Prevalence and mortality of chronic kidney disease in lymphoma patients: A large retrospective cohort study

In patients with lymphoma, an important issue that has been recognized is renal involvement, including glomerulonephritis, acute kidney injury, and lymphoma infiltrating the kidney. However, the prevalence and mortality of chronic kidney disease (CKD) have not been fully understood in lymphoma patients. This study aimed to evaluate the prevalence of CKD and its impact on mortality in those patients.This was a retrospective cohort study of 429 consecutive lymphoma patients who were admitted or regularly visited our hospital from January 2013 to October 2016. CKD was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m and/or proteinuria ≥ 1+ that was sustained for at least 3 months. The prevalence of CKD at enrollment was evaluated according to the modified CKD classification by Kidney Disease: Improving Global Outcomes (KDIGO) (eGFR and proteinuria category). Dipstick proteinuria was classified into 3 grades: A1 for - and ±; A2 for 1+ or 2+; and A3 for ≥3+. The eGFR (mL/min/1.73 m) was classified into 6 stages: G1 for ≥90, G2 for 60 to 89, G3a for 45 to 59, G3b for 30 to 44, G4 for 15 to 29, and G5 for <15. The cumulative mortality rate was estimated using the Kaplan-Meier method, with stratification into 2 groups based on the presence or absence of CKD. Furthermore, a multivariate Cox proportional hazards regression model was used to calculate the hazard ratio (HR) and its 95% confidence interval (CI) for all-cause mortality, after adjustments for age, sex, pathologic type, clinical stage of lymphoma, presence or absence of diabetes mellitus, hypertension, and cardiovascular disease.The mean follow-up period was 3.06 ± 0.96 years, and the prevalence of CKD at study enrollment was 34.5%. The cumulative mortality rate was 20.7%, and was significantly higher in the CKD group than in the group without CKD (36.4% vs 18.0%, P = .02). Multivariate analysis found mortality to be significantly associated with CKD (HR 1.58; 95% CI, 1.01-2.46), and this association was the most robust with very high-risk CKD (HR 6.94; 95% CI, 2.50-17.33).The prevalence of CKD in lymphoma patients was high. CKD should be considered an independent risk factor for mortality among patients with lymphoma.