SIESTA - Home sleep study with BresoDx for obstructive sleep apnea: a randomized controlled trial.

STUDY OBJECTIVES: The objectives of this study were to evaluate (1) the accuracy of the clinical diagnosis of obstructive sleep apnea (OSA) informed by the home sleep study with a Type 4 portable monitor BresoDx® versus Type 1 polysomnography (PSG); and (2) agreement of the apnea-hypopnea index (AHI) compared between BresoDx and PSG. MATERIAL AND METHODS: This was a randomized, parallel, multicentre, single-blind, pragmatic controlled trial enrolling adults referred to three Ontario sleep clinics for suspected OSA. Participants were randomized to BresoDx followed by PSG (one-night apart) or PSG followed by BresoDx sleep testing sequence arms. The primary outcomes included the accuracy of clinical diagnosis and OSA severity measured by AHI between tests. RESULTS: In sum, 233 participants completed both sleep studies and 206 completed physician consultation visits. The agreement between clinical diagnosis informed by PSG versus BresoDx was fair (Cohen's kappa coefficient = 0.28). The sensitivity of BresoDx-informed clinical diagnosis against PSG was between 0.86 and 0.89, and the specificity between 0.38 and 0.44. For AHI cut-off of ≥5 events/hour the sensitivity, specificity and positive and negative predictive values were 0.85, 0.48, 0.81 and 0.54. CONCLUSIONS: Home sleep apnea testing with BresoDx can be used in a referral population with a high pretest probability of OSA similar to other Type IV devices. This study complements the existing body of evidence suggesting that home testing with portable devices plays a valuable role for diagnosing of OSA in a variety of settings. SIESTA TRIAL REGISTRATION: www.clinicaltrials.gov (Identifier: NCT02003729).

Diagnostic accuracy of level IV portable sleep monitors versus polysomnography for obstructive sleep apnea: a systematic review and meta-analysis.

PURPOSE: Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder. In-laboratory, overnight type I polysomnography (PSG) is the current "gold standard" for diagnosing OSA. Home sleep apnea testing (HSAT) using portable monitors (PMs) is an alternative testing method offering better comfort and lower costs. We aimed to systematically review the evidence on diagnostic ability of type IV PMs compared to PSG in diagnosing OSA. METHODS: Participants: patients ≥16 years old with symptoms suggestive of OSA;intervention: type IV PMs (devices with < 2 respiratory channels); comparator: in-laboratory PSG; outcomes: diagnostic accuracy measures;studies: cross-sectional, prospective observational/experimental/quasi-experimental studies; information sources: MEDLINE and Cochrane Library from January 1, 2010 to May 10, 2016. All stages of review were conducted independently by two investigators. RESULTS: We screened 6054 abstracts and 117 full-text articles to select 24 full-text articles for final review. These 24 studies enrolled a total of 2068 patients with suspected OSA and evaluated 10 different PMs with one to six channels. Only seven (29%) studies tested PMs in the home setting. The mean difference (bias) between PSG-measured and PM-measured apnea-hypopnea index (AHI) ranged from - 14.8 to 10.6 events/h. At AHI ≥ 5 events/h, the sensitivity of type IV PMs ranged from 67.5-100% and specificity ranged from 25 to 100%. CONCLUSION: While current evidence is not very strong for the stand-alone use of level IV PMs in clinical practice, they can potentially widen access to diagnosis and treatment of OSA. Policy recommendations regarding HSAT use should also consider the health and broader social implications of false positive and false negative diagnoses.

Effects of backrest design on biomechanics and comfort during seated work.

The purpose of this study was to examine the effects of backrest configuration on seatpan and backrest pressure, spinal posture, and comfort. Thirty volunteers (15 male, 15 female) typed a standardized text passage while seated at a computer workstation in five backrest configurations: chair only, chair with a supplementary backrest, and with each of three lumbar pad thicknesses. Pressure, lumbar and cervical angles were collected during 15-min trials. Subjective data were collected during each trial and at the end of the entire protocol. The addition of a supplementary backrest to a standard chair reduced peak and average pressure on the back by 35% and 20%, respectively (P<0.02). Lumbar lordosis was observed only when lumbar pads were used, being greatest with the large pad. Participants preferred backrest configurations that had lower pressure on the back and less lordotic lumbar posture (backrest only or 3 cm lumbar pad), regardless of anthropometrics. Comfort was rated highest in conditions that would not necessarily be considered biomechanically ideal. Further delineation between specific comfort and objective seating variables is required to effectively reduce and prevent low back pain.