A Single-Center Retrospective Study to Investigate the Follow-Up of Patients with Monoclonal Proteinemia by Community Physicians in the UK

BACKGROUND: We determined the detection rate of monoclonal gammopathy of undetermined significance (MGUS) and follow-up of MGUS patients in a center that uses reflex testing at globulin levels outside the reference range as part of its routine service to detect monoclonal protein (M-protein). We recorded the natural history and follow-up of these patients. This is one of the first reports on the diagnosis and follow-up of MGUS patients within the UK. PATIENTS AND METHODS: A total of 163 patients diagnosed in 2006 and 393 patients with M-protein on long-term follow-up in 2006 were followed over a period of 10 years (y) by community physicians with laboratory support. RESULTS: In 2006, newly diagnosed patients with an M-protein and total number of patients as a percentage of the Worcestershire population were, respectively, 0.025%, 0.045% (at 45–49y); 0.1%, 0.25% (at 60–64y); and 0.26%, 1.12% (at 75–79y). Patients with M-protein had a survival of 35.5% at 10 y and 43.5% at >10y follow-up. Kaplan–Meier analysis of patients with an M-protein showed that lymphoplasma-cell proliferative disorders (LPD)-free survival was 91% for both 10y and >10y follow-up. LPD-free survival decreased to approximately 73% when competing causes (death due to unrelated causes, transient M-protein, loss to follow-up) were censored. Progression to LPD occurred at initial M-protein values of 3g/L at diagnosis. During follow-up, 38.3% died without evidence of LPD, 12% were diagnosed with transient M-protein, 8.7% developed LPD, 10.9% had stable M-protein, 4.9% showed increasing M-protein, and 25.2% were lost to follow-up. Survival curves showed that M-protein isotype contributed to LPD-free survival in the order IgG=IgM>IgA>biclonal M-protein. CONCLUSION: Geographical variations in the diagnosis and follow-up of MGUS patients in the UK need investigation. From public health viewpoint, it is essential to determine MGUS follow-up to improve clinical care and individualise risk-based follow-up of patients.