Oliguria as an early indicator of mortality risk in patients with multiple myeloma and renal impairment

BACKGROUND: A change in urine output has been recently recognized as a valuable biomarker of acute kidney injury that is associated with mortality in critically ill patients. We investigated the prognostic impact of oliguria for survival outcomes in multiple myeloma (MM) patients presenting with renal impairment (RI). METHODS: Retrospective data on 98 patients with MM and RI, who received initial treatment with novel therapies, were analyzed. Oliguria was defined as a urine output of <0.5 mL/kg/h. RESULTS: The baseline median eGFR was 39.7 mL/min (range, 5.1-59.8). Achievement of renal complete response (CR) was observed in 39.8% of patients. Nine patients (9.2%) presented with oliguria at initial diagnosis, and 4 initially required dialysis. Over a median follow-up period of 17.1 months (range, 1.7-100.0), the median overall survival (OS) was 38.7 months (95% CI 25.0-52.5). Multivariate analyses indicated that oliguria at diagnosis [hazard ratio (HR) 3.628, 95% CI 1.366-9.849, P=0.011], and thrombocytopenia <100×10(9)/L at diagnosis (HR 2.534, 95% CI 1.068-6.015, P=0.035), were significantly associated with overall survival. CONCLUSION: Oliguria was significantly associated with higher mortality in MM patients with RI. Therefore, close monitoring of urine output could be important for these patients.