Blood pressure response to treatment of obese vs non-obese adults with sleep apnea

Level 2 Polysomnography for the Diagnosis of Sleep Disorders: A Health Technology Assessment

Background

It is estimated that half of Canadians have insufficient sleep, which over time is associated with poor physical and mental health. Currently, the only publicly funded option for the diagnosis of sleep disorders in Ontario is an in-person overnight sleep study, performed in a hospital or independent health facility (known as a level 1 polysomnography). Level 2 polysomnography has been proposed as an alternative that can be conducted at home for the diagnosis of suspected sleep disorders, if considered to have sufficient diagnostic accuracy. We conducted a health technology assessment of level 2 polysomnography for the diagnosis of suspected sleep disorders in adults and children, which included an evaluation of the test performance, cost-effectiveness, and budget impact of publicly funding level 2 polysomnography, and the experiences, preferences, and values of people with suspected sleep disorders.

Methods

We performed a systematic literature search of the clinical evidence to identify diagnostic accuracy, test failures and subjective measures of patient preferences. We assessed the risk of bias of each included study (using the Quality Assessment of Diagnostic Accuracy Studies [QUADAS-2] tool) and the quality of the body of evidence (according to Grading of Recommendations Assessment, Development, and Evaluation [GRADE] Working Group criteria). We performed a systematic literature search of economic evidence and conducted a primary economic evaluation and budget impact analysis to determine the cost-effectiveness and additional costs of publicly funding level 2 polysomnography for adults and children with suspected sleep disorders in Ontario. To contextualize the potential value of using level 2 polysomnography, we spoke with people with sleep disorders.

Results

We included 10 studies that reported on diagnostic accuracy and found level 2 polysomnography had sensitivity ranging between 0.76-1.0 and specificity ranging between 0.40-1.0 (GRADE: Moderate to Very low) when compared with level 1 polysomnography. Studies reported test failure rates from 0% to 20%, with errors present in both level 1 and level 2 tests conducted (GRADE: Very low). As well, some of these studies reported patients were found to have mixed opinions about their experiences, with more people preferring their experience with level 2 testing at home and having better quality of sleep compared with when they underwent level 1 testing (GRADE not conducted).Our primary economic evaluation showed that for adults with suspected sleep disorders, the new diagnostic pathway with level 2 polysomnography was equally effective (outcome: confirmed diagnosis at the end of the pathway) as the current practice diagnostic pathway with level 1 polysomnography. With the assumption of a lower technical fee for level 2 polysomnography, the new diagnostic pathway with level 2 polysomnography was less costly than the current practice diagnostic pathway (a saving of $27 per person with a wide 95% credible interval [95% CrI, -$137 to $121]), indicating that the results are highly uncertain. For children, a new diagnostic pathway with level 2 polysomnography was associated with additional costs (mean, $9.70; 95% CrI, -$125 to $190), and similarly, this estimate was highly uncertain.We estimated that the budget impact of publicly funding level 2 polysomnography for adults is uncertain and could range from savings of $22 million to additional costs of $43 million. Publicly funding a diagnostic pathway with level 2 polysomnography for children could result in additional costs of about $0.005 million over the next 5 years.People with whom we spoke reported that their sleep disorder negatively impacted their day-to-day lives, mental health, social and family relationships, and work. Participants who had experience with in-clinic (level 1) polysomnography described negative experiences they had at the clinic. Most people said they would prefer at-home (level 2) polysomnography over in-clinic (level 1) polysomnography, citing comfort and convenience as the main reasons; however, some people who have physical limitations preferred level 1 (in-clinic) polysomnography because they needed assistance to set up the equipment.

