The Association Between Low T3 Syndrome and Survival in Patients With Newly Diagnosed Multiple Myeloma: A Retrospective Study

Objective: The correlation between low triiodothyronine (T3) syndrome and shorter survival in malignant tumor patients has been increasingly reported. The objective of the present study was to investigate the association between low T3 syndrome and survival in multiple myeloma (MM) patients. Methods: A total of 201 newly diagnosed MM patients were included in this retrospective study. All participants were divided into 2 groups based on serum free T3 (FT3) level: low T3 syndrome group (FT3 < 2.3 pg/mL) and non-low T3 syndrome group (FT3 ≥ 2.3 pg/mL). Baseline clinical characteristics, overall survival (OS) and progression free survival (PFS) were analyzed. Results: 80 (39.8%) patients had low T3 syndrome. Patients with low T3 syndrome had significantly lower blood hemoglobin and albumin, higher creatinine and β2-microglobulin (β2-MG), higher neutrophil/lymphocyte and (neutrophil + monocyte)/lymphocyte ratio, and more advanced ISS and R-ISS stages (all P < .05). Serum FT3 level was positively associated with blood hemoglobin and albumin, and negatively correlated with β2-MG, creatinine, neutrophil/lymphocyte ratio, and (neutrophil + monocyte)/lymphocyte ratio (all P < .05). Patients with low T3 syndrome had significantly inferior OS time and PFS time (both P < .001). In multivariate Cox analysis, low T3 syndrome was found to be an independent factor associated with OS (P < .001) and PFS (P = .002). Receiver operator characteristic curve analyses showed that FT3 was a predictive marker for death during the entire follow-up period (the area under the curve [AUC] = 0.720, P < .001) and during 1 year (AUC = 0.747, P < .001). Conclusion: Low T3 syndrome might be useful for predicting survival in patients with newly diagnosed MM.