B₂-Microglobulin (β₂M) in Renal Disfunction Patients. Effect in Overall Survival in ISS-Subgroups in Newly Diagnosed Multiple Myeloma (NDMM) Patients

β₂-microglobulin (β₂M) is included in the prognostic International Scoring System to stablish prognostic groups in NDMM patients. The first clinical application of β₂M was the monitoring of processes with renal dysfunction. Elderly patients have more incidence of renal disfunction due to common comorbidities like Diabetes Mellitus or arterial Hypertension.