Conclusions

Level 2 polysomnography may have good test performance for adults and children, with adequate diagnostic accuracy, compared with level 1 polysomnography. The economic analyses showed that level 2 polysomnography for adults with suspected sleep disorders could be potentially cost saving but there is high uncertainty in the cost-effectiveness results. Given very limited information, the cost-effectiveness of this technology is also highly uncertain for children and young adults with suspected sleep disorders. The budget impact of publicly funding level 2 polysomnography for adults could range from savings of $22 million to additional costs of $43 million. Publicly funding level 2 polysomnography in children would require additional costs of about $0.005 million over the next 5 years. A clearer understanding of uptake of the technology, test costs, and the implementation pathway for adopting the technology is needed to improve the certainty of the cost-effectiveness and budget impact estimates. People with sleep disorders highlighted how important getting a diagnosis had been in order to be able to seek proper treatment for their sleep disorder and improve their lives. For many people with suspected sleep disorders, undergoing a sleep study at home would be a more comfortable and convenient option than undergoing a sleep study in clinic.

Obesity does not modify the effect of continuous positive airway pressure on insulin resistance in adults with obstructive sleep apnoea

This study found no evidence that obesity significantly modifies the effect of 4 months of CPAP treatment on HOMA-IR. Longer duration of CPAP treatment may be needed in order to reduce insulin resistance and determine whether obesity modifies the effect. https://bit.ly/3CtX7jZ.

Socioeconomic status impacts blood pressure response to positive airway pressure treatment

STUDY OBJECTIVES

Positive airway pressure (PAP) treatment of obstructive sleep apnea (OSA) reduces blood pressure (BP). Retrospective data suggest that African Americans (AA), a group at high-risk for hypertensive organ dysfunction, may have a greater BP response to PAP therapy than European Americans (EA). We examined the difference in 24-hour BP response to three months of PAP treatment between AA and EA.

METHODS

Participants (N=259, 161 AA and 98 EA) with apnea-hypopnea index (AHI) ≥15/hour from two prospective cohorts were included. T-tests and multiple linear regression were used to examine BP outcomes in AA vs. EA, adjusting for PAP adherence, socioeconomic status (SES), and baseline characteristics.

RESULTS

Participants were middle-aged (mean ± standard deviation, 53.8±9.3 years), 86% (227) men, AHI 35.6±19.2/hour, and PAP adherence of 3.36±2.24 hours/day. The reductions in 24-hour systolic and diastolic BP (mm Hg) were not different in AA vs. EA (systolic=-1.13±12.1 vs. -0.61±12.8, p=0.80 and diastolic=-0.74±7.9 vs. -0.80±7.4, p=0.96), and race was not a predictor of 24-hour systolic or diastolic BP reduction (p=0.75 and 0.54). SES and PAP adherence demonstrated a significant interaction; low SES was associated with an increase in 24-hour systolic BP (β=19.3, p=0.03) in the absence of PAP use but a greater reduction in 24-hour systolic BP with higher PAP adherence (β=-3.96, p=0.03).

CONCLUSIONS

24-hour BP response to PAP treatment is similar in AA and EA. Adherence to PAP treatment is more effective in improving 24-hour systolic BP in those with low SES.

The study was a clinical trial. Clinical Trial Registration: NCT01960465 and NCT01578031.

Racial Differences in Functional and Sleep Outcomes with Positive Airway Pressure Treatment

It is unclear if the response to positive airway pressure (PAP) treatment is different between African American (AA) and European Americans (EA). We examined whether race modifies the effects of PAP on sleep and daytime function. We assessed Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire, Psychomotor Vigilance Task and actigraphy in 185 participants with moderate-to-severe obstructive sleep apnea before and 3–4 months after PAP treatment. The participants were middle-aged (mean, 55.1 years), 83.8% men and 60.5% AA. Linear regression models were used to examine the effect of race on outcomes. The AA had smaller reductions in ESS (mean change (95% confidence interval, CI) AA, −2.30 [−3.35, −1.25] vs. EA, −4.16 [−5.48, −2.84] and frequency of awakenings (AA, −0.73 [−4.92, 3.47] vs. EA, −9.35 [−15.20, −3.51]). A race × PAP usage interaction term was added to the model to examine if the change in outcomes per 1 h increase in PAP usage differed by race. AA exhibited greater improvement in wake after sleep onset (β (95% CI) AA, −8.89 [−16.40, −1.37] vs. EA, 2.49 [−4.15, 9.12]) and frequency of awakening (β (95% CI) AA, −2.59 [−4.44, −0.75] vs. EA, 1.71 [−1.08, 4.50]). The results indicate the importance of race in evaluating outcomes following PAP treatment.

