Overweight, obesity and significant weight gain in adult patients with cystic fibrosis association with lung function and cardiometabolic risk factors.

For patients with cystic fibrosis (CF), maintaining a normal BMI is associated with better pulmonary function (FEV1) and survival. Given therapy improvements, some patients are now overweight, obese or present rapid weight gain. However, the impact of being overweight on clinical outcomes (e.g. FEV1 & metabolic complications) remains unknown.

Baseline data from 290 adult CF patients and observational follow-up (3.5 years; n = 158) were collected. BMI categories: underweight (UW < 18.5 kg/m²), normal (NW 18.5-26.9 kg/m²), and overweight/obese (OW ≥ 27 kg/m²). Follow-up data (weight change over time): weight loss (WL>10%), stable (WS), and weight gain (WG>10%). BMI categories and follow-up data were compared to FEV1 and cardiometabolic parameters: glucose tolerance, estimated insulin resistance (IR), blood pressure (BP), and lipid profile.

For BMI categories, 35 patients (12.1%) were UW, 235 (81.0%) NW, and 20 (6.9%) OW. Compared to UW and NW patients, OW patients are older (p < 0.001), had less pancreatic insufficiency (p = 0.009), a higher systolic BP (p = 0.004), higher LDL (p < 0.001), and higher IR (p < 0.001). Compared to UW patients, OW patients had a better FEV1 (p < 0.001). For weight change, WL was observed in 7 patients (4.4%), WS in 134 (84.8%) and WG in 17 patients (10.8%). Compared to WL and WS patients, WG patients had a 5% increase in FEV1 accompanied by higher IR (p = 0.017) and triglycerides (p < 0.001). No differences were observed for glucose tolerance for neither BMI nor weight change.

A higher weight or weight gain over time are associated with a better FEV₁ but also some unfavorable cardiometabolic trends.