Table 4.
Baseline characteristics according to maximum WL categories for patients undergoing BS in the observational study cohort
| Maximum WL within 1 year postsurgery, % body weight | ||||||
|---|---|---|---|---|---|---|
| <20% | 20 to <30% | 30 to <40% | ≥40% | Missing value, n | P | |
| Participants, n | 426 | 1,894 | 2,184 | 833 | ||
| Age, years | ||||||
| Mean (SD) | 48.81 (9.62) | 47.35 (10.28) | 45.58 (10.10) | 43.41 (9.66) | 0 | <0.0001 |
| Median (IQR) | 50 (42–56) | 48 (40–55) | 46 (38–53) | 43 (37–50) | <0.0001 | |
| Sex, n (% female) | 330 (77.5) | 1,531 (80.8) | 1,865 (85.4) | 739 (88.7) | <0.0001 | |
| Income quintile, n (%) | ||||||
| 1 | 101 (23.7) | 428 (22.6) | 509 (23.3) | 184 (22.1) | 14 | 0.047 |
| 2 | 79 (18.5) | 439 (23.2) | 513 (23.5) | 183 (22.0) | ||
| 3 | 97 (22.8) | 424 (22.4) | 419 (19.2) | 201 (24.1) | ||
| 4 | 76 (17.8) | 346 (18.3) | 435 (19.9) | 158 (19.0) | ||
| 5 | 72 (16.9) | 255 (13.5) | 298 (13.6) | 106 (12.7) | ||
| Rural residence, n (%) | ||||||
| No | 375 (88.0) | 1,640 (86.6) | 1,819 (83.3) | 692 (83.1) | 0 | 0.003 |
| Yes | 51 (12.0) | 254 (13.4) | 365 (16.7) | 141 (16.9) | ||
| Baseline BMI, kg/m2 | ||||||
| Mean (SD) | 48.32 (8.21) | 48.95 (8.25) | 48.92 (7.57) | 50.68 (7.88) | 9 | <0.0001 |
| Median (IQR) | 47 (42–53) | 47 (43–54) | 48 (43–53) | 49 (45–55) | <0.0001 | |
| Diabetes, n (%) | ||||||
| No | 193 (45.3) | 969 (51.2) | 1,363 (62.4) | 585 (70.2) | 0 | <0.0001 |
| Yes | 233 (54.7) | 925 (48.8) | 821 (37.6) | 248 (29.8) | ||
| Hypertension, n (%) | ||||||
| Missing data | 3 (0.7) | 4 (0.2) | 3 (0.1) | 0 (0.0) | 10 | <0.0001 |
| No | 172 (40.4) | 871 (46.0) | 1,125 (51.5) | 478 (57.4) | ||
| Yes | 251 (58.9) | 1,019 (53.8) | 1,056 (48.4) | 355 (42.6) | ||
| Hyperlipidemia, n (%) | ||||||
| Missing data | 4 (0.9) | 4 (0.2) | 4 (0.2) | 2 (0.2) | 14 | <0.0001 |
| No | 237 (55.6) | 1,143 (60.3) | 1,458 (66.8) | 599 (71.9) | ||
| Yes | 185 (43.4) | 747 (39.4) | 722 (33.1) | 232 (27.9) | ||
| Vascular composite, n (%) | ||||||
| Missing data | 4 (0.9) | 5 (0.3) | 3 (0.1) | 2 (0.2) | 14 | 0.0292 |
| No | 370 (86.9) | 1,716 (90.6) | 1,976 (90.5) | 761 (91.4) | ||
| Yes | 52 (12.2) | 173 (9.1) | 205 (9.4) | 70 (8.4) | ||
| Baseline serum creatinine, μmol/L | ||||||
| Mean (SD) | 68.57 (15.46) | 66.06 (13.37) | 65.73 (12.89) | 65.53 (12.60) | 0 | 0.0004 |
| Median (IQR) | 67 (58–76) | 65 (57–74) | 65 (57–72) | 64 (57–72) | 0.0066 | |
| Baseline eGFR, mL/min/1.73 m2 | ||||||
| Mean (SD) | 98.27 (16.79) | 101.36 (15.40) | 102.26 (15.32) | 103.15 (15.52) | 0 ≥ | <0.0001 |
| Median (IQR) | 101 (88–110) | 104 (91–113) | 105 (94–113) | 106 (93–115) | <0.0001 | |
| Days from baseline creatinine measurement to surgery | ||||||
| Mean (SD) | 111.30 (107.40) | 118.13 (108.33) | 133.76 (110.07) | 146.44 (110.78) | <0.0001 | |
| Median (IQR) | 64 (19–190) | 79 (21–211) | 115 (26–229) | 143 (32–240) | <0.0001 | |
Cox proportional hazards models were fit for each primary and secondary outcome, adjusting for the baseline characteristics and baseline eGFR. Multiple imputation was used to impute missing values. ANOVA tests were used for continuous variables, and χ2 tests were used for categorical variables.