Badprognosis is multiple myeloma is indicated by -

The most common cause of kidney failure in multiple myeloma is due to proteins secreted by the malignant cells. Myeloma cells produce monoclonal proteins of varying types, most commonly immunoglobulins (antibodies) and free light chains, resulting in abnormally high levels of these proteins in the blood. Depending on the size of these proteins, they may be excreted through the kidneys. Kidneys can be damaged by the effects of proteins or light chains. Increased bone resorption leads to hypercalcemia and causes nephrocalcinosis, thereby contributing to the kidney failure. Amyloidosis is a distant third in the causation. People with amyloidosis have high levels of amyloid protein that can be excreted through the kidneys and cause damage to the kidneys and other organs. Light chains produce myriad effects that can manifest as the Fanconi syndrome (type II kidney tubular acidosis). Impaired kidney function may develop, either acutely or chronically, and with any degree of severity. Poor prognostic factors include the following: Tumor mass Hypercalcemia Bence Jones proteinemia Renal impairment, azotemia (ie, stage B disease or creatinine level >2 mg/dL at diagnosis) Ref Davidson 23rd edition pg 786