NCCN-IPI score-independent prognostic potential of pretreatment uric acid levels for clinical outcome of diffuse large B-cell lymphoma patients.

Background: Blood-based parameters are gaining increasing interest as potential prognostic biomarkers in patients with diffuse large B-cell lymphoma (DLBCL). The aim of this study was to comprehensively evaluate the prognostic significance of pretreatment plasma uric acid levels in patients with newly diagnosed DLBCL.

Methods: The clinical course of 539 DLBCL patients, diagnosed and treated between 2004 and 2013 at two Austrian high-volume centres with rituximab-based immunochemotherapy was evaluated retrospectively. The prognostic influence of uric acid on overall survival (OS) and progression-free survival (PFS) were studied including multi-state modelling, and analysis of conditional survival.

Results: Five-year OS and PFS were 50.4% (95% CI: 39.2-60.6) and 44.0% (33.4-54.0) in patients with uric acid levels above the 75th percentile of the uric acid distribution (Q3, cut-off: 6.8 mg dl), and 66.2% (60.4-71.5) and 59.6% (53.7-65.0%) in patients with lower levels (log-rank P=0.002 and P=0.0045, respectively). In univariable time-to-event analysis, elevated uric acid levels were associated with a worse PFS (hazard ratio (HR) per 1 log increase in uric acid 1.47, 95% CI: 1.10-1.97, P=0.009) and a worse OS (HR=1.60, 95% CI: 1.16-2.19, P=0.004). These associations prevailed upon multivariable adjustment for the NCCN-IPI score. Uric acid levels significantly improved the predictive performance of the R-IPI and NCCN-IPI scores, and in multi-state analysis, it emerged as a highly significant predictor of an increased risk of death without developing recurrence (transition-HR=4.47, 95% CI: 2.17-9.23, P<0.0001).

Conclusions: We demonstrate that elevated uric acid levels predict poor long-term outcomes in DLBCL patients beyond the NCCN-IPI risk index.