Renal failure in multiple myeloma: presenting features and predictors of outcome in 94 patients from a single institution.

BACKGROUND Twenty percent of patients with multiple myeloma (MM) have renal failure. OBJECTIVE To analyze the presenting features, the response to therapy, and the factors associated with renal function recovery and survival in 94 patients with MM and renal failure. PATIENTS AND METHODS Medical records of patients from our institution with MM and renal failure diagnosed between January 1969 and December 1994 were reviewed. The statistical methods consisted of Kaplan-Meier survival curves, the log-rank test, logistic regression analysis, and the Cox proportional hazards model for survival analysis. RESULTS Renal failure was observed in 94 (22.2%) of 423 patients. Patients with renal failure had more advanced disease than the others. Patients with renal failure had a lower response rate to chemotherapy than those with normal renal function (39% vs 56%; P<.001). However, when patients dying within the first 2 months of treatment were excluded, no significant differences in the response rate were found between patients with renal failure and those with normal renal function. Renal function recovery was observed in 26% of patients. Serum creatinine level (<354 micromol/L [<4 mg/dL]), serum calcium level (> or =2.88 mmol/L [> or = 11.5 mg/dL]), and amount of proteinuria (< 1 g/24 h) were associated with renal function recovery. Patients who recovered renal function had a median survival of 28 months vs 4 months for those with nonreversible renal failure (P<.001). In the multivariate analysis, only serum creatinine level (P=.003) and response to chemotherapy (P<.001) were correlated with survival. CONCLUSIONS Renal failure was present in almost one fourth of patients with MM. Patients with reversible renal failure had longer survival than those not recovering renal function. When patients dying within the first 2 months of treatment were excluded, the response rate was not affected by renal function. Factors associated with renal function recovery were degree of renal failure, presence of hypercalcemia, and amount of proteinuria. Response to chemotherapy and severity of renal failure were the only independent factors associated with survival.