Long-term effect of weight loss on obstructive sleep apnea severity in obese patients with type 2 diabetes

Abstract

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.

Keywords: Apnea-hypopnea index; polysomnogram.

Figure 1

Diagram showing the number of Sleep AHEAD participants in the intensive lifestyle intervention and diabetes support and education groups who completed assessments over time. DSE, Diabetes Support and Education; FU, follow-up; ILI, intensive lifestyle intervention; OSA, obstructive sleep apnea; PSG, polysomnogram.

Figure 2

Estimated mean (standard error) changes in body weight and AHI from baseline at year 1, 2, and 4. AHI, apnea-hypopnea index (the number of apneahypopnea events/h). The dashed line indicates the Diabetes Support and Education group; the solid line indicates the Intensive Lifestyle Intervention group.

Figure 3

Percentage of participants in intensive lifestyle intervention (black bars, n = 90) and diabetes support and education (white bars, n = 97) whose obstructive sleep apnea (OSA) category improved (≥ 1 category change), worsened (≥ 1 category change), or was unchanged from baseline to year 4. Data are from the participants who had baseline and year 4 data.

Figure 4

Percentage of ILI (black bars) and DSE (white bars) participants without OSA and with mild, moderate, and severe OSA at 4 years compared to their OSA severity at baseline. DSE, Diabetes Support and Education; ILI, intensive lifestyle intervention.