title: Determining the clinical significance of monoclonal gammopathy of undetermined significance: a SEER-Medicare population analysis.
abstract: BACKGROUND
  Clinical guidelines have recommended annual follow-up examinations of most patients with monoclonal gammopathy of undetermined significance (MGUS); however, evidence supporting this practice is lacking. We performed a population-based study to examine the patterns of disease presentation and outcomes of patients with multiple myeloma, Waldenström macroglobulinemia, and lymphoplasmacytic lymphoma (monoclonal gammopathy-associated malignancies) comparing those with or without a previous MGUS follow-up examination.
  
  
  METHODS
  Patients with monoclonal gammopathy-associated malignancy from 1994 through 2007 were identified using the Surveillance, Epidemiology, and End Results-Medicare linked database and divided into 2 cohorts: those with follow-up (MGUS follow-up examination preceding the diagnosis) and those with no follow-up (no such follow-up examination). We compared the outcomes, including the rates of major complications at cancer diagnosis (acute kidney injury, cord compression, dialysis use, fracture, and hypercalcemia) and survival using propensity score adjustment and Cox proportional hazard models. All statistical tests were 2-sided.
  
  
  RESULTS
  Of the 17,457 study patients, 6% had undergone MGUS follow-up. After multivariable modeling, the follow-up group had significantly fewer major complications at diagnosis (odds ratio 0.68; 95% confidence interval [CI], 0.57-0.80) and better disease-specific (median, 38 vs. 29 months, P < .001; hazard ratio [HR] 0.85; 95% CI, 0.76-0.94) and overall (median, 23 vs. 19 months, P < .001; HR 0.87; 95% CI, 0.80-0.95) survival.
  
  
  CONCLUSIONS
  Patients with MGUS follow-up preceding the diagnosis of a monoclonal gammopathy-associated malignancy can experience fewer major complications and have longer survival than those without such follow-up examinations. Future studies replicating our findings in the non-Medicare population and determining the optimal schedule and cost-effectiveness of MGUS follow-up are warranted.
authors.affiliation: Center for Cancer and Blood Disorders, Gundersen Health System, La Crosse, WI. Electronic address: go.ronald@mayo.edu.
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Go
authors.affiliation: Department of Medical Research, Gundersen Medical Foundation, La Crosse, WI.
authors.forename: Jacob D
authors.initials: JD
authors.lastname: Gundrum
authors.affiliation: Department of Medicine, Medical College of Wisconsin, Milwaukee, WI.
authors.forename: Joan M
authors.initials: JM
authors.lastname: Neuner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D015331:Cohort Studies; D015897:Comorbidity; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D009369:Neoplasms / Q000175:diagnosis / Q000209:etiology; D011159:Population Surveillance; D012189:Retrospective Studies; D012307:Risk Factors; D018426:SEER Program; D012959:Socioeconomic Factors; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology
keywords: Complications; Lymphoplasmacytic lymphoma; Multiple myeloma; Outcomes; Waldenström macroglobulinemia