Medline ® Abstracts for References 14,27,28

STUDY OBJECTIVES: To examine whether the initial benefit of weight loss on obstructive sleep apnea (OSA) severity at 1 year is maintained at 4 years.

DESIGN: Randomized controlled trial with follow-up at 1, 2, and 4 years.

SETTING: 4 Look AHEAD clinical centers.

PARTICIPANTS: Two hundred sixty-four obese adults with type 2 diabetes and OSA.

INTERVENTIONS: Intensive lifestyle intervention with a behavioral weight loss program or diabetes support and education.

MEASUREMENTS: Change in apnea-hypopnea index on polysomnogram.

RESULTS: The intensive lifestyle intervention group's mean weight loss was 10.7±0.7 (standard error), 7.4±0.7, and 5.2±0.7 kg at 1, 2, and 4 years respectively, compared to a less than 1-kg weight loss for the control group at each time (P<0.001). Apnea-hypopnea index difference between groups was 9.7±2.0, 8.0±2.0, and 7.7±2.3 events/h at 1, 2 and 4 years respectively (P<0.001). Change in apnea-hypopnea index over time was related to the amount of weight loss (P<0.0001) and intervention, independent of weight loss (P = 0.001). Remission of OSA at 4 years was 5 times more common with intensive lifestyle intervention (20.7%) than diabetes support and education (3.6%).

CONCLUSIONS: Among obese adults with type 2 diabetes and OSA, intensive lifestyle intervention produced greater reductions in weight and apnea-hypopnea index over a 4 year period than did diabetes support and education. Beneficial effects of intensive lifestyle intervention on apneahypopnea index at 1 year persisted at 4 years, despite an almost 50% weight regain. Effect of intensive lifestyle intervention on apnea-hypopnea index was largely, but not entirely, due to weight loss.

OBJECTIVE: To determine whether initial improvements in obstructive sleep apnoea after a very low energy diet were maintained after one year in patients with moderate to severe obstructive sleep apnoea.

DESIGN: Single centre, prospective observational follow-up study.

SETTING: Outpatient obesity clinic in a university hospital in Stockholm, Sweden.

PARTICIPANTS: 63 men aged 30-65 with body mass index (BMI) 30-40 and moderate to severe obstructive sleep apnoea defined as an apnoea-hypopnoea index≥15 (events/hour), all treated with continuous positive airway pressure.

INTERVENTION: A one year weight loss programme, consisting of an initial very low energy diet for nine weeks (seven weeks of 2.3 MJ/day and two weeks of gradual introduction of normal food) followed by a weight loss maintenance programme.

MAIN OUTCOME MEASURE: Apnoea-hypopnoea index, the main index for severity of obstructive sleep apnoea. Data from all patients were analysed (baseline carried forward for missing data).

RESULTS: Of 63 eligible patients, 58 completed the very low energy diet period and started the weight maintenance programme and 44 completed the full programme; 49 had complete measurements at one year. At baseline the mean apnoea-hypopnoea index was 36 events/hour. After the very low energy diet period, apnoea-hypopnoea index was improved by -21 events/hour (95% confidence interval -17 to -25) and weight by -18 kg (-16 to -19; both P<0.001). After one year the apnoea-hypopnoea index had improved by -17 events/hour (-13 to -21) and body weight by -12 kg (-10 to -14) compared with baseline (both P<0.001). Patients with severe obstructive sleep apnoea at baseline had greater improvements in apnoea-hypopnoea index (-25 events/hour) compared with patients with moderate disease (-7 events/hour, P<0.001). At one year, 30/63 (48%, 95% confidence interval 35% to 60%) no longer required continuous positive airway pressure and 6/63 (10%, 2% to 17%) had total remission of obstructive sleep apnoea (apnoea-hypopnoea index<5 events/hour). 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).

CONCLUSION: 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. Trial registration Current Controlled Trials 70090382.

BACKGROUND: Obesity is the most important risk factor for obstructive sleep apnea (OSA). Weight-reduction programs have been observed to represent effective treatment of overweight patients with OSA. However, it is not known whether beneficial changes remain after the end of the intervention.

OBJECTIVE: The aim of the study was to assess the long-term efficacy of a lifestyle intervention based on a healthy diet and physical activity in a randomized, controlled, 2-y postintervention follow-up in OSA patients.

DESIGN: Eighty-one consecutive overweight [body mass index (in kg/m(2)): 28-40]adult patients with mild OSA were recruited. The intervention group completed a 1-y lifestyle modification regimen that included an early 12-wk weight-reduction program with a very-low-calorie diet. The control group received routine lifestyle counseling. During the second year, no dietary counseling was offered. Change in the apnea-hypopnea index (AHI) was the main objective outcome variable, and changes in symptoms were used as a subjective measurement.

RESULTS: A total of 71 patients completed the 2-y follow-up. The mean (±SD) changes in diet and lifestyle with simultaneous weight reduction (-7.3±6.5 kg) in the intervention group reflected sustained improvements in findings and symptoms of OSA. After 2 y, the reduction in the AHI was significantly greater in the intervention group (P = 0.049). The intervention lowered the risk of OSA at follow-up; the adjusted odds ratio for OSA was 0.35 (95% CI: 0.12-0.97; P = 0.045).

CONCLUSION: Favorable changes achieved by a 1-y lifestyle intervention aimed at weight reduction with a healthy diet and physical activity were sustained in overweight patients with mild OSA after the termination of supervised lifestyle counseling. This trial was registered at clinicaltrials.gov as NCT00486746.