Clinical characteristics and outcomes in adult cystic fibrosis patients with severe lung disease in Porto Alegre, southern Brazil

Background Advanced lung disease in adult cystic fibrosis (CF) drives most clinical care requirements. The aim was to evaluate outcome (time to death while in the study) in a cohort of adult CF patients with severe lung disease, and to determine the association among baseline patient characteristics and outcome. Methods A retrospective cohort study was performed and clinical records between 2000 and 2015 were reviewed. Severe lung disease was defined as forced expiratory volume in the first second (FEV1) < 30% of predicted. Outcomes of all patients, including their date of death or transplantation, were determined till January 1st, 2016. Clinical data were recorded at the entry date. Results Among 39 subjects included in the study, 20 (51.3%) died, 16 (41.0%) underwent bilateral lung transplantation, and 3 were alive at the end of the study period. Two variables were independently associated with death: body mass index (BMI ≥ 18.5 kg/m2) (HR = 0.78, 95% CI = 0.64–0.96 and p = 0.017) and use of tobramycin inhalation therapy (HR = 3.82, 95% CI = 1.38–10.6 and p = 0.010). Median survival was 37 (95% CI = 16.4–57.6) months. The best cut-off point for BMI was 18.5 kg/m2. Median survival in patients with BMI < 18.5 kg/m2 was 36 months (95% CI = 18.7–53.3). Conclusion Median survival of CF subjects with FEV1 < 30% was 37 months. BMI and tobramycin inhalation therapy were independently associated with death. Median survival in patients with BMI < 18.5 kg/m2 was significantly lower than in patients with BMI ≥ 18.5 kg/m2. The association of tobramycin inhalation with death was interpreted as confounding by severity (use was reserved for advanced lung disease)