RESUMO
Objective: To analyze the clinical presentation and progression risk factors of patients with monoclonal gammopathy of undetermined significance (MGUS) in China. Methods: We retrospectively assessed the clinical features and disease progression of 1 037 patients with monoclonal gammopathy of undetermined significance between January 2004 and January 2022 at Peking Union Medical College Hospital. Results: A total of 1 037 patients were recruited in the study, including 636 males (63.6%) , with a median age of 58 (18-94) years. The median concentration of serum monoclonal protein was 2.7 (0-29.4) g/L. The monoclonal immunoglobulin type was IgG in 380 patients (59.7%) , IgA in 143 patients (22.5%) , IgM in 103 patients (16.2%) , IgD in 4 patients (0.6%) , and light chain in 6 patients (0.9%) . 171 patients (31.9%) had an abnormal serum-free light chain ratio (sFLCr) . According to the Mayo Clinic model for risk of progression, the proportion of patients in the low-risk, medium-low-risk, medium-high risk, and high-risk groups were 254 (59.5%) , 126 (29.5%) , 43 (10.1%) , and 4 (0.9%) , respectively. With a median follow-up of 47 (1-204) months, 34 of 795 patients (4.3%) had disease progression, and 22 (2.8%) died. The overall progression rate was 1.06 (0.99-1.13) /100 person-years. Patients with non-IgM MGUS have a markedly higher disease progression rate per 100 person-years than IgM-MGUS (2.87/100 person-years vs 0.99/100 person-years, P=0.002) . The disease progression rate per 100 person-years in non-IgM-MGUS patients of Mayo classification low-risk, medium-low risk and medium-high risk groups were 0.32 (0.25-0.39) /100 person-years, 1.82 (1.55-2.09) /100 person-years, and2.71 (1.93-3.49) /100 person-years, which had statistically difference (P=0.005) . Conclusion: In comparison to non-IgM-MGUS, IgM-MGUS has a greater risk of disease progression. The Mayo Clinic progression risk model applies to non-IgM-MGUS patients in China.