Sleeping Well Trial: Increasing the effectiveness of treatment with continuous positive airway pressure using a weight management program in overweight adults with obstructive sleep apnoea-A stepped wedge randomised trial protocol

Body composition changes and their relationship with obstructive sleep apnoea symptoms, severity: The Sleeping Well Trial

BACKGROUND & AIMS

Obstructive sleep apnoea (OSA) and obesity share a complex bi-directional relationship as location of body fat and changes in regional body composition may be more important for OSA improvement than changes in total body weight only. The aim of this study was to evaluate the impact of a 6-month weight loss intervention for adults newly diagnosed with moderate-severe OSA and obesity on regional body composition. The secondary aims evaluated the relationship between changes in OSA symptoms and severity and anthropometry and regional body composition during the first 12-months after commencing CPAP and explored differences in outcomes between males and females.

METHODS

Participants (n = 59) received CPAP overnight at home alongside a 6-month modified fasting intervention with 12-months follow up. Regional body composition was measured by Dual X-ray absorptiometry, (DXA) and anthropometry before and after the lifestyle intervention. OSA severity was measured using the apnoea hypopnea index via overnight polysomnography and OSA symptoms were measured using the Epworth Sleepiness scale.

RESULTS

Forty-seven adults (74% male) had complete measures available with a mean age of 50.0 y (SD 11.0) and BMI 34.1 kg/m2 (SD 5.0). Following the intervention average fat mass changed by -5.27 kg (5.36), p < 0.001) and visceral adipose tissue (-0.63 kg (0.67), p < 0.001) significantly decreased in males only with a maintenance of fat-free mass (mean -0.41 kg (1.80), p = 0.18). Females (n = 12) had significant decreases in waist circumference (mean -3.36 cm (3.18) p < 0.01), android lean (-0.12 kg (0.04), p < 0.05) and android total mass (-0.28 kg (0.39), p < 0.05) only. Regional body composition changes in males were positively associated with improvements in OSA severity (p < 0.01) but not OSA symptoms.

CONCLUSION

Improvements in regional body composition were seen in males only which were related to improvements in OSA severity but not OSA symptoms. Females may exhibit different OSA pathophysiology and may require different treatment approaches.

TRIAL REGISTRATION

https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=369975&isReview=trueAACTRN12616000203459 ACTRN12616000203459.

Optimal allocation to treatment sequences in individually randomized stepped-wedge designs with attrition

BACKGROUND/AIMS

The stepped-wedge design has been extensively studied in the setting of the cluster randomized trial, but less so for the individually randomized trial. This article derives the optimal allocation of individuals to treatment sequences. The focus is on designs where all individuals start in the control condition and at the beginning of each time period some of them cross over to the intervention, so that at the end of the trial all of them receive the intervention.

METHODS

The statistical model that takes into account the nesting of repeated measurements within subjects is presented. It is also shown how possible attrition is taken into account. The effect of the intervention is assumed to be sustained so that it does not change after the treatment switch. An exponential decay correlation structure is assumed, implying that the correlation between any two time point decreases with the time lag. Matrix algebra is used to derive the relation between the allocation of units to treatment sequences and the variance of the treatment effect estimator. The optimal allocation is the one that results in smallest variance.

RESULTS

Results are presented for three to six treatment sequences. It is shown that the optimal allocation highly depends on the correlation parameter ρ and attrition rate r between any two adjacent time points. The uniform allocation, where each treatment sequence has the same number of individuals, is often not the most efficient. For 0 . 1 ≤ ρ ≤ 0 . 9 and r = 0 , 0 . 05 , 0 . 2 , its efficiency relative to the optimal allocation is at least 0.8. It is furthermore shown how a constrained optimal allocation can be derived in case the optimal allocation is not feasible from a practical point of view.

CONCLUSION

This article provides the methodology for designing individually randomized stepped-wedge designs, taking into account the possibility of attrition. As such it helps researchers to plan their trial in an efficient way. To use the methodology, prior estimates of the degree of attrition and intraclass correlation coefficient are needed. It is advocated that researchers clearly report the estimates of these quantities to help facilitate planning future trials.

Examining the relationship between obstructive sleep apnoea and eating behaviours and attitudes: A systematic review

BACKGROUND

Between 60 and 90% of adults with OSA are reported as overweight. The co-existence of obesity and OSA can greatly increase an individual's risk of type 2 diabetes, metabolic syndrome and cardiovascular disease. To better understand this relationship between OSA and weight, this review aimed to investigate if there is evidence of certain eating behaviours or eating attitudes that might be found in adults living with OSA.

METHODS

We searched four databases (MEDLINE, Embase, PsycInfo and Web of Science) on January 17th, 2022, to identify studies assessing the association between eating patterns and OSA in adults. Twenty-one studies met the inclusion criteria. A narrative synthesis was conducted on the included studies, following the vote-counting method.

RESULTS

There is preliminary evidence that the time of day when calories are consumed is associated with lower OSA severity. No other clear patterns of eating behaviours or attitudes were identified however this may be due to disparity within research studies and their reported results.

CONCLUSION

Further research is needed to examine the relationship between eating times and OSA severity. We recommend standardising the approach to examining the eating patterns of those living with OSA and the relationship that this might have on OSA symptoms as well as looking at attitudes towards food in this population. This may prove helpful in providing a better understanding of the relationship between OSA and persons with overweight and help in future intervention development.

A 12-month weight loss intervention in adults with obstructive sleep apnoea: is timing important? A step wedge randomised trial

BACKGROUND/OBJECTIVES

Continuous positive airway pressure (CPAP) concomitant with weight loss is a recommended treatment approach for adults with moderate-severe obstructive sleep apnoea (OSA) and obesity. This requires multiple synchronous behaviour changes. The aim of this study was to examine the effectiveness of a 6-month lifestyle intervention and to determine whether the timing of starting a weight loss attempt affects weight change and trajectory after 12 months in adults newly diagnosed with moderate-severe OSA and treated at home with overnight CPAP.

METHODS

Using a stepped-wedge design, participants were randomised to commence a six-month lifestyle intervention between one and six-months post-enrolment, with a 12-month overall follow-up. Adults (n = 60, 75% males, mean age 49.4 SD 10.74 years) newly diagnosed with moderate-severe OSA and above a healthy weight (mean BMI 34.1 SD 4.8) were recruited.

RESULTS

After 12 months, exposure to the intervention (CPAP and lifestyle) resulted in a 3.7 (95% CI: 2.6 to 4.8, p < 0.001) kg loss of weight compared to the control condition (CPAP alone). Timing of the weight loss attempt made no difference to outcomes at 12 months. When exposed to CPAP only (control period) there was no change in body weight (Coef, [95% CI] 0.03, [-0.3 to 0.36], p = 0.86).

CONCLUSIONS

The lifestyle intervention resulted in a modest reduction in body weight, while timing of commencement did not impact the degree of weight loss at 12 months. These findings support the recommendation of adjunctive weight-loss interventions within six-months of starting CPAP.

The impact of positive airway pressure on midface growth: a literature review

Introduction

The treatment of obstructive sleep apnea with positive airway pressure in children is restricted due to concerns that it could affect maxilla growth over time.

Objective

To undertake a systematic review of the literature about the long-term impact of using a positive airway pressure mask on the midface in growing individuals.

Methods

The literature search was conducted in September 2019 using the keywords (“long-term” OR “long term” OR “side effects” OR longitudinal) AND (children OR child OR preschool OR adolescents OR adolescent OR infant OR infants) AND (craniofacial OR “mid-face” OR midface OR midfacial OR facial OR maxillary) AND (“airway pressure” OR ventilation) in the databases PubMed, Web of Science and Lilacs. The search included papers published in English, until September 2019, on the effects of positive airway pressure on midfacial growth.

Results

The search strategy identified five studies: two case reports, two cross-sectional studies and one retrospective cohort study. All studies evaluated the long-term effects of a using a nasal mask on the midface in children and adolescents; four showed midface hypoplasia and one no showed difference post- treatment compared to a control.

Conclusion

Most of the studies demonstrated that long-term use of nasal positive airway pressure in childhood/adolescence is associated with midface hypoplasia.