Table 2.
Within-group changes and between-group differences in polysomnographic data.
| WS/GG (n = 43) | P a | < 5%WLG (n = 38) | P a | 5%–10% WLG (n = 52) | P a | ≥ 10%WLG (n = 47) | P a | P b | |
|---|---|---|---|---|---|---|---|---|---|
| AHI, events/h | |||||||||
| Baseline | 56 (25, 80) | .488 | 57 (31, 80) | < .001 | 61 (29, 82) | < .001 | 59 (28, 84) | < .001 | .587 |
| 6 months | 54 (29, 75) | 45 (27, 62) | 33 (20, 49) | 23 (15, 40) | < .001 | ||||
| %Δ | −0.50 (−11.1, 16.7) | −11.7 (−32.3, −2.78) | −37.9 (−43.5, −14.7) | −49.3 (−72.3, −34.1) | < .001 | ||||
| NREM-AHI, events/h | |||||||||
| Baseline | 55 (31, 81) | .402 | 54 (31, 74) | .023 | 56 (31, 84) | < .001 | 58 (33, 82) | < .001 | .494 |
| 6 months | 56 (37, 74) | 40 (26, 63) | 27 (19, 43) | 20 (12, 46) | .004 | ||||
| %Δ | 1.40 (−10.5, 17.3) | −8.11 (−34.1, 16.6) | −34.7 (−58.4, −16.81) | −48.0 (−75.5, −29.1) | < .001 | ||||
| REM-AHI, events/h | |||||||||
| Baseline | 63 (31, 94) | .253 | 62 (33, 90) | .004 | 65 (25, 78) | .002 | 64 (30, 95) | < .001 | .905 |
| 6 months | 53 (32, 60) | 45 (17, 64) | 36 (23, 53) | 27 (8, 43) | .045 | ||||
| %Δ | −8.11 (−36.0, 31.7) | −25.4 (−52.7, 26.8) | −38.3 (−74.6, 1.84) | −52.5 (−58.8, −23.63) | .007 | ||||
| AI, events/h | |||||||||
| Baseline | 38 (11, 62) | .481 | 39 (14, 65) | .026 | 44 (15, 70) | < .001 | 42 (14, 65) | < .001 | .209 |
| 6 months | 35 (13, 58) | 28 (14, 37) | 20 (10, 35) | 13 (5, 30) | .122 | ||||
| %Δ | −10.8 (−31.1, 86.6) | −18.5 (−48.7, 32.0) | −42.1 (−66.1, −13.2) | −51.6 (−80.3, −26.1) | < .001 | ||||
| HI, events/h | |||||||||
| Baseline | 16 (8, 25) | .469 | 18 (9, 27) | .898 | 13 (5, 22) | .672 | 14 (8, 22) | .087 | .206 |
| 6 months | 20 (13, 23) | 19 (12, 26) | 12 (10, 20) | 8 (4, 11) | < .001 | ||||
| %Δ | 15.9 (−48.3, 82.5) | 17.1 (−47.3, 98.4) | −3.02 (−44.5, 27.3) | −23.9 (−65.1, 37.8) | .570 | ||||
| ODI, events/h | |||||||||
| Baseline | 49 (27, 64) | .450 | 48 (17, 74) | .029 | 53 (23, 72) | < .001 | 54 (20, 73) | < .001 | .671 |
| 6 months | 47 (24, 51) | 35 (21, 49) | 26 (14, 41) | 16 (7, 40) | .002 | ||||
| %Δ | −6.28 (−24.9, 21.4) | −21.0 (−44.4, 43.6) | −42.9 (−60.3, −22.0) | −63.6 (−75.1, −39.7) | < .001 | ||||
| Minimum SaO2, % | |||||||||
| Baseline | 81 (76, 84) | .155 | 82 (76, 86) | .005 | 81 (72, 86) | < .001 | 78 (71, 85) | < .001 | .414 |
| 6 months | 83 (78, 84) | 84 (79, 86) | 84 (80, 87) | 83 (79, 88) | .403 | ||||
| %Δ | 1.19 (−2.41, 6.04) | 2.47 (−0.24, 7.32) | 4.53 (0.22, 11.4) | 6.02 (1.16, 12.7) | .031 | ||||
| SaO2 < 90%, % TSP | |||||||||
| Baseline | 3.66 (1.11, 10.0) | .372 | 4.00 (0.77, 7.32) | .042 | 3.98 (0.81, 10.8) | .001 | 4.29 (0.80, 8.99) | < .001 | .942 |
| 6 months | 3.40 (0,74, 11.5) | 3.18 (0.73, 6.53) | 2.60 (0.31, 4.59) | 1.85 (0.03, 3.00) | .007 | ||||
| %Δ | 3.63 (−27.3, 30.1) | −11.1 (−26.6, 17.6) | −45.6 (−75.0, 6.99) | −69.7 (−97.5, −20.1) | < .001 | ||||
Variables are presented as median (1st, 3rd quartile). Analyses were performed in the intention-to-treat population (n = 180). aP value for changes within groups, as derived from the Wilcoxon signed-rank test. bP value for differences between weight-change groups, as derived from the Kruskal-Wallis signed-rank-test. a,bP values < .050 indicate statistically significant results. %Δ = percent change, AHI = apnea-hypopnea index, AI = apnea index, HI = hypopnea index; NREM = nonrapid eye movement, ODI = oxygen desaturation index, REM = rapid eye movement, SaO2 = oxygen saturation, TSP = total sleep period, WLG = weight-loss group, WS/GG = weight-stable/gain group.