Early treatment with, and time receiving, first disease-modifying antirheumatic drug predicts long-term function in patients with inflammatory polyarthritis.
OBJECTIVE
To investigate the influence of early disease-modifying antirheumatic drug (DMARD) treatment on long-term functional outcome in patients with recent-onset inflammatory polyarthritis (IP), and the impact of the duration of first and subsequent DMARD treatment.


METHODS
642 subjects from a primary care registry of patients with new-onset IP, recruited 1990-4, were followed up for 10 years. Mean change in Health Assessment Questionnaire (HAQ) scores between baseline and 10 years were compared by time to, and time receiving, first DMARD treatment and total time receiving treatment, using linear regression. Adjustment for time-dependent confounders and censoring was performed using marginal structural weights.


RESULTS
When adjusted for baseline and subsequent disease severity, those treated early (<6 months from symptom onset) experienced a non-significant improvement in function compared with those never treated (adjusted mean difference in change (adj_MDIC) in HAQ -0.24; 95% CI -0.58 to 0.09); and a significant benefit for each additional month of treatment within 6 months of the onset of symptoms (adj_MDIC -0.10; 95% CI -0.19 to -0.02). Patients who discontinued their first DMARD within 6 months experienced a significant deterioration in long-term function (adj_MDIC in HAQ 0.28; 95% CI 0.04 to 0.52), while those who continued their first treatment for > 3 years experienced an improvement (adj_MDIC in HAQ -0.37; 95% CI -0.77 to 0.04).


CONCLUSIONS
The importance of time to, and response to, first DMARD treatment and total duration of DMARD treatment in modifying the 10-year function in patients with IP has been demonstrated.
arc Epidemiology Unit, The University of Manchester, Oxford Road, Manchester, UK.
Tracey M
TM
Farragher
Mark
M
Lunt
Bo
B
Fu
Diane
D
Bunn
Deborah P M
DP
Symmons
D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D001168:Arthritis / Q000188:drug therapy* / Q000503:physiopathology; D015986:Confounding Factors, Epidemiologic; D018450:Disease Progression; D004334:Drug Administration Schedule; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013997:Time Factors; D016896:Treatment Outcome
D018501:Antirheumatic Agents