Acceptability, adaptability and adherence to CPAP therapy among Aboriginal Australians with OSA - "The A5 study".

BACKGROUND: Studies examining how Australian Aboriginal people will accept, adapt and adhere to interventions such as continuous positive airway pressure (CPAP) therapy in the management of obstructive sleep apnoea (OSA) are sparsely reported. METHODS: In this study, clinical, demographic, polysomnographic (PSG) and CPAP data were utilised to assess and predict acceptance and adherence to CPAP therapy among adult Aboriginal Australians diagnosed to have OSA. RESULTS: Of the 649 Aboriginal patients with OSA, 49% accepted to trial CPAP therapy. Patients who accepted to trial CPAP showed more severe OSA (65vs.35% with severe OSA), reported higher daytime sleepiness (median 10vs.9), and had a higher BMI (83vs.73% obese). Of those who accepted to trial CPAP, 62% adapted to therapy (used the device for more than 30 days). Patients who adapted had more severe OSA (71vs.54% with severe OSA), and were more likely to live in urban areas (63vs.40%). Of those who adapted, 32% were adherent to therapy. Adherent patients were more likely to live in urban areas (84vs.53%), though there was no difference in OSA severity between adherent and non-adherent patients. In multivariate models remote location and more severe OSA predicted CPAP acceptance, while urban location and more severe OSA predicted adaptation, and urban location and higher oxygen saturation nadir predicted adherence. CONCLUSIONS: Acceptance to trial CPAP therapy was observed in the presence of symptomatic and severe OSA. However, long term adherence to CPAP therapy was significantly influenced by patients' residential location, with patients residing in remote/rural settings demonstrating significantly lower adherence rates.

Obstructive sleep apnea in aboriginal Australians: polysomnographic outcomes and symptom perception post-continuous positive airway pressure implementation.

Study Objectives: Obstructive sleep apnea (OSA) is reported to be highly prevalent among Aboriginal Australians. However, no studies have assessed the implementation and efficacy of continuous positive airway pressure (CPAP) therapy in this population. Hence, we compared the clinical, self-reported perception of sleep quality and polysomnographic (PSG) characteristics among Aboriginal patients with OSA. Methods: Adult Aboriginal Australians who underwent both diagnostic (Type 1 and 2) and in-lab CPAP implementation studies were included. Results: Total of 149 patients were identified (46% female, median age 49 years, body mass index 35 kg/m2). The OSA severity was 6% mild, 26% moderate, and 68% severe on the diagnostic PSG. On application of CPAP, there were significant improvements in; total arousal index (diagnostic 29 to 17/h on CPAP), total apnea-hypopnea index (AHI) (diagnostic 48 to 9/h on CPAP), non-rapid eye movement AHI (diagnostic 47 to 8/h on CPAP), rapid eye movement (REM) AHI (diagnostic 56 to 8/h on CPAP) and oxygen saturation (SpO2) nadir (diagnostic 77% to 85% on CPAP) (p < 0.001 for each). Following a single night of CPAP, 54% of patients reported sleeping "better than normal" compared to 12% following the diagnostic study (p = 0.003). In multivariate regression models, males had a significantly lesser change in REM AHI than females (5.7 events/hour less change (IQR 0.4, 11.1), p = 0.029). Conclusions: There is substantial improvement in several sleep-related domains on the application of CPAP among Aboriginal patients with a good initial acceptance of treatment. Whether the positive impact observed in this study translates to better sleep health outcomes with long-term adherence to CPAP therapy is yet to be assessed.

Comparison of diffusing capacity of carbon monoxide (DLCO) and total lung capacity (TLC) between Indigenous Australians and Australian Caucasian adults.

BACKGROUND AND OBJECTIVE: Currently there is paucity of evidence in the literature in relation to normative values for diffusing capacity of carbon monoxide (DLCO) and total lung capacity (TLC) among Indigenous Australians. Hence, in this study we assessed the DLCO and TLC parameters among Indigenous Australians in comparison to Australian Caucasian counterparts. METHODS: DLCO and TLC values were assessed and compared between Indigenous Australians and Australian Caucasians matched for age, sex and body mass index, with normal chest radiology. RESULTS: Of the 1350 and 5634 pulmonary function tests assessed in Indigenous Australian and Australian Caucasian adults respectively, a total of 129 Indigenous Australians and 197 Australian Caucasians met the inclusion criteria. Absolute DLCO and TLC values for Indigenous Australians were a mean 4.3 ml/min/mmHg (95% CI 2.86, 5.74) and 1.03 L (95% CI 0.78, 1.27) lower than Australian Caucasians (p<0.01). Percentage predicted values were 15.38 (95% CI 11.59, 19.17) and 16.63 (95% CI 13.59, 19.68) points lower for DLCO and TLC, respectively. Lower limit of normal (LLN) values did not significantly differ between groups, however a significantly greater proportion of Indigenous Australians recorded values below the LLN in comparison to Australian Caucasians for DLCO (64 vs. 25%, p<0.01) and TLC (66 vs. 21%, p<0.01). Significant differences for the interaction of sex on DLCO and TLC were noted in Australian Caucasians, with reduced or absent sex differentiation among Indigenous Australians. CONCLUSIONS: There are significant differences in DLCO and TLC parameters between Indigenous Australian compared to Australian Caucasians. Appropriate DLCO and TLC norms need to be established for Indigenous Australians.