RESEARCH - Is the disease course of RA becoming milder? Time trends since 1985 in an inception cohort of early RA

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Arthritis Rheum. 2005 Sep;52(9):2616-24.

Is the disease course of rheumatoid arthritis becoming milder? Time

trends since 1985 in an inception cohort of early rheumatoid

arthritis.

Welsing PM, Fransen J, van Riel PL.

Department of Rheumatology, Radboud University Nijmegen Medical

Centre, Nijmegen, The Netherlands.

OBJECTIVE: Based on comparisons of short-term cohort studies or

cross-sectional samples of patients from different calendar times, it

has been suggested that present patients with rheumatoid arthritis

(RA) have a milder disease course compared with that of patients in

past decades. This study was undertaken to investigate whether the

course of disease activity and functional disability in patients with

RA has become milder over the past several years. METHODS: We used the

Nijmegen inception cohort of early RA, which included all patients

with newly diagnosed RA who had attended the department of

rheumatology at Radboud University Nijmegen Medical Centre since 1985.

Patients were assessed for disease activity by the Disease Activity

Score in 28 joints (DAS28) every 3 months and for functional

disability by the Health Assessment Questionnaire (HAQ) disability

index (DI) every 6 months. Within the total cohort, 4 subcohorts were

defined, based on the date of inclusion of the patients (1985-1990,

1990-1995, 1995-2000, 2000-2005). To investigate whether the course of

disease activity and functional disability (over time) was different

between the subcohorts, longitudinal regression analysis (linear mixed

models) was used, with the DAS28 and HAQ DI over time as outcome

variables, respectively, and subcohort as the independent variable,

correcting for baseline demographic and clinical characteristics. The

treatment strategy was compared between the subcohorts. RESULTS: The

DAS28 at baseline and over the first 5 years of disease was lower in

the more recent subcohorts. The HAQ DI did not show improvement but

instead a trend toward worsening functional disability. Using

longitudinal regression it was shown that disease activity improved

early in the disease course and stabilized thereafter, and that this

improvement was greater in patients in the more recent subcohorts and

in patients with a higher baseline DAS28. Initially, the HAQ DI also

improved but stabilized thereafter, and this initial improvement was

less pronounced in patients in the more recent subcohorts and was

greater for patients with a higher baseline HAQ DI. The treatment

strategy was more aggressive in the more recent subcohorts, as shown

by a shorter duration from diagnosis to the start of treatment with

prednisone or disease-modifying antirheumatic drugs (DMARDs), and a

greater prevalence of DMARD therapy.

CONCLUSION: The course of disease activity in RA patients has become

milder in more recent years. The reason for this improving trend

remains to be elucidated, although the trend coincides with a more

aggressive treatment strategy.

PMID: 16142762

http://www.ncbi.nlm.nih.gov/pubmed/16142762

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