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Obstructive Sleep Apnea May Be Improved With Low-Energy Diet

  • Authors: News Author: Laurie Barclay, MD
    CME Author: Charles P. Vega, MD
  • CME Released: 6/21/2011
  • Valid for credit through: 6/21/2012
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Target Audience and Goal Statement

This article is intended for primary care clinicians, pulmonary medicine specialists, endocrinologists, and other specialists who care for patients with obstructive sleep apnea.

The goal of this activity is to provide medical news to primary care clinicians and other healthcare professionals in order to enhance patient care.

Upon completion of this activity, participants will be able to:

  1. Describe short-term results of a diet intervention among men with obstructive sleep apnea.
  2. Evaluate the long-term effects of a diet intervention on men with obstructive sleep apnea.


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  • Laurie Barclay, MD

    Freelance writer and reviewer, Medscape, LLC


    Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.


  • Brande Nicole Martin

    CME Clinical Editor, Medscape, LLC


    Disclosure: Brande Nicole Martin has disclosed no relevant financial relationships.

CME Author(s)

  • Charles P. Vega, MD

    Associate Clinical Professor, Residency Program Director, Prime-LC, University of California-Irvine, Orange, California; Department of Family Medicine, University of California-Irvine, Orange, California


    Disclosure: Charles P. Vega, MD, has disclosed no relevant financial relationships.

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  • Sarah Fleischman

    CME Program Manager, Medscape, LLC


    Disclosure: Sarah Fleischman has disclosed no relevant financial relationships.

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Obstructive Sleep Apnea May Be Improved With Low-Energy Diet

Authors: News Author: Laurie Barclay, MD CME Author: Charles P. Vega, MDFaculty and Disclosures

CME Released: 6/21/2011

Valid for credit through: 6/21/2012


Clinical Context

Obstructive sleep apnea is more common among individuals with obesity, and the authors of the current study (Johansson and colleagues) previously reported on the short-term effects of a very low-energy diet intervention among men with obstructive sleep apnea. Their results, which were published in the December 3, 2009, issue of the BMJ, found that this diet yielded an average weight loss of 20 kg at 9 weeks vs the control group. Moreover, the apnea-hypopnea index was reduced by a mean of 23 events/hour in the diet group vs the control group. There were 17% of men in the diet group who became disease-free from obstructive sleep apnea by the end of the intervention.

The current study evaluates this study cohort after 1 year to determine whether the improvements documented with the very low-energy diet could be maintained with time.

Study Synopsis and Perspective

A very low-energy diet leads to improvements in moderate to severe obstructive sleep apnea in obese men, with benefits maintained at 1 year and proportional to weight loss and baseline severity, according to the results of a single-center, prospective, observational follow-up study reported online June 1 in the BMJ.

"Of all people with obstructive sleep apnea, an estimated 60-70% are either overweight or obese," write Kari Johansson, PhD student in the Obesity Unit, Department of Medicine at the Karolinska Institute in Stockholm, Sweden, and colleagues. "Given the close association between obstructive sleep apnoea and obesity, weight loss has been advocated as a primary treatment option in obese patients with sleep apnoea.... Despite an improving case for the robust treatment effect of weight loss in obstructive sleep apnoea, concerns remain regarding the long term maintenance of improvements, especially after rapid weight loss with a very low energy diet."

The goal of the study was to evaluate whether initial improvements in obstructive sleep apnea after a very low-energy diet were maintained after 1 year in patients with moderate to severe disease. At an outpatient obesity clinic in a university hospital in Stockholm, 63 men aged 30 to 65 years were enrolled. Body mass index was 30 to 40 kg/m2, and patients had moderate to severe obstructive sleep apnea treated with continuous positive airway pressure, with an apnea-hypopnea index of at least 15 events/hour (mean, 36 events/hour).

Participants were enrolled in a 1-year weight loss program in which they were given a very low-energy diet (2.3 MJ/day) for 7 weeks, followed by 2 weeks of gradual introduction of normal food and then by a weight loss maintenance program. The primary study endpoint was severity of obstructive sleep apnea as measured by the apnea-hypopnea index. Analysis was performed on all patient data, with baseline carried forward for missing data.

Of 63 patients enrolled, 58 completed the very low-energy diet and began the weight maintenance program, and 44 completed the full program. At 1 year, 49 patients had complete measurements. After completing the very low-energy diet period, participants had mean improvements of −21 events/hour in the apnea-hypopnea index (95% confidence interval [CI] −17 to −25) and −18 kg in weight (95% CI, −16 to −19; both < .001). After 1 year, improvement from baseline was −17 events/hour in the apnea-hypopnea index (95% CI, −13 to −21) and −12 kg in body weight (95% CI, −10 to −14; both P < .001).

