This article is more than 5 years old. Information may no longer be current.
RA incidence stable in Sweden, estimated at 41 per 100,000
Nationwide register-based incidence of rheumatoid arthritis in Sweden was stable across different case definitions, with an overall incidence estimated at 40.6 per 100,000, according to recent study results.
“In a country with universal access to care, [rheumatoid arthritis] displayed demographic and socioeconomic, but no geographic, variations in incidence, and peaks at an older age than most commonly reported,” researcher Julia F. Simard, ScD, assistant professor at Karolinska Institutet in Stockholm, and colleagues wrote.
Julia F. Simard
Researchers identified 8,826 patients with incident rheumatoid arthritis (RA; mean age, 60.4 years; 70% women) from the Swedish National Patient Register. Incident RA was defined as a first-ever inpatient or nonprimary outpatient care visit listing an RA diagnosis from 2006 to 2008, with a second visit listing RA within 1 year. Patients were excluded if they had been prescribed a disease-modifying antirheumatic drug more than 6 months before their first visit.
Overall RA incidence was 40.6 per 100,000 (95% CI, 39.7-41.4), and among women (n=6,150), it was estimated at 55.7 per 100,000 (95% CI, 54.3-57.1). For men (n=2,676), the rate was 25 per 100,000 (95% CI, 24.0-25.9). Age was a factor and peaked for women and men aged 70 to 79 years (102 per 100,000 for women, 67 per 100,000 for men). Researchers said this suggested that onset occurred at an increased age.
In densely populated areas and among highly educated individuals, age- and sex-standardized incidence was lower. Researchers saw no geographic trends. Observed incidence was altered by about 14% when more liberal and strict definitions for RA were used.
“The register-based incidence of RA was stable across three different case definitions and in subgroup analysis,” the researchers concluded. “The antirheumatic treatment penetration was above 90% in all age groups except the oldest. The results … are important as they reflect the nationwide occurrence of phenotypes considered to be, and treated as, RA in clinical practice.”
Disclosure: Researcher Martin Neovius, PhD, has served on advisory boards for Pfizer.