Proteinuria is a simple sign of systemic inflammation that leads to a poor prognosis in individuals affected with non-Hodgkin lymphoma

Background: The clinical significance of proteinuria has not been fully understood among patients who are affected with non-Hodgkin lymphoma (NHL). Methods: A 1-year prospective cohort study was conducted to ascertain the association between proteinuria and mortality in 46 hospitalized NHL patients. Proteinuria was defined as persistent dipstick test >= 1+, and the urinary protein creatinine ratio (UPCR), as a quantitative index of protein excretion, was measured simultaneously. A multivariable linear regression model was constructed to determine factors associated with UPCR. Statistical associations between proteinuria and time to mortality were analyzed using the Kaplan-Meier method and multivariable proportional hazards regression analysis, adjusted for covariates including disease severity, renal function, and serum interleukin-6 (IL-6) concentration. Results: The prevalence of proteinuria was 15.2% in the NHL patients. UPCR was significantly associated with the serum IL-6 level (standardized beta = 0.360, p = 0.0440). The cumulative mortality was significantly higher in proteinuric patients than in non-proteinuric patients, with a graded relationship between the severity of UPCR and mortality. The mortality risk increased with increasing UPCR grade: the hazard ratio (95% confidence interval) was 4.90 (1.29 - 32.3) for UPCR 30 - 300 mg/g and 17.8 (2.84 - 150) for UPCR > 300 mg/g, respectively, when UPCR < 30 mg/g was set as the reference. Conclusions: Proteinuria is a simple sign of coexisting systemic inflammation due to NHL and a harbinger of a poor prognosis.