Influence of body mass index in the postoperative evolution after lung transplantation

To study the influence of body mass index (BMI) on mortality and postoperative evolution in our 10-year experience as a lung transplant group.

The study included 256 lung transplants performed between June 1999 and June 2009. BMI was stratified into 4 groups (<20 kg/m2 underweight, 20-25 normal weight, 25-30 overweight, and >30 obese) for posttransplant mortality assessment (chi-square) in relation to age, gender, pathology, and transplant type (logistic regression). Time of mechanical ventilation and length of stay in the intensive care unit and in the hospital were also analyzed (Kruskal-Wallis test).

BMI showed a normal distribution with a mean value of 24.8±5 kg/m2 (range, 13-38). Although postoperative mortality was greater in the overweight (23%) and obese (23.7%) groups, it did not reach statistical significance, nor was there a significant increase in the risk of death (odds ratios of 1.06 and 1.17, respectively). Risk of death was independent of BMI and was associated with pathology (lower in emphysema) and transplant type (lower in single lung). There were no significant differences in duration of mechanical ventilation (342 hours in obese patients vs 180 in normal weight; P=.7), length of stay in the intensive care unit (18 days in obese patients vs 14 in normal weight; P=.8), or length of hospital stay of patients that were discharged (37 days in obese patients vs 43 in normal weight; P=.8).

In our experience, BMI is not a risk factor that significantly increases postoperative mortality, probably owing to an adequate selection of recipients and an optimal posttransplant management. However, it must be considered to be a relative contraindication, because it is established in the international guidelines, obliging a correct assessment of patients, especially if there are other comorbidities.