TABLE 5.
Preoperative BMI Odds Ratios for Successful Weight Loss Associated With Gastric Bypass and Gastric Band
| Prospective Month | Gastric Bypass (n = 958) | Gastric Band (n = 560) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| N (%) ≥40% EWL | N (%) <40% EWL | Successful Weight Loss* | N (%) ≥40% EWL | N (%) <40% EWL | Successful Weight Loss* | |||||||
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| Odds Ratio† | 95% CI for Odds Ratio | χ2 | P | Odds Ratio† | 95% CI for Odds Ratio | χ2 | P | |||||
| Month 6 | 0.12 | 0.08–0.18 | 136.25 | 0.0003 | 0.13 | 0.06–0.29 | 40.25 | 0.0001 | ||||
| Preop. BMI >50 | 258 (28.7%) | 158 (17.6%) | 7 (1.3%) | 174 (32.3%) | ||||||||
| Preop. BMI ≤50 | 449 (50.0%) | 33 (3.7%) | 84 (15.6%) | 273 (50.8%) | ||||||||
| Month 12 | 0.42 | 0.21–0.81 | 6.87 | 0.0147 | 0.29 | 0.18–0.47 | 29.35 | 0.0001 | ||||
| Preop. BMI >50 | 273 (42.0%) | 27 (4.2%) | 34 (8.5%) | 107 (26.7%) | ||||||||
| Preop. BMI ≤50 | 336 (51.7%) | 14 (2.1%) | 134 (33.4%) | 126 (31.4%) | ||||||||
| Month 18 | 0.51 | 0.21–1.24 | 2.27 | 0.1641 | 0.31 | 0.19–0.52 | 21.76 | 0.0001 | ||||
| Preop. BMI >50 | 184 (44.7%) | 14 (3.4%) | 41 (14.2%) | 72 (24.9%) | ||||||||
| Preop. BMI ≤50 | 206 (50.0%) | 8 (1.9%) | 113 (39.1%) | 63 (21.8%) | ||||||||
| Month 24 | 0.66 | 0.24–1.80 | 0.64 | 0.4228 | 0.43 | 0.24–0.78 | 7.7 | 0.0055 | ||||
| Preop. BMI >50 | 122 (45.7%) | 10 (3.8%) | 37 (18.1%) | 38 (18.6%) | ||||||||
| Preop. BMI ≤50 | 128 (47.9%) | 7 (2.6%) | 89 (43.7%) | 40 (19.6%) | ||||||||
| Overall (months 6–24) | 0.23 | 0.15–0.36 | 49.04 | 0.0003 | 0.34 | 0.22–0.51 | 28.52 | 0.0001 | ||||
| Preop. BMI >50 | 349 (36.4%) | 91 (9.5%) | 36 (6.4%) | 154 (27.5%) | ||||||||
| Preop. BMI ≤50 | 488 (50.9%) | 30 (3.1%) | 151 (27.0%) | 219 (39.1%) | ||||||||
The total evaluable sample (at the outset of postoperative follow-up) consisted of 1518 patients.
BMI measured in kg/m2.
Successful weight loss was a binomial variable defined as ≥40% EWL at each prospective study period for individual patients and unsuccessful weight loss was defined as <40% EWL.
Odds ratios were estimated from the corresponding 2 independent proportions (preoperative BMI group vs. successful/unsuccessful EWL) and represented the odds of successful weight loss for the preoperative BMI >50 group versus the preoperative BMI ≤50 group.
EWL indicates excess weight loss; overall, 24-month average; 95% CI, 95% confidence interval for the estimated odds ratio; χ2, likelihood ratio χ2 test statistic associated with the estimated odds ratio; P, P value associated with an upper one-tailed test; P values for the χ2 test are adjusted using the false discovery rate; N = sample size per group.