RESEARCH - Perception of improvement in patients with RA varies with disease activity levels at baseline

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Arthritis Rheum. 2009 Feb 26;61(3):313-320.

Perception of improvement in patients with rheumatoid arthritis varies

with disease activity levels at baseline.

Aletaha D, Funovits J, Ward MM, Smolen JS, Kvien TK.

Medical University of Vienna, Vienna, Austria.

OBJECTIVE: To analyze the minimum clinically important improvement

(MCII) of disease activity measures in rheumatoid arthritis (RA) using

patient-derived anchors, and to assess whether criteria for

improvement differ with baseline disease activity.

METHODS: We used data from a Norwegian observational database

comprising 1,050 patients (73% women, 65% rheumatoid factor-positive,

mean duration of RA 7.7 years). At 3 months after initiation of

therapy, patients indicated whether their condition had improved, had

considerably improved, was unchanged, had worsened, or had

considerably worsened. We used receiver operating characteristic curve

analysis to determine the MCII for the Disease Activity Score based on

the assessment of 28 joints (DAS28), the Simplified Disease Activity

Index (SDAI), and the Clinical Disease Activity Index (CDAI), and

analyzed the effects of different levels of baseline disease activity

on the MCII.

RESULTS: On average, patients started with high disease activity and

improved significantly during treatment (American College of

Rheumatology 20%, 50%, and 70% improvement criteria responses were

37%, 17%, and 5%, respectively). The overall mean (95% confidence

interval [95% CI]) thresholds for MCII after 3 months for the DAS28,

SDAI, and CDAI were 1.20 (95% CI 1.18-1.22), 10.95 (95% CI

10.69-11.20), and 10.76 (95% CI 10.49-11.04), respectively, and the

mean (95% CI) thresholds for major responses were 1.82 (95% CI

1.80-1.83), 15.82 (95% CI 15.65-16.00), and 15.00 (95% CI

14.82-15.18), respectively. With increasing disease activity, much

higher changes in disease activity were needed to achieve MCII

according to patient judgment.

CONCLUSION: The perception of improvement of disease activity of

patients with RA is considerably different depending on the disease

activity level at which they start.

PMID: 19248136

http://www.ncbi.nlm.nih.gov/pubmed/19248136

Not an MD