Patients with early inflammatory polyarthritis diagnosed within the new millennium experienced improved disease activity, compared with those diagnosed during the early 1990s, according to findings published in the Annals of the Rheumatic Diseases.
“The natural history of [inflammatory polyarthritis] and rheumatoid arthritis is becoming less severe; therefore, it is difficult to infer whether any improvements in long-term outcome (ie, 10 years) are associated with less severe disease or with the changes in treatment strategy,” James M. Gwinnutt, PhD, of the University of Manchester, United Kingdom, and colleagues wrote.
To compare outcomes including disease activity, disability and mortality over the course of 10 years among patients with early inflammatory polyarthritis, before and after the new millennium, the researchers recruited 1,653 participants from the Norfolk Arthritis Register, which began collecting primary care data on individuals with inflammatory polyarthritis in the Norfolk, U.K., region in 1990. Among the patients, 1,022 were recruited to the register from 1990 to 1994, while 631 were from 2000 to 2004.
Patients with early inflammatory polyarthritis diagnosed since 2000 experienced improved disease activity, compared with those diagnosed during the early 1990s, according to researchers.
The researchers collected clinical and demographic data on patients in both groups at baseline, as well as at years 1, 2, 3, 5, 7 and 10. In addition, they compared disease activity, defined as swollen or tender 51 joint counts, and disability, as determined by the Health Assessment Questionnaire, between the groups using population-average negative binomial regression and generalized estimating equation analysis. Mortality risk across 10 years was calculated using Cox models, and mortality rate ratios were estimated using Poisson regression, adjusting for changes in the general population.
According to the researchers, patients in the group recruited from 2000 to 2004 had 17% lower swollen-joint disease activity and disability over 10 years (95% CI, –23% to –10%). However, tender-joint disease activity and disability were comparable between the two groups. In addition, patients recruited after the new millennium demonstrated a reduced risk for all-cause (HR = 0.72; 95% CI, 0.56-0.95) and cardiovascular disease mortality (HR = 0.58; 95% CI, 0.37-0.93) compared with their counterparts in the earlier group. However, after adjusting for changes in the general population, the difference in mortality risk between the two groups was not significant.
“The results of the disease activity and disability analyses extend previous literature looking at outcome of patients over 5years,” Gwinnut and colleagues wrote. “However, our analysis is the first study to directly compare the longitudinal clinical outcome over 10 years between two cohorts of patients recruited 10 years apart.” – by Jason Laday
Disclosure: The researchers report no relevant financial disclosures.