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

Abstract

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).