Chronic kidney disease stage 5 as the prognostic complement of International Staging System for multiple myeloma

Background: Reversal of renal impairment (RI) in patients with multiple myeloma (MM) has been evaluated using the estimated glomerular filtration rate (eGFR _MDRD) formula developed by the Modification of Diet in Renal Disease study group. However, the prognostic impact of eGFR _MDRD at diagnosis of MM is not well studied, particularly its use in conjunction with the International Staging System (ISS). Methods: Newly diagnosed patients with MM were enrolled between 1996 and 2007. Data on clinical features, laboratory tests, and overall survival were compared in terms of corresponding eGFR _MDRD. Results: A total of 387 patients with MM (median age, 71yr) were enrolled. At diagnosis, 56% had ISS stage III disease; the median values of serum creatinine (SCr) and eGFR _MDRD were 1.4mg/dL and 38.2mL/min/1.73m ², respectively. Thirty-four percent of patients had SCr of ≥2.0mg/dL, and 81.2% had chronic kidney disease stages 3-5 (CKD 3-5). Higher CKD stages were significantly more common in men, older patients (≥65yr), and those with Durie-Salmon and ISS stage III, light-chain diseases, anemia, thrombocytopenia, hypercalcemia, elevated serum β ₂ microglobulin, or lactate dehydrogenase. In the Cox regression model, CKD 4-5 or CKD 5 alone was independently associated with poor survival. A diagnosis of CKD 5 was shown to be useful in identifying the subgroup of ISS-III patients at high risk - those with a median overall survival of 7.2months. Conclusions: Our study demonstrates the prognostic impact of eGFR _MDRD in patients with MM and CKD 5 as the ISS-independent surrogate predictor of poorest prognosis.