Background: Hemoglobin (Hgb) concentration at diagnosis is associated with outcome in cancer. In a recently reported simplified 3-factor prognostic score in Hodgkin lymphoma, Hgb, along with age and clinical stage, outperformed the classical International Prognostic Score with seven parameters.
Methods: In the present study, we investigated if pretherapeutic Hgb concentration added prognostic information to the NCCN-IPI in diffuse large B-cell lymphoma. We included patients from the Danish Lymphoma Registry (LYFO; N = 3499) and from the Molecular Epidemiology Resource (MER; N = 1225), Mayo Clinic and University of Iowa. Four sex-specific Hgb groups were defined: below transfusion threshold, from transfusion threshold to below lower limit of normal, from lower limit of normal to the population mean, and above the mean. We used multivariable Cox regression to estimate the hazard rate ratios (HR) and 95% CIs for overall survival (OS) and event-free survival (EFS), adjusting for sex, NCCN-IPI, comorbidity, and rituximab treatment.
Results: Approximately half of the patients had Hgb levels below the lower limit of normal. Compared to patients with Hgb levels above the mean, an inferior OS was directly correlated with lower pretreatment Hgb within the predefined groups (HR=1.23, HR=1.51, and HR=2.05, respectively). These findings were validated in the MER.
Conclusion: Based on multivariable analysis, lower pretreatment Hgb, even within the normal range but below the mean, added prognostic information to established indices such as the NCCN-IPI and the Charlson comorbidity index.