Multiple Myeloma: a Nephrology Department Experience

Introduction: Multiple myeloma (MM) is defined as a malignant proliferation of a single clone of plasma cells typically accompanied by the secretion of monoclonal immunoglobulins that are detectable in the serum or urine. Renal impairment is present in 50% of patients at diagnosis. The aim of this study is to clarify the clinical, biological and prognosis parameters in patients with renal impairment associate to MM and focus on the economic impacts. Material and Methods: This is a retrospective study of MM with renal impairment cases admitted at the nephrology department of the FEZ university hospital in a period extended from January 2010 to December 2011. The diagnosis is based on Southwest Oncology Group criteria (SWOG) and CRAB activity criteria. The outcome is evaluated according to the criteria of the International Myeloma Workings Group. Results:32 myeloma patients were enrolled for a total of 1250 admissions during a period of two years with 15 women and 17 men. The mean age is 59 ± 10 years. 81 % had impaired general condition and bone pain. 88% of cases had anemia including 1 patient with neutropenia, the acute kidney injury was found in 71% of cases, the need for dialysis was required in 25% of patients. The monoclonal peak is observed in all patients who presented in immunofixation: Ig G 57% of cases and Ig A in 28% of cases. Monoclonal plasma cell infiltration>30% occurs in 50% of cases. The cast nephropathy myeloma is sustained in 53%% of cases. The kidney biopsy is performed in 6 patients and concluded for a myeloma tubulopathy in 2 patients and amylosis in 2 patients. All patients enrolled in our series applied for diagnosis criteria according to criteria established by SWOG in all patients. 80% of patients had bulky disease at both classifications SALMON & DURIE and ISS. 94% of our patients were treated by hydration and alkalization, only 19 % received calcitonin and 53% received biphosphonates for severe hypercalcemia. 50 % of patients were proposed for ALEXANIAN Protocol while 25% were proposed to the VAD (Vincristine-Adriamicyne-Dexametasone) protocol. Renal impairment evolution is dominated by normalization of renal function in 39% of patients. The main complication in our series is infection; it occurs in 53% of cases. Mortality occurs in 44%. The main reasons of death are neurologic complications. In univariate analyisis, the risk factors of occurring death are: age> 60years, ISS stage III. 92.22% of hospitalization cost is provided by the hospital with a mean hospitalization days of 34.5 day/patient for a total of 1105 days. Conclusion: Renal involvement in the MM is common and multifactorial. The realization of kidney biopsy is not always necessary for diagnosis. Prognosis is poor due to high tumor mass (22.7% of deaths). Therapies have been directed to slow the disease progression and to prevent complications.