Monoclonal Gammopathy of Undetermined Significance and COVID-19: Results from the Population-Based Iceland Screens Treats or Prevents Multiple Myeloma Study (iStopMM)

• Published in: Blood 2021-11, Vol.138 (Supplement 1), p.154-154
• Main Authors: Rögnvaldsson, Sæmundur, Eythorsson, Elias, Thorsteinsdottir, Sigrun, Vidarsson, Brynjar, Onundarson, Pall Torfi, Agnarsson, Bjarni Agnar, Sigurdardottir, Margret, Thorsteinsdottir, Ingunn, Olafsson, Isleifur, Runolfsdottir, Hrafnhildur Linnet, Helgason, Dadi, Emilsdóttir, Arna, Bjornsson, Aron H, Kristjansdottir, Gudrun, Thordardottir, Asdis Rosa, Indridason, Olafur Skuli, Jonsson, Asbjorn, Gislason, Gauti Kjartan, Olafsson, Andri, Steingrimsdottir, Hlif, Kampanis, Petros, Hultcrantz, Malin, Durie, Brian G.M., Harding, Stephen, Landgren, Ola, Love, Thorvardur Jon, Palsson, Runolfur, Kristinsson, Sigurdur Y
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2021-153145

Introduction Multiple myeloma (MM) patients have an increased risk of severe coronavirus disease 2019 (COVID-19) when infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Monoclonal gammopathy of undetermined significance (MGUS) precedes MM and related disorders and affects 4.2% of the general population over the age of 50 years. MM and MGUS are associated with immune dysfunction that is believed to contribute to the development of severe COVID-19. Currently, no systematic data on MGUS and COVID-19 have been published. We conducted a large population-based cohort study to evaluate whether MGUS was associated with SARS-CoV-2 infection and the development of severe COVID-19. Methods Data on all SARS-CoV-2 test results and COVID-19 severity was acquired from the COVID-19 Outpatient Clinic at Landspitali - The National University Hospital of Iceland. The first case of COVID-19 in Iceland was diagnosed on February 28 th, 2020. Since then, the Icelandic authorities have followed an aggressive strategy of SARS-CoV-2 testing and contact tracing. All SARS-CoV-2-positive individuals were immediately contacted and those with active infection were enrolled into telehealth monitoring consisting of repeated standardized interviews conducted by a nurse or physician. If clinical deterioration was detected, patients were assessed in person at the COVID-19 Outpatient Clinic and admitted if needed. Study participants were included from the Iceland Screens Treats or Prevents Multiple Myeloma study (iStopMM). The study is an ongoing population-based screening study for MGUS and randomized trial of follow-up strategies. Out of the 148,708 Icelanders who were born 1976 and earlier and were alive on September 9 th 2016, 80,759 (54%) provided informed consent for study participation and 75,422 (94%) of those provided a blood sample for MGUS screening by serum protein electrophoresis (SPEP) and free light chain (FLC) assay. MGUS was determined by current criteria using SPEP and FLC assay data. Individuals who had died, been diagnosed with MM and related disorders, or were undergoing treatment for smoldering MM prior to February 28 th were excluded. First, the association of MGUS and testing positive for SARS-CoV-2 was evaluated. We used a test negative design and included participants who had been tested at least once for SARS-CoV-2 between February 28 th and December 31 st, 2020. The association of MGUS and a positive test for SARS-CoV-2 was assessed using l