Body Weight and Body Mass Index in Patients with End-Stage Cystic Fibrosis Stabilize After the Start of Enteral Tube Feeding

Background: Enteral tube feeding (ETF) is widely used in patients with cystic fibrosis (CF) and end-stage lung disease, but previous studies have been limited to investigating whether ETF improves outcomes in patients with moderately or mildly impaired pulmonary function.

Objective: This study investigated body weight, body mass index (BMI; calculated as kg/m²), pulmonary function, and the presence of CF-related diabetes before and after the start of ETF.

Design: This was a retrospective observational study.

Participants/setting: Data from 26 adult patients in an outpatient setting who had end-stage CF (19 women) and had been using ETF for at least 6 months between 2000 and 2014 were analyzed.

Main outcome measures: Body weight, BMI, pulmonary function (forced expiratory volume in 1 second as percent of predicted) and incidence of CF-related diabetes from 6 months before to 6 months after starting ETF.

Statistical analyses performed: Time effects were tested with one-way analysis of variance for data that were normally distributed and the Friedman test for non-parametric data. Correlations were tested with Pearson's r or Spearman's ρ, depending on the distribution of the data.

Results: Mean body weight increased by 3.5 kg (95% CI 2.2 to 4.8 kg) after patients started ETF. In women, mean BMI decreased by 0.7 in the 6 months before the start of ETF (P<0.05) and increased by 1.4 in the 6 months thereafter (P<0.05). In men, BMI changes were similar (-0.8 and +1.1), but not statistically significant. Forced expiratory volume in 1 second as percent of predicted significantly decreased in time from a median of 28% to 26% at the start of ETF to 25% after 6 months (P=0.0013), with similar trends in women and men. There was no correlation between changes in weight and lung function. CF-related diabetes was already present in 12 patients and developed in 1 more patient after the start of ETF.

Conclusions: ETF improved body weight and BMI but not pulmonary function in 26 patients with end-stage CF. Clinical outcomes were similar in women and men, but the sample size of men was too small to determine statistical significance.