Patients with chronic lymphocytic leukemia (CLL) who have a body mass index (BMI) of 40 or higher (obesity class 3) are at a greater risk of infection than patients with a normal BMI, according to a real-world study.
The findings were presented at the Thirteenth Annual Meeting of the Society of Hematologic Oncology (SOHO 2025).
The goal of the analysis was to understand the impact of obesity on infection risk in CLL patients treated with BTK inhibitors. The authors wrote that “while some studies suggest obesity can confer survival benefits in various diseases, the effect of obesity on infection risk in CLL patients treated with BTKi is unclear.”
To determine the five-year infection risk in patients with CLL who received a BTKi therapy and had been diagnosed with obesity, the researchers analyzed real-world data from the TriNetX Global Collaborative Network. A total 7,372 CLL patients treated with BTKi were analyzed across BMI groups overweight and obesity classes 1–3 and then compared with matched normal-BMI patients.
The study found that CLL patients with class 3 obesity (BMI ≥40) had the highest infection risk among all BMI groups treated with BTK inhibitors. These patients had a 39.3% infection rate over five years, compared with 30.9% in normal-weight patients. Class 3 obesity was also associated with significantly lower five-year infection-free survival (38.98% vs 51.31%). Infection risk decreased with lower obesity classes and was not significantly elevated in overweight patients. Second-generation BTK inhibitors were associated with a modest reduction in infection risk compared with ibrutinib, but the risk remained higher than in patients with normal BMI.
“Class III obesity significantly increases infection risk and lowers infection-free survival in BTKi-treated CLL patients, highlighting the need to consider BMI in treatment risk assessment,” the authors wrote.
Reference
Obesity heightens infection risk in CLL patients treated with BTK inhibitors. Abstract #CLL-1219. Presented at the Society of Hematologic Oncology 2025 Annual Meeting; September 3-6, 2025; Houston, Texas.
