Diabetes mellitus predicts inferior survival in diffuse large B-cell lymphoma: a propensity score-matched analysis

Purpose: Diabetes mellitus (DM) is associated with elevated cancer risk and poor survival. The objective of this study was to assess the prognostic value of DM in diffuse large B-cell lymphoma (DLBCL). Methods: Five hundred and fifty-three newly diagnosed DLBCL patients whose treatments included rituximab were recruited. Propensity score-matched method was performed to balance baseline characteristics and eliminate possible bias. Multivariate Cox regression analyses screened the prognostic risk factors in relation to progression-free survival (PFS) and cancer-specific survival (CSS). Receiver-operator characteristic curves and the corresponding areas under the curve (AUC) assessed the predictive accuracy of international prognostic index (IPI) together with DM. Results: One hundred and nine patients (19.71%) had pre-existing DM. In the propensity-matched cohort, DM was associated with unfavorable PFS and CSS in rituximab era, and it was an independent risk factor for both inferior PFS and CSS, especially in patients with age ≤60 years, IPI 0-2, B symptoms and lactate dehydrogenase ≤upper limit of normal. Prediabetics also demonstrated inferior prognostic outcomes compared to patients with no diabetic tendency. DM as one additional point to IPI had larger AUC compared with IPI alone in CSS prediction and could improve the prognostic capacity of IPI. Conclusion: The results indicate that preexisting DM is an important risk factor for survival. It could help predict life expectancy and build refined prognostication models for DLBCL.