To investigate the influence of smoking on disease activity, drug need and radiographic joint damage in RF-positive and -negative patients with early RA.
Baseline and 3-yr follow-up data of 896 patients of an early RA cohort comprised clinical and radiographic parameters (Ratingen Score). Information about disease severity, treatment and smoking were obtained by questionnaires. Univariate and multivariate analyses were used to show the influence of smoking on drug use, ACR improvement and joint damage. Smokers and non-smokers were compared according to RF serology.
Fifty per cent of the patients were never, 23% past and 27% current smokers. Current smokers were significantly more often RF-positive (71%) than past (66%) or never smokers (53%), but neither the RF-positive nor the RF-negative current smokers had higher 28-joint disease activity score (DAS28) or radiographic scores than never or past smokers. Within 3 yrs, current smokers had taken significantly more DMARD combinations or biologics. Non-smokers and those with <20 pack-years (PYs) had a 2-fold higher probability to reach ACR improvement than heavy smokers (>20 PYs). However, smokers did not differ in radiographic joint damage when compared with non-smokers of the same serological group.
The higher use of DMARDs may indicate that smoking weakens the potency of anti-rheumatic drugs and/or is needed to control an otherwise higher disease activity. Since the risk of adverse events increases with the amount of drugs taken, this is another reason to persuade RA patients to quit smoking.