Author: Ching Li Chai-Coetzer
Chai-Coetzer, Ching Li, 2012 Simplified Pathways for the Diagnosis and Management of Obstructive Sleep Apnea in Primary Care, Flinders University, School of Medicine
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Obstructive sleep apnea (OSA) is highly prevalent in the Australian community and throughout the world. With growing evidence linking OSA to adverse health consequences and development of effective therapies such as continuous positive airway pressure (CPAP), there has been a steady rise in the demand for laboratory-based sleep testing and specialist consultation. Alternative, cost-effective models of care for OSA are needed to increase patient access to sleep services. Primary care would be an ideal setting for development of a simplified strategy for OSA diagnosis and management. In the first study (Chapter 2), we developed and validated a two-step diagnostic model for moderate-to-severe OSA consisting of a screening questionnaire and overnight home oximetry. Patients aged 25 to 70 years who were seeing their general practitioner (GP) for any reason at one of 6 primary care clinics completed an Epworth Sleepiness Scale (ESS) and Berlin Questionnaire. They underwent simultaneous recording with a two-channel ApneaLink monitor and full polysomnography (PSG) to identify variables predictive of OSA and to validate the portable monitoring device. Snoring, waist circumference, apneas and age were most predictive of OSA and incorporated into a screening questionnaire (receiver operating characteristic area under curve (ROC AUC) = 0.84 [95%CI: 0.75-0.94], p<0.001). ApneaLink oximetry with a ≥3% dip rate was highly predictive of OSA (ROC AUC=0.96 [0.91-1.0], p<0.001). The two-stage diagnostic model had a sensitivity of 0.97 [0.81-1.00] and specificity of 0.87 [0.74-0.95] in the development group, and sensitivity of 0.88 [0.60-0.98] and specificity of 0.82 [0.70-0.90] in the validation group. Thus, the two-step model was shown to be accurate in identifying patients with OSA in primary care. The development and evaluation of a six-hour education program for GPs which was accredited by the Royal Australasian College of General Practitioners is described in Chapter 3. GPs completed an attitudes and knowledge questionnaire before and 2 weeks after attendance at the program, and then again after 17 to 30 months. Two weeks post-education, there were significant improvements in the level of confidence in managing OSA and CPA therapy, and an improvement in knowledge test scores. Improvements in attitudes and knowledge from baseline were sustained on long term testing. Chapter 4 details the results of a prospective, randomised controlled study conducted to evaluate the clinical efficacy and cost-effectiveness of a simplified model of care for OSA in general practice. Patients with OSA were identified by GPs using the simple two-step diagnostic strategy described in Chapter 2, and were randomised to receive either primary care management led by their GP and a community-based nurse, or usual laboratory-based care in a specialist sleep centre. For the primary outcome, mean change in ESS at 6 months, primary care management was not inferior to specialist management (4.6 vs 5.1, adjusted difference -0.6 [lower bound 95% confidence interval: -1.8], p=0.37). There were no differences in secondary outcomes, including quality of life, OSA symptoms, treatment compliance and overall patient satisfaction. Within-study costs were lower in the primary care arm, with savings of AUD$2157 (95%CI: $1293 to $3114) per patient. A simplified model of care for the diagnosis and management of OSA based in the primary care setting is efficacious and cost-effective, and has the potential to reduce the burden of untreated OSA in the community.
Keywords: obstructive sleep apnea,primary care,portable monitoring,screening questionnaire,continuous positive airway pressure
Subject: Medicine thesis
Thesis type: Doctor of Philosophy
School: School of Medicine
Supervisor: Professor R Douglas McEvoy