Elevated Fasting Glucose in Patients with Lymphoma: A Real-World Observational Study

Background/Objectives: Patients with lymphoma are at increased risk of dysglycemia due to disease-related and treatment-associated metabolic alterations. This study aimed to characterize fasting capillary glucose patterns in patients with lymphoma undergoing routine capillary fasting blood glucose assessment before fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). Materials and Methods: Consecutive patients with lymphoma undergoing clinically indicated FDG PET/CT at the University Hospital Zurich were included. Capillary fasting blood glucose (cFBG) was measured before tracer administration and categorized according to American Diabetes Association fasting glucose thresholds. Additional analyses were performed in patients examined before 11:00 AM and in patients without known diabetes mellitus. Multivariable linear regression was used to identify factors associated with cFBG. Results: The cohort included 210 consecutive patients with lymphoma (median age 64 years, IQR 48–73; 44% female, 92/210; median BMI 24 kg/m2, IQR 22–28). Known diabetes mellitus was present in 12% (25/210). Median cFBG was 104 mg/dL (IQR 95–115; 5.8 mmol/L, IQR 5.3–6.4). Overall, 64% (135/210) had cFBG values above the normal range (≥100 mg/dL; ≥5.6 mmol/L). Among patients examined before 11:00 AM, this proportion was 69% (81/117). After excluding patients with known diabetes mellitus, 60% (111/185) had cFBG values above the normal range, and 7% (13/185) had values ≥126 mg/dL (≥7.0 mmol/L). In multivariable analysis, BMI and regular exercise were independently associated with cFBG. Conclusions: Almost two-thirds of patients with lymphoma undergoing FDG PET/CT had cFBG values above the normal range, including 60% of those without known diabetes mellitus. These findings highlight the need for improved dysglycemia screening and management in lymphoma care.