TABLE 2.
ASSOCIATIONS BETWEEN BODY MASS INDEX AND THE RISK OF DEATH AFTER LUNG TRANSPLANTATION
| Body Mass Index Category |
|||||
|---|---|---|---|---|---|
| Underweight | Normal Weight | Overweight | Obese | P Value | |
| No. transplanted | 862 | 2,864 | 1,644 | 608 | |
| Median follow-up time, years | 4.1 | 4.5 | 4.1 | 3.7 | |
| Person-years | 3,760 | 13,041 | 6,640 | 2,336 | |
| Overall mortality | |||||
| Mortality rate per 100 person-years (95% CI) | 15.6* (14.4 to 17.0) | 14.0 (13.4 to 14.7) | 17.1† (16.1 to 18.1) | 18.4† (16.7 to 20.2) | <0.001 |
| Hazard ratios for death (95% CI) | |||||
| Model 1 | 1.16† (1.04 to 1.29) | 1.0 | 1.14† (1.05 to 1.24) | 1.20† (1.06 to 1.36) | <0.001 |
| Model 2 | 1.16† (1.04 to 1.29) | 1.0 | 1.15† (1.06 to 1.25) | 1.22† (1.07 to 1.38) | <0.001 |
| Model 3 | 1.15* (1.03 to 1.28) | 1.0 | 1.17† (1.07 to 1.27) | 1.25† (1.10 to 1.42) | <0.001 |
| Model 4 | 1.15* (1.03 to 1.28) | 1.0 | 1.15† (1.06 to 1.26) | 1.22† (1.08 to 1.39) | <0.001 |
| Death 1 year after transplantation | |||||
| No. with 1-year follow-up | 860 | 2,848 | 1,633 | 605 | |
| Risk of death at 1 year (95% CI) | 21.1%* (20.6 to 21.7%) | 17.7% (17.4 to 17.9%) | 22.8%† (22.3 to 23.2%) | 25.2%† (24.4 to 26.1%) | |
| Odds ratios for death at 1 year (95% CI) | |||||
| Model 1 | 1.37† (1.12 to 1.68) | 1.0 | 1.21* (1.03 to 1.42) | 1.29* (1.03 to 1.60) | 0.004 |
| Model 2 | 1.37† (1.12 to 1.68) | 1.0 | 1.23* (1.05 to 1.44) | 1.32* (1.06 to 1.64) | 0.002 |
| Model 3 | 1.34† (1.09 to 1.64) | 1.0 | 1.26† (1.07 to 1.48) | 1.38† (1.10 to 1.73) | 0.001 |
| Model 4 | 1.34† (1.09 to 1.64) | 1.0 | 1.27† (1.08 to 1.49) | 1.40† (1.11 to 1.75) | 0.001 |
| Death 5 years after transplantation conditional on 1-year survival | |||||
| No. with 5-year follow-up | 806 | 2,592 | 1,491 | 553 | |
| No. of 1-year survivors with 5-year follow-up | 626 | 2,088 | 1,118 | 401 | |
| Risk of death at 5 years (95% CI) | 54.0%† (52.2 to 55.9%) | 49.2% (48.3 to 50.1%) | 54.8%† (53.4 to 56.1%) | 60.1%† (57.7 to 62.5%) | |
| Risk of death at 5 years conditional on 1-year survival (95% CI) | 41.9%* (40.3 to 43.5%) | 38.3% (37.6 to 39.1%) | 41.4% (40.3 to 42.6%) | 46.7%† (44.5 to 49.0%) | |
| Odds ratios for death at 5 years conditional on 1-year survival (95% CI) | |||||
| Model 1 | 1.26* (1.04 to 1.53) | 1.0 | 1.04 (0.89 to 1.21) | 1.32* (1.06 to 1.66) | 0.02 |
| Model 2 | 1.25* (1.03 to 1.52) | 1.0 | 1.03 (0.89 to 1.21) | 1.33* (1.06 to 1.67) | 0.02 |
| Model 3 | 1.23* (1.01 to 1.50) | 1.0 | 1.05 (0.90 to 1.22) | 1.35† (1.08 to 1.62) | 0.02 |
| Model 4 |
1.22* (1.01 to 1.49) |
1.0 |
1.04 (0.89 to 1.22) |
1.29* (1.02 to 1.63) |
0.07 |
Definition of abbreviation: CI = confidence interval.
Odds ratios are from generalized additive models with loess smoothers for continuous covariates. Hazards ratios are from Cox models without smoothers. Odds ratios are adjusted for recipient transplant procedure (double vs. single) and diagnosis (cystic fibrosis, chronic obstructive pulmonary disease, diffuse parenchymal lung disease). Cox models include strata for transplant procedure, diagnosis, center, and transplant year. P values are from likelihood ratio tests comparing each model with a model that does not include body mass index categories.
Model 1: Adjusted for recipient characteristics (age, sex, height, and diagnosis), transplant procedure, and transplant year. Cox models are also adjusted for transplant center.
Model 2: Model 1 + adjustment for donor characteristics (age, sex, height, body mass index, pulmonary infection, smoking >20 pack-years, and donor cause of death).
Model 3: Model 2 + lung allocation score at the time of transplantation.
Model 4: Model 3 + cardiovascular risk factors (hypertension, smoking status, diabetes mellitus), hospitalization at transplant, cytomegalovirus mismatch status, HLA mismatch, use of steroids before transplant, graft ischemic time.
Wald test P < 0.05 compared with normal weight.
Wald test P < 0.01 compared with normal weight.