Polyautoimmunity in patients with Rheumatoid Arthritis
Author
Hagelskjær, Amalie Made
Term
5. Term (Master thesis)
Education
Publication year
2021
Pages
18
Abstract
Rheumatoid arthritis (RA) is an autoimmune joint disease. Some people have RA-related antibodies in their blood (seropositive), while others do not (seronegative). This study examined how common it is to have at least one other autoimmune disease besides RA (polyautoimmunity) at the time of RA diagnosis, and how often a new autoimmune disease appears in the first five years, comparing seropositive and seronegative patients. Using nationwide Danish health registers (including DANBIO and the Danish National Patient Registry), we identified 12,517 people newly diagnosed with RA. We recorded whether they already had another autoimmune disease at diagnosis and followed them for five years for new diagnoses, using statistical models that also accounted for deaths during follow-up. At diagnosis, seropositive patients were slightly less likely than seronegative patients to have another autoimmune disease (odds ratio 0.88; 95% confidence interval 0.77–1.02). Over the next five years, the same pattern was seen for new autoimmune diagnoses (hazard ratio 0.83; 95% CI 0.62–1.11). Seropositive patients were younger on average (59.4 vs 63.0 years), more often women (68.6% vs 63.0%), and had a higher death rate during follow-up (5.2% vs 3.9%). Overall, the findings suggest that seronegative RA is associated with a higher tendency toward polyautoimmunity at diagnosis and during the first five years, independent of sex, age, treatment, and disease activity, though the differences were modest and uncertain.
Leddegigt (reumatoid artrit, RA) er en autoimmun gigtsygdom. Nogle har RA-relaterede antistoffer i blodet (seropositive), mens andre ikke har (seronegative). Studien undersøgte, hvor hyppigt det er at have mindst én anden autoimmun sygdom ud over RA (polyautoimmunitet) ved diagnosen, og hvor ofte en ny autoimmun sygdom opstår i de første fem år, sammenlignet mellem seropositive og seronegative patienter. Med landsdækkende danske registre (bl.a. DANBIO og Landspatientregistret) fandt vi 12.517 personer med ny RA-diagnose. Vi registrerede, om de allerede havde en anden autoimmun sygdom ved diagnosen, og fulgte dem i fem år for nye diagnoser, med statistiske modeller der også tog højde for dødsfald under opfølgning. Ved diagnosen havde seropositive patienter en lidt lavere sandsynlighed end seronegative for at have en anden autoimmun sygdom (odds ratio 0,88; 95 % konfidensinterval 0,77–1,02). I de næste fem år sås samme mønster for nye autoimmune diagnoser (hazard ratio 0,83; 95 % KI 0,62–1,11). Seropositive var i gennemsnit yngre (59,4 vs. 63,0 år), oftere kvinder (68,6 % vs. 63,0 %) og havde højere dødelighed under opfølgning (5,2 % vs. 3,9 %). Samlet peger resultaterne på, at seronegativ RA er forbundet med en højere tendens til polyautoimmunitet ved diagnosen og i de første fem år, uafhængigt af køn, alder, behandling og sygdomsaktivitet, om end forskellene var beskedne og usikre.
[This apstract has been rewritten with the help of AI based on the project's original abstract]
Keywords