Body mass index as a predictor of survival in adults with cystic fibrosis referred for lung transplantation

Background: The timing of referral and listing for lung transplantation in adults with cystic fibrosis is influenced by many factors including pulmona ry function, body mass index (BMI), sex, and patient and physician choice. This study aimed to analyze the effect of these variables on waiting list a nd postoperative mortality rates. In particular, low BMI is suggested to po rtend a poor outcome after transplantation Methods: All patients with cystic fibrosis referred to our institution (n = 92) between 1989 and 1996 were reviewed, and the effect on survival of BMI , sex, and other covariates was analyzed by use of Cox proportional hazards regression. Results: Forty-five transplantations were undertaken with a mean waiting ti me of 226 days (range 1 to 678). Fifteen of the 62 listed patients died bef ore transplantation with a mean time to death of 160 days (range 8 to 533). Fifteen patients died after transplantation. BMI at the time of listing pr edicted waiting List mortality (P <.05). Female sex tended to increase wait ing list mortality rates, such that the combination of BMI less than 18 kg/ m(2), and female sex was associated with a 21% 1-year waiting list survival without transplantation. Age, forced expiratory volume in 1 second, sex, B MI, and date of transplantation did not predict postoperative survival. Conclusion: Patients with cystic fibrosis (particularly women) referred for lung transplantation with a BMI less than 18 kg/m(2) are at high risk of d eath over the next 12 months. With this in mind, they should not be denied transplantation unduly while attempts are made to increase weight, especial ly because pretransplantation BMI does not influence posttransplantation su rvival.