Determination of the kidney injury in multiple myeloma according to the KDIGO 2012 acute kidney injury guideline and relationship between serum β2 microglobulin and free T3 levels and acute kidney injury

Renal failure is common in multiple myeloma (MM) and is one of the main causes of morbidity and mortality. Despite many advances in diagnosis and treatment, almost half of the patients present with renal failure at presentation. In our study, we aimed to examine the relationship between acute kidney injury (AKI) and serum B2 microglobulin (sB2M) levels, and free T3 (fT3) levels, which has been proven to change in patients with renal failure without thyroid disease. The data of MM patients who were newly diagnosed between 2012 and 2015 were retrospectively analyzed. Bone marrow biopsy had been performed in all cases for final diagnosis. Patients were staged according to the International Staging System (ISS). The AKI staging was performed according to the Kidney Disease Improving Global Outcomes guideline. Twenty-six patients (10 females,16 males) diagnosed with MM were included. The mean age of the patients was 69.33±14.372 years. AKI was found in 92% (n=24) of the patients. According to ISS: one patient was classified as stage-I, five as stage-II, and 20 as stage-III. There was no significant difference between the mean sB2M levels and the stages of AKI in MM patients. The mean sB2M levels of the patients who required hemodialysis due to renal failure were higher than those who did not. In addition, lower fT3 levels were associated with AKI and advanced stage of MM. High sB2M levels may be a risk factor for severe AKI and hemodialysis requirement in patients with MM, and low fT3 levels also may be an indicator of AKI in these patients.