Changes in sleepiness and 24-h blood pressure following 4 months of CPAP treatment are not mediated by ICAM-1

OBJECTIVE

Continuous positive airway pressure (CPAP) therapy reduces circulating intercellular adhesion molecule 1 (ICAM-1) in adults with obstructive sleep apnea (OSA). ICAM-1 levels may affect the daytime sleepiness and elevated blood pressure associated with OSA. We evaluated the association of changes from baseline in ICAM-1 with changes of objective and subjective measures of sleepiness, as well as 24-h ambulatory blood pressure monitoring (ABPM) measures, following 4 months of CPAP treatment.

METHODS

The study sample included adults with newly diagnosed OSA. Plasma ICAM-1, 24-h ABPM, Epworth Sleepiness Scale (ESS), and psychomotor vigilance task (PVT) were obtained at baseline and following adequate CPAP treatment. The associations between changes in natural log ICAM-1 and changes in the number of lapses on PVT, ESS score, and 24-h mean arterial blood pressure (MAP) were assessed using multivariate regression models, controlling for a priori baseline covariates of age, sex, BMI, race, site, smoking status, physical activity, anti-hypertensive medications, AHI, and daily hours of CPAP use.

RESULTS

Among 140 adults (83% men), mean (± SD) body mass index (BMI) was 31.5 ± 4.2 kg/m², and apnea-hyopnea index (AHI) was 36.8 ± 15.3 events/h. Sleepiness measures, although not ICAM-1 or ABPM measures, improved significantly following CPAP treatment. We observed no statistically significant associations between the change in ICAM-1 and changes in sleepiness, MAP, or other ABPM measures.

CONCLUSION

Changes in ICAM-1 levels were not related to changes in sleepiness or ABPM following CPAP treatment of adults with OSA. Future work should explore whether or not other biomarkers may have a role in mediating these treatment outcomes in adults with OSA.

Effect of Obstructive Sleep Apnea and Positive Airway Pressure Therapy on Cardiac Remodeling as Assessed by Cardiac Biomarker and Magnetic Resonance Imaging in Nonobese and Obese Adults

It is unknown whether obesity modifies the effect of obstructive sleep apnea (OSA) and positive airway pressure (PAP) therapy on cardiac remodeling and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. We compared NT-proBNP and cardiac magnetic resonance imaging in adults without OSA (n=56) and nonobese (n=73; body mass index <30 kg/m²) and obese (n=136; body mass index ≥30 kg/m²) adults with OSA. We also investigated these traits in nonobese (n=45) and obese (n=78) participants with OSA adherent to 4 months of PAP treatment. At baseline, left ventricular mass to end-diastolic volume ratio, a measure of left ventricular concentricity, was greater in both nonobese and obese participants with OSA compared with those without OSA. Participants with OSA and obesity exhibited reduced phasic right atrial function. No significant differences in baseline NT-proBNP were observed across groups. The effect of PAP treatment on NT-proBNP and left atrial volume index was significantly modified by obesity. In nonobese participants, PAP therapy was associated with a decrease in NT-proBNP (P<0.0001) without a change in left atrial volume index, whereas in obese participants, PAP was associated with an increase in left atrial volume index (P=0.006) without a change in NT-proBNP. OSA was associated with left ventricular concentric remodeling independent of obesity and right atrial dysfunction in participants who were obese. PAP treatment was associated with reduced NT-proBNP in nonobese participants with OSA, but left atrial enlargement in obese participants with OSA, suggesting that PAP-induced reduction in BNP release (which is known to occur during obstructive apnea episodes) may lead to volume retention in obese participants with OSA. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01578031.