A recent study comparing patient outcomes and physician confidence and decision making for patients with suspected OSA who were managed with limited channel (L3) versus full PSG testing showed that patient outcomes are not inferior when sleep physicians are presented with L3 study data compared with full PSG data.
Since 2008, when home sleep testing was approved by the Centers for Medicare and Medicaid dramatic changes have taken place across the US in both sleep testing and management. Limited channel testing was predominantly driven by changes to reimbursement policies by health insurers (1)
Some physicians remain cautious with regard to whether the L3 devices lead to impaired decision making and inferior patient outcomes and although previous randomized control trials (RCTS)indicated that similar outcomes can be achieved with L3s, these RSTs had significant limitations in that they were conducted in highly selective populations and were not designed as intention to treat (ITT) studies.
The study, carried out in seven centers in Australian and funded by the Australian National Health and Medical Research Council was designed as an IIT, multicenter RCT comparing outcomes and physician decision making.
All patients underwent a full laboratory PSG and were then randomized into one of three groups.
Group 1 received Level 1 which included electroencephalography, electrooculogy, chin and leg electromyography, airflow, thorocoab-dominal bands, snoring sensor, body position, elctro-cardiography (EKG) and oxygen saturation.
Group 2 received Level 3 which included airflow, thorocoabdominal bands, snoring sensor, body position, elctro-cardiography (EKG) and oxygen saturation.
Group 3 received L4 which included oxygen saturation and heart rate.
The data was transferred electronically and manually scored by sleep technicians and reviewed by physicians who were blinded to the PSG data.
Patient outcomes were measured using Functional Outcomes of Sleep Questionaire (FOSQ) to measure primary outcome. This was chosen as previously validated measures of the global impact of excessive sleepiness on functional status (2) and additionally was used in another RCT which evaluated limited channel monitoring (3). Secondary outcome measures were changes in Epworth Sleepiness Scale (ESS) score (4), modified Sleep Apnea Symptoms Questionnaire (SASQ) score (5) and Assessment of Quality of Life (AQol)-8D score at 4 months versus baseline plus satisfaction with physician review.
This is the first multicenter ITT RCT to compare patient outcomes and physician diagnostic confidence in patients tested with PSG, L3 & L4 studies. Patient outcomes in the L3 group were not clinically inferior to outcomes in those managed with full PSG data which supports use of L3 studies in clinical practice.
Those patients managed with L4 were also not inferior to PSG for the primary outcome of change in FOSSQ score. However, symptom improvement (ESS and SASQ scores) seemed worse.
This extensive and comprehensive study supports the use of L3 studies for the diagnosis of sleep apnea but suggests that physicians should be cautious when managing patients with L4 data until further investigations are undertaken to determine secondary outcomes.
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