Demographics of the study population
| NBS+A | BS+A | BS−A | p Value | |
|---|---|---|---|---|
| Number | ||||
| Baseline | 12 | 27 | 39 | |
| 3-month follow-up | 11 | 26 | 33 | |
| 6-month follow-up | 11 | 21 | 34 | |
| 12-month follow-up | 12 | 27 | 39 | |
| Gender (% female) | 91.7% | 74.1 | 82.1 | 0.494 |
| Ethnicity (% non-Caucasian) | 25.0% | 14.8% | 15.4% | 0.714 |
| Age (years) | 33 (20–45) | 36 (19–48) | 39 (18–50) | 0.440 |
| Weight (kg) | 103 (82–132) | 130 (101–202) | 126 (94–199) | 0.044 |
| Body mass index (kg/m2) | 35.6 (30.9–53.9) | 45.1 (38.4–63.8) | 43.1 (35.6–58.6) | 0.015 |
| Abdominal circumference (cm) | 119 (102–155) | 133 (112–165) | 127 (103–200) | 0.016 |
| Smoking status | 0.178 | |||
| % never smoked | 75.0% | 55.6% | 71.8% | |
| % stopped smoking | 16.7% | 11.1% | 17.9% | |
| % current smoker | 8.3% | 33.3% | 10.3% | |
| Pack years | 0 (0–0) | 0 (0–10) | 0 (0–10) | 0.311 |
| Asthma | ||||
| Asthma Control Questionnaire* | 1.7 (0.3–2.6) | 1.1 (0.4–2.9) | 0.3 (0–2.9) | <0.001 |
| Asthma Quality of Life Questionnaire† | 5.4 (3.5–6.7) | 5.6 (3.7–6.8) | 6.5 (3.7–7.0) | 0.007 |
| Lung function | ||||
| Spirometry | ||||
| FEV1, pre (% predicted) | 88 (45–106) | 86 (66–119) | 97 (73–125) | 0.009 |
| FEV1, post (% predicted) | 95 (49–106) | 93 (75–118) | 101 (75–129) | 0.079 |
| FVC, pre (% predicted) | 102 (64–118) | 97 (75–126) | 106 (77–144) | 0.575 |
| FVC, post (% predicted) | 107 (62–120) | 99 (74–126) | 107 (78–141) | 0.754 |
| FEV1/FVC, pre (%) | 79 (61–90) | 76 (63–92) | 81 (66–93) | 0.096 |
| FEV1/FVC, post (%) | 82 (69–91) | 79 (67–94) | 84 (68–94) | 0.215 |
| RV, post (% predicted)‡ | 79.5 (74–92) | 74 (39–126) | 74 (47–118) | 0.567 |
| TLC, post (% predicted)‡ | 92.5 (77–109) | 98 (83–106) | 95 (75–114) | 0.826 |
| FRC, post (% predicted)‡ | 68 (54–90) | 62 (40–95) | 64 (41–88) | 0.554 |
| RV/TLC, post (%)‡ | 26.5 (20–36) | 22 (10–41) | 24 (12–41) | 0.146 |
| Reversibility FEV1 | 7 (−12–22) | 9 (-6–20) | 4 (-7–11) | 0.012 |
| FeNO (ppb) | 17 (7–96) | 16 (5–45) | 16 (7–53) | 0.870 |
| Diffusion capacity, kCO (% predicted) | 98 (70–116) | 97 (69–133) | 95 (69–134) | 0.890 |
| PD20 (mg) | 0.31 (0.04–1.8) | 0.37 (0.04–1.8) | 1.8 (1.8–1.8) | |
| IOS | ||||
| R5 (kPa/s) | 0.58 (0.24–1.11) | 0.69 (0.41–1.39) | 0.57 (0.17–0.97) | 0.022 |
| R20 (kPa/s) | 0.44 (0.20–0.65) | 0.45 (0.27–1.03) | 0.43 (0.18–0.68) | 0.841 |
| R5–R20 (kPa/s) | 0.18 (0.04–0.62) | 0.25 (0.06–0.66) | 0.17 (-0.1–0.48) | 0.001 |
| X5 (kPa/s) | −0.16 (−0.67 to −0.1) | −0.26 (0.87 to −0.12) | −0.21 (−0.43 to −0.10) | 0.138 |
| Fres (Hz) | 17.3 (9.2–30.4) | 22.6 (10.7–28.9) | 18.5 (8.4–28.7) | 0.001 |
Data are presented as median (min–max).
*Scores of the Asthma Control Questionnaire range from 0 to 6, with lower scores indicating better asthma control.
†Scores of the Asthma Quality of Life Questionnaire range from 1 to 7, with higher scores indicating better asthma-specific quality of life. ‡Because of weight limitations for the body box (<150 kg), full spirometry could not be performed in all subjects; numbers for these parameters: NBS+A=4, BS+A=15, BS−A=30.
BS+A, bariatric surgery and asthma group; BS−A, bariatric surgery without asthma group; FeNO, exhaled nitric oxide; FRC, functional residual capacity; IOS, impulse oscillometry; NBS+A, no bariatric surgery and asthma group; PD20, provocative dose of methacholine inducing a 20% fall in FEV1; RV, residual volume; TLC, total lung capacity.