Five-Years' Follow-up Study for Frequency of Monoclonal Gammopathy of Undetermined Significance (MGUS) in a Korean Elderly Urban Cohort

Abstract 5007

We previously reported the prevalence of MGUS in a Korean Elderly Urban Cohort recruited from 2005 to 2006 (First Wave, Park HK Am J Hematol. 2011;86:752–5). Their plasma samples were screened using immunofixation and free light chain (FLC) assays. Age and gender-adjusted prevalence rates of MGUS were estimated as 3. 3% (95% CI=2. 0–4. 6%), and the age-adjusted prevalence of MGUS was 4. 3% in men (95% CI=1. 9–6. 6%) and 2. 6% in women (95% CI=1. 0–4. 2%). And then we followed them and collected their serum between 2010 and 2011(Second Wave). Among 1, 000 participants of First Wave, 497 participated to the Second Wave and 419 agreed with the donation of serum for protein electrophoresis, immunofixation and FLC assays. Causes of nonattendance were death in 200 (40%), refusal in 197 (40%), move to other area in 69 (14%), and impossible contact in 37 (7%). The frequency of MGUS in Second Wave was 3. 10% (95% CI=1. 44–4. 76%) in all, 4. 27% (95% CI=1. 54–6. 99%) in men, and 1. 92% (95% CI=0. 06–3. 79%) in women. Among 35 MGUS patients in First Wave, 11 were followed. Eight of 11 had persistent MGUS and other 2 showed the disappearance of M protein in Second Wave. The last one showed mild anemia with persistent M protein of 1. 4g/dL suggestive of progression to MM, but was not confirmed because of early death just after Second Wave. Additional 4 MGUS newly developed in Second Wave among 408 persons without MGUS at First Wave. The mean amount of M protein in 13 patients with MGUS was 0. 55g/dL (range: 0. 2∼1. 4). Subtypes of M protein were predominantly A and G in 8 and 5 patients. Light chain was lambda, kappa and none in 8, 4, and 1 patient. Abnormal ratio of FLC was correlated with the presence of MGUS (p=0. 000). In conclusions, the frequency of MGUS is persistently lower in elderly Koreans (3. 1%) than other races.