Improvements in the apnea-hypopnea index were greater in patients with severe obstructive sleep apnea at baseline (−25 events/hour) vs patients with moderate disease (−7 events/hour, P < .001). At 1 year, continuous positive airway pressure was no longer needed in 30 of 63 patients (48%; 95% CI, 35% - 60%), and 6 patients (10%; 95% CI, 2% - 17%) had total remission of obstructive sleep apnea, defined as an apnea-hypopnea index of less than 5 events/hour.

Limitations of this study include observational design, lack of a control group, use of a portable diagnostic device instead of polysomnography to detect obstructive sleep apnea, lack of generalizability to women, and follow-up limited to 1 year.

"There was a dose-response association between weight loss and apnoea-hypopnoea index at follow-up (β=0.50 events/kg, 0.11 to 0.88; P=0.013)," the study authors write. "Initial improvements in obstructive sleep apnoea after treatment with a very low energy diet can be maintained after one year in obese men with moderate to severe disease. Those who lose the most weight or have severe sleep apnoea at baseline benefit most."

Cambridge Weight Plan, Northants, United Kingdom, and Novo Nordisk AS, Bagsværd, Denmark, supported this study. Some of the study authors have disclosed various financial relationships with Cambridge Weight Plan.

BMJ. 2011;342:d3017. Full text

Study Highlights

  • Men between the ages of 30 and 65 years who had a body mass index between 30 and 40 kg/m2 were eligible for study participation. All participants had moderate to severe obstructive sleep apnea treated with continuous positive airway pressure for at least 6 months.
  • The very low-energy diet consisted of a 2.3-MJ/day liquid diet for 7 weeks, followed by 2 weeks of gradual reintroduction of normal food to reach 6.3 MJ/day at week 9. The randomized trial lasted 9 weeks, at which time the control group participated in the very low-energy diet.
  • The weight maintenance program consisted of 3-hour group meetings once monthly. These sessions focused on diet and behavior. Weight gain was treated initially with meal replacement with a low-calorie food and secondarily with orlistat or sibutramine.
  • The primary outcome of the current study was the apnea-hypopnea index at week 52. These values were determined by the average of 2 sessions of home sleep study. Researchers also followed a measure of daytime sleepiness, anthropometric outcomes, and metabolic variables.
  • 63 men underwent randomization, and 58 began the weight maintenance program. 44 participants completed the full study protocol. The mean age of participants was 48.7 years, and the average body mass index was 34.8 kg/m2.
  • After crossing over at 9 weeks to receive the very low-energy diet, participants in the control group demonstrated similar improvements from baseline in body weight and the apnea-hypopnea index vs the intervention group from weeks 0 to 9.
  • 86% of men reported using meal replacements at least once during the weight maintenance phase, but weight gain was treated with orlistat only once.
  • At 1 year, the improvements in body weight were attenuated from 9 weeks but still improved from baseline (average weight loss from baseline at week 52, −12.1 kg; 95% CI, −9.8 to −14.3). The mean weight gain during the maintenance period was 5.6 kg, and the mean increase in waist circumference during this period was 3.2 cm.
  • The apnea-hypopnea index improved by an average of 17 events/hour between baseline and week 52 (95% CI, −13 to −21), and 10% (95% CI, 2% - 17%) of the study cohort had complete remission of obstructive sleep apnea.
  • There was a dose-response relationship between a lower apnea-hypopnea index and reductions in body weight, waist circumference, neck circumference, and percentage of body fat.
  • The apnea-hypopnea index improved to a greater degree with weight loss among men with severe obstructive sleep apnea vs those with moderate sleep apnea (average reductions of −25 vs −7 events/hour, respectively).
  • Daytime sleepiness improved modestly from baseline to week 52 in the study cohort.
  • A measurement of physical quality of life was improved at 52 weeks, but mental quality-of-life scores were stable during the study.
  • Half of the study cohort experienced resolution of insulin resistance during the 1-year study period, and the rate of resolution of the metabolic syndrome was 52%. However, mean blood pressure values were similar to baseline levels at week 52.
  • 21% of men receiving the very low-energy diet experienced an adverse event during the randomized trial, the most common of which was an increase in serum transaminase levels. The rate of adverse events decreased to 9% during the weight loss maintenance phase of the study. Gallstones developed in 3 participants, and another 3 participants experienced gout.

Clinical Implications

  • A previous randomized study of the current cohort demonstrated that initiation of a very low-energy diet was associated with a mean weight loss of 20 kg and a mean decrease of 23 events/hour on the apnea-hypopnea index vs a control diet. A total of 17% of men receiving the intervention were disease-free by week 9.
  • The current study demonstrates that both weight loss and improvements in the apnea-hypopnea index can be maintained for 1 year after a weight loss intervention. Men with severe obstructive sleep apnea in particular benefited from weight loss, and the very low-energy diet improved physical quality of life and multiple metabolic variables.

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