title: Five-Year Follow-up Study of Monoclonal Gammopathy of Undetermined Significance in a Korean Elderly Urban Cohort.
abstract: OBJECTIVE
  We previously reported the prevalence of monoclonal gammopathy of undetermined significance (MGUS) to be 3.3% among an elderly Korean urban cohort recruited during 2005-2006. Here, we report a 5-year follow-up study of the previously identified MGUS cohort.
  
  
  METHODS
  The 680 participants from the initial cohort were followed-up for a median of 5 years. Sera were collected between 2010 and 2011. Two-step screening was performed with standard serum electrophoresis followed by immunofixation and determination of the serum concentration of monoclonal-protein (M-protein).
  
  
  RESULTS
  Of the 680 participants (21 with MGUS), 348 (51%) agreed to participate in the follow-up study and 10 were found to have MGUS. Among the 21 MGUS patients initially identified, nine were followed-up, six had persistent M-protein, and one patient had progressed to multiple myeloma (progression rate, 1.0%/yr). The M-protein disappeared in the remaining two individuals. Among the 339 participants without MGUS who were followed-up, four developed an M-protein. There was no significant difference in survival with respect to the presence of MGUS (p=0.66).
  
  
  CONCLUSIONS
  The 5-year follow-up data show that the natural clinical course of MGUS in Korea is similar to that in Western countries. MGUS was not associated with an increased risk of death over the 5-year study period.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea ; Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yun-Gyoo
authors.initials: YG
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Soo-Mee
authors.initials: SM
authors.lastname: Bang
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jeong-Ok
authors.initials: JO
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Keun-Wook
authors.initials: KW
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Departments of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jung Han
authors.initials: JH
authors.lastname: Song
authors.affiliation: Departments of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Tae-Hee
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Departments of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Ki Woong
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jong-Seok
authors.initials: JS
authors.lastname: Lee
keywords: Follow-up studies; Monoclonal gammopathy of undetermined significance; Prevalence