), 1–8 relying specifically on cardiopulmonary bioparameters that are recorded in the PSG. 9,10 Type 3 monitors record four or more respiratory signals and have been developed for home use. 11 The diagnosis of OSAS with validated PM has new clinical guidelines issued by the Portable Monitoring Task Force of the Amer- ican Academy of Sleep Medicine. 12 Following the decision tree proposed by the academy, PM can increase the diagnostic capability of the installed sleep laboratories. On the other hand, the guidelines emphasize the deficiency of the current evidence. 12 CHEST Original Research SLEEP MEDICINE 330 Original Research