Background To address the growing burden of disease and long waiting lists for sleep services, a simplified two-stage model was developed and validated for identifying obstructive sleep apnoea (OSA) in primary care using a screening questionnaire followed by home sleep monitoring.
Methods 157 patients aged 25–70 years attending their primary care physician for any reason at six primary care clinics in rural and metropolitan regions of South Australia participated. The first 79 patients formed the development group and the next 78 patients the validation group. A screening questionnaire was developed from factors identified from sleep surveys, demographic and anthropometric data to be predictive of moderate to severe OSA. Receiver operating characteristic (ROC) curve analysis was used to validate the two-channel ApneaLink device against full polysomnography. The diagnostic accuracy of the overall two-stage model was then evaluated.
Results Snoring, waist circumference, witnessed apnoeas and age were predictive of OSA and incorporated into a screening questionnaire (ROC area under curve (AUC) 0.84, 95% CI 0.75 to 0.94, p<0.001). ApneaLink oximetry with a 3% dip rate was highly predictive of OSA (AUC 0.96, 95% CI 0.91 to 1.0, p<0.001). The two-stage diagnostic model showed a sensitivity of 0.97 (95% CI 0.81 to 1.00) and specificity of 0.87 (95% CI 0.74 to 0.95) in the development group, and a sensitivity of 0.88 (95% CI 0.60 to 0.98) and specificity of 0.82 (95% CI 0.70 to 0.90) in the validation group.
Conclusion A two-stage model of screening questionnaire followed by home oximetry can accurately identify patients with OSA in primary care and has the potential to expedite care for patients with this common sleep disorder.
- Obstructive sleep apnoea
- primary healthcare
- sleep apnoea
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Funding This study was funded by the National Health and Medical Research Council of Australia (grant 426744) who have had no role in the design, conduct, collection, management, analysis or interpretation of data, nor have they been involved in the preparation, review or approval of the manuscript for publication.
Competing interests RDMcE has been in receipt of two honoraria for speaking engagements from the sleep device company Philips-Respironics in the last 5 years. RDMcE and NAA have received a grant of $5m from Philips-Respironics for a large randomised controlled trial of CPAP therapy for obstructive sleep apnoea with additional equipment donations from Philips-Respironics, ResMed and Compumedics (all sleep device companies) for this project. Equipment donations have also been received by RDMcE, CLC-C and NAA from Philips-Respironics, ResMed and Somnomed for a randomised controlled trial of simplified management of OSA in specialist and primary care settings. The source of direct funding for the latter two grants was the National Health and Medical Research Council of Australia. The remaining authors have no conflicts of interest.
Ethics approval This study was conducted with the approval of the Repatriation General Hospital and Flinders Medical Centre, South Australia.
Provenance and peer review Not commissioned; externally peer reviewed.
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