Kidney function in newly diagnosed myeloma patients: factors associated with kidney impairment and recovery

Kidney disease is a common complication of multiple myeloma (MM) and a risk factor for increased morbimortality. In this retrospective cohort study based on medical records, we analyzed the kidney function of patients with renal disease related to MM during the first year of treatment. All patients included were consecutively admitted to the outpatient services of two hospitals between January 2009 and January 2019 and met the diagnostic criteria for MM regardless of the reason for seeking medical help. We excluded patients who had kidney disease or who were on dialysis before MM diagnosis. We investigated the factors associated with renal function recovery using multivariate analysis. We evaluated 167 patients (median age of 66 ± 11.49 years). Almost half of the patients had arterial hypertension (76; 45.5%). The majority had International Staging System (ISS) grades 3 (73; 43.7%) or 2 (60; 35.9%). Seventy-four (44%) patients had an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m² at the time of MM diagnosis. Fifty-two patients (31%) underwent hematopoietic stem cell transplantation (HSCT). After 12 months, 4 (2.3%) patients needed dialysis, and 18 (10.7%) died. The factors associated with an eGFR < 60 ml/min/1.73 m² were anemia, hyperuricemia, 24-hour proteinuria > 1.0 g, and extramedullary plasmacytoma. However, only baseline renal function (eGFR > 60 ml/min/1.73 m²) and HSCT were associated with greater recovery of renal function at 12 months of follow-up.