Comparative Prognostic Performance of Nutritional and Inflammatory Indices in Diffuse Large B-Cell Lymphoma

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma. Despite advances in immunochemotherapy, approximately 30–40% of patients experience relapsed or refractory disease. Nutritional and inflammatory status, reflected by composite indices, may independently influence clinical outcomes. However, the prognostic value of the Prognostic Nutritional Index (PNI), Geriatric Nutritional Risk Index (GNRI), and Hemoglobin-Albumin-Lymphocyte-Platelet (HALP) score has not been well established in DLBCL patients treated with rituximab-based regimens. Methods: We retrospectively analyzed 192 patients with newly diagnosed DLBCL who received at least three cycles of R-CHOP or R-EPOCH at Başakşehir Çam and Sakura City Hospital between January 2020 and January 2026. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal cutoff values. Kaplan–Meier analysis with log-rank testing and univariable/multivariable Cox proportional hazards regression analyses were used to evaluate the prognostic impact of the PNI, GNRI, and HALP on overall survival (OS) and progression-free survival (PFS). Results: Among the six indices evaluated (PNI, GNRI, HALP, SII, ALI, and CAR), the PNI demonstrated the highest discriminatory ability for OS (AUC = 0.734, p = 0.001), followed by the HALP (AUC = 0.671, p = 0.020) and GNRI (AUC = 0.668, p = 0.022). The optimal cutoff values were ≤46.45 for the PNI, ≤46.91 for the GNRI, and ≤223.95 for HALP. Low values of all three indices were significantly associated with elevated LDH levels, advanced Ann Arbor stage, and higher IPI category. Kaplan–Meier analysis demonstrated significantly inferior OS in the low PNI (52.8 ± 2.6 vs. 67.1 ± 1.2 months, p = 0.001), low GNRI (49.5 ± 3.1 vs. 66.0 ± 1.4 months, p = 0.001), and low HALP (58.8 ± 2.8 vs. 64.9 ± 1.2 months, p = 0.005) groups. In separate multivariable Cox models adjusted for sex and IPI, the PNI (HR = 0.216, p = 0.009), HALP (HR = 0.276, p = 0.031), and GNRI (HR = 0.294, p = 0.011) remained independently associated with OS. No significant association was observed between these indices and PFS. Conclusions: The PNI, GNRI, and HALP are independent prognostic markers in patients with DLBCL treated with rituximab-based regimens. These readily available and inexpensive baseline indices may complement the IPI in identifying patients at higher risk of adverse outcomes and support risk stratification at diagnosis.