Severe acute kidney injury and multiple myeloma: Evaluation of kidney and patient prognostic factors

Abstract Background Patients with multiple myeloma (MM) manifesting acute kidney injury (AKI) and who later recover renal function and independence from renal replacement therapy (RRT) are considered to have a better outcome. The aim of this work was to study the factors associated with renal function recovery (independence of hemodialysis) and longer survival in these patients. Methods A retrospective single center study including patients with a diagnosis of MM and severe AKI, defined as stage 3 of the Kidney Disease: Improving Global Outcomes (KDIGO) criteria: 3.0 times baseline increase in serum creatinine (sCr) or increase in sCr to ≥ 4.0 mg/dL or initiation of RRT, was conducted. Data was registry-based and collected between January 2000 and December 2011. We examined demographic and laboratorial data, presenting clinical features, precipitating factors, need for RRT and chemotherapy. Death was considered the primary endpoint. Results Lower serum β2-microglobulin was the only independent factor associated with recovery of renal function and independence of RRT (OR 0.95, 95% CI: 0.91–0.99, P  = 0.02). The median survival after AKI was 10.7 ± 12.1 months. The factors associated with longer survival were independence of RRT (HR 2.21; 95% CI: 1.08–4.49; P  = 0.02), lower CRP (HR 1.07; 95% CI: 1.03–1.12; P  = 0.001) and younger age (HR 1.03; 95% CI: 1.01–1.06; P  = 0.005). Conclusions Our study suggests that MM patients with lower serum β2-microglobulin have a higher likelihood of recovering renal function after severe AKI. Independence of RRT, lower CRP and younger age are associated with longer survival.