Genotypes and phenotypes: should genetic markers and clinical predictors drive initial treatment decisions in rheumatic diseases?

Cigarette smoking and radiographic progression in rheumatoid arthritis

BACKGROUND

Smoking is a well-established environmental risk factor for the development of rheumatoid arthritis (RA). However, it remains unclear whether smoking influences RA disease progression and whether smokers have more radiographic damage progression than non-smokers over time.

OBJECTIVE

To compare the rates of radiographic damage progression in current smokers and non-smokers in a large prospective RA cohort.

METHODS

The SCQM-RA is a population-based registry monitoring disease activity, radiographic damage and symptoms at regular intervals. All patients in the SCQM-RA database with sequential plain radiographs were included. Joint erosions were assessed in 38 hand and foot joints with a validated scoring method. The rate of erosion progression was analysed using multivariate longitudinal regression models and adjusted for potential confounders.

RESULTS

2004 RA patients with a mean of 3.6 sequential radiographs and 3.1 years of follow-up were included. The 545 (27%) current smokers smoked on average 16 cigarettes per day and had a mean past smoking exposure of 20.6 pack-years. Radiographic joint damage progressed at a similar rate in current smokers and non-smokers (p = 0.26). However, smoking intensity was associated with a significant inverse dose-response; heavy smokers (>1 pack-day) progressed significantly less than non-smokers or moderate smokers (p<0.001).

CONCLUSION

Radiographic joint damage progressed at an equivalent rate in smokers and non-smokers. Furthermore, a significant trend was observed for reduced radiographic progression and generally more favourable functional scores among heavy smokers, suggesting that cigarette smoke does not accelerate RA disease progression.

Pharmacogenomics in the treatment of rheumatoid arthritis: clinical implication and perspective

Rheumatoid arthritis (RA) is a chronic inflammatory disease. The inflammatory process of the joint destroys articular architecture and causes a significant disability. The efficacy of disease modifying antirheumatic drugs such as methotrexate, sulfasalazine and biological response modifiers, is widely accepted. However, the outcome of the treatment with these agents is known to vary among patients. The application of the pharmacogenomics is expected to reduce toxicities and enhance the desirable effects of therapeutic agents for RA. Recently, pharmacogenomic studies on methotrexate, sulfasalazine and tumor necrosis factor-α inhibitors have been reported. These investigations suggest that the pharmacogenomic approach is useful for the treatment of RA, although there are points to be considered before the translation of the pharmacogenomic data into clinical practice. This review focuses on the latest information on the pharmacogenomics of antirheumatic drugs and its clinical implication in the treatment of RA.