Cigarette smoking is a risk factor for many diseases, including rheumatoid arthritis (RA). Some previous studies have shown that smoking may also reduce the response to treatment. However, a new study finds that smoking does not affect treatment response in patients receiving combination therapy. The patients studied had early RA for less than 3 years.
Study participants were randomized into four groups. The first two groups received early intensive treatment with methotrexate and etanercept or with methotrexate, hydroxychloroquine, and sulfasalazine (triple therapy). The third and fourth groups received initial treatment with methotrexate alone. Their regimen was intensified by stepping up to methotrexate and etanercept or to triple therapy if the patient still had disease at 24 weeks. The concentration of cotinine, a metabolite of nicotine, in serum specimens drawn at baseline and 48 weeks later, was used to define smokers (>5ng/ml) and heavy smokers (>100 ng/ml). Patients were not asked about passive exposure to cigarette smoke, use of medicinal nicotine, or therapy with isoniazid.
Among 412 participants, 293 were nonsmokers and 119 were smokers, with the majority being heavy smokers. Overall, there was no significant difference in treatment response between smokers and non-smokers at weeks 24, 48, and 102 of therapy. This finding persisted after adjustment for age, sex, race, disease duration, functional status, and other factors.
Smokers and nonsmokers did not differ in the frequency of serious adverse events from treatment. The researchers pointed out, however, that their findings did not eliminate the need to promote smoking cessation in patients with RA. The study was supported in part by AHRQ (HS18517).
See "Serum cotinine as a biomarker of tobacco exposure and the association with treatment response in early rheumatoid arthritis," