Chronic kidney disease in patients with cancer and its association with occurrence of venous thromboembolism and mortality

Introduction: The risk for occurrence of venous thromboembolism (VTE) in cancer patients has been the aim of numerous investigations. Chronic kidney disease (CKD) is a frequent comorbidity in cancer patients and has been found to be a risk factor for VTE in the general population. We investigated the association of CKD with VTE and mortality in cancer patients.

Methods: Patients were recruited into the prospective cohort study, Vienna Cancer and Thrombosis Study (CATS). CKD was estimated with equations for glomerular filtration rate (eGFR) based on serum creatinine by Modification of Diet in Renal Disease (MDRD), CKD Epidemiology collaboration (CKD-EPI) and Cockcroft-Gault equation (C-G). Patients were subsequently classified to stages of CKD according to the Kidney Diseases Outcomes Quality Initiative. Primary endpoint was occurrence of VTE and secondary endpoint was death.

Results: The cohort of 1100 patients was prospectively followed over a median of 723 days. CKD with an eGFR of under 90 ml/min was common with a prevalence of 71.1%, 67.0% or 51.5% of patients calculated with MDRD, CKD-EPI and C-G equations, respectively, but severe CKD (eGFR<30 ml/min) was rare. Patients with a moderately decreased eGFR (90-60 ml/min/1.73 m(2)) based on CKD-EPI had a subdistribution hazard ratio of 0.68 (95% confidence interval 0.43-1.06). An association between CKD and occurrence of VTE or mortality could also not be shown with the other equations.

Conclusions: In our investigation of a large cohort of cancer patients with a high prevalence of CKD, a reduced eGFR was not an independent risk factor for occurrence of VTE or death.