Reduced disability at five years with early treatment of inflammatory polyarthritis: results from a large observational cohort, using propensity models to adjust for disease severity

Arthritis Rheum. 2001 May;44(5):1033-42. doi: 10.1002/1529-0131(200105)44:5<1033::AID-ANR182>3.0.CO;2-G.


Objective: To determine the effect of treatment with disease-modifying antirheumatic drugs (DMARDs) and/or steroids on 5-year disability outcome in patients with inflammatory polyarthritis.

Methods: Three hundred eighty-four patients registered by the Norfolk Arthritis Register (a primary care-based observational cohort) were followed up for 5 years. Treatment details and Health Assessment Questionnaire (HAQ) scores were recorded annually. Logistic regression was used to model differences in baseline factors associated with the start of DMARDs and/or steroids within 12 months of baseline. Based on this model, each subject was given a probability of starting treatment ("propensity score"). A second model compared the odds of disability (HAQ score > or =1.00) in treated and untreated patients, adjusting for differences in disease severity using the propensity score.

Results: Unadjusted analysis suggested that patients who received treatment had an increased odds of a worse outcome compared with those who did not receive treatment. When adjusted for differences in disease severity, using the propensity score, early treatment (within 6 months of symptom onset) was associated with a similar odds of disability at 5 years compared with those not treated (odds ratio 0.71; 95% confidence interval 0.34, 1.44). In contrast, starting treatment later (> or =6 months) was associated with a 2-fold increased odds of having a HAQ score > or =1.00 at 5 years.

Conclusion: The propensity score was a useful method of adjusting for "confounding by indication" in observational studies. Furthermore, this study showed that early treatment with DMARDs/steroids (within 6 months of symptom onset) reduced the odds of disability 5 years later to a level comparable with that of patients judged clinically as not requiring treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antirheumatic Agents / therapeutic use*
  • Arthritis / drug therapy*
  • Arthritis / immunology
  • Arthritis / rehabilitation*
  • Disability Evaluation
  • Female
  • Health Status Indicators
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Patient Dropouts
  • Phenylketonurias
  • Prospective Studies
  • Registries
  • Treatment Outcome


  • Antirheumatic Agents