DIAGNOSTIC ACCURACY OF LEVEL IV PORTABLE SLEEP TESTS VERSUS POLYSOMNOGRAPHY FOR SLEEP-DISORDERED BREATHING: A SYSTEMATIC REVIEW AND META-ANALYSIS
Obstructive sleep apnea (OSA) affects 3-4% of women and 6-9% of men. In-laboratory overnight Type I polysomnography (PSG) with ≥7 channels is the current ‘gold standard’ for diagnosing OSA. Diagnostic sleep studies can be also conducted at home with Type IV portable monitors (PM) that use fewer channels but offer better comfort and lower costs. We aimed to systematically review the evidence on diagnostic ability of Type IV PMs compared to the PSG in diagnosing patients with suspected OSA.
Participants: patients ≥16 years old with symptoms suggestive of OSA. Intervention: type IV PM applied at home/sleep-lab for diagnosis of OSA. Comparator: in-laboratory PSG. Outcomes: sensitivity, specificity, area under the curve, and level of agreement. Studies: cross-sectional, prospective observational/experimental/quasi-experimental studies. Information sources: MEDLINE and Cochrane library from January 1, 2010 to June 1, 2015. Study selection and data extraction: All stages of the review were conducted independently by two investigators. Information was abstracted on study and participant characteristics, PSG and PMs (name, manufacturer, channels, scoring, etc), and diagnostic performance. The quality of included studies was assessed using the QUADAS tool.
In total, 5,015 abstracts and 103 full text articles were screened to select 22 full text articles for final review. These 22 studies involved a total of 1,565 patients with suspected OSA, and evaluated 10 types of PMs. The quality of studies varied widely. The number of channels of the PMs varied from one to six. Among 22 studies, 17 tested PMs simultaneously with PSG at sleep labs, 4 tested them both at home and at sleep labs, and one tested them at home. All studies used the apnea-hypopnea index (AHI) or respiratory disturbance index (RDI) with different cut-offs to evaluate the diagnostic ability of PMs, and only one study evaluated their performance in combination with clinical diagnosis of OSA. Using an AHI/RDI ≥5 cut-off, the sensitivity of Type IV PMs varied from 67.5 - 100% and specificity from 25% - 100%.
Level IV PMs offer the potential to widen access to treatment for this underdiagnosed condition. Policy recommendations regarding the use in primary and specialty care settings should consider the health and societal implications of false positive and false negative diagnoses, as well as the cost-effectiveness of PM use by setting.