{
  "abstract": "Objective Rubella and parvovirus B19 (B19V) infections can present with arthritis-like symptoms in adults instead of typical dermatological symptoms. We quantify associations between rubella and B19V, respectively, with arthritis-like complications using real-world diagnostic testing.Design Cross-sectional and retrospective cohort study.Setting Reference laboratories across the USA.Participants Participants with IgM tests for rubella (N=211 917) or B19V (N=644 473) performed at Labcorp from 2014 to 2023. Among these participants, participants with IgM tests for rubella (N=1867) or B19V (N=22 683) and longitudinal laboratory testing through Labcorp were followed for diagnostic tests for rheumatoid arthritis (RA) up to 1.5 years after the viral IgM tests.Primary and secondary outcome measures Primary outcomes were arthritis-like suspicions by providers and diagnostic testing for RA-associated biomarkers.Results Higher proportions of suspicions of arthritis (1.4%, p<0.001) and same-day RA-associated diagnostic testing (1.3%, p<0.001) and positivity (26.4%, p=0.003) were identified in rubella IgM-positive adults compared with rubella IgM-negative adults. A higher proportion of B19V IgM-positive adults had suspected arthritis (12.6%) compared with B19V IgM-negative adults (8.1%, p<0.001). While a higher proportion of B19V IgM-positive adults (21.3%) received RA-associated diagnostic testing compared with B19V IgM-negative adults (14.3%, p<0.001), a lower proportion of B19V IgM-positive adults with RA-associated diagnostic testing (12.8%) tested positive (B19V IgM-negative: 15.5%, p<0.001). There was a 33% increased risk of a suspected RA diagnosis in B19V IgM-positive participants compared with B19V IgM-negative participants (HR=1.33, 95% CI 1.10 to 1.61).Conclusions Increased awareness of non-typical RA symptoms may facilitate differential diagnosis between rubella, B19V and RA. Recent B19V infections do not occur concurrently with RA; recent B19V infections should be considered in the differential diagnosis for RA when patients present with polyarticular joint symptoms.",
  "authors": [
    {
      "affiliations": [
        "Labcorp, Burlington, North Carolina, USA"
      ],
      "name": "Min Kyung Lee"
    },
    {
      "affiliations": [
        "Labcorp, Burlington, North Carolina, USA"
      ],
      "name": "David Alfego"
    },
    {
      "affiliations": [
        "Labcorp, Burlington, North Carolina, USA"
      ],
      "name": "Stanley J Naides"
    }
  ],
  "title": "Association of rubella and parvovirus B19 IgM positivity and suspected rheumatoid arthritis: a retrospective analysis from a large US national reference laboratory (2014–2023)",
  "uid": "97a2ee05-509b-54b2-b1b4-cca8ad1ff844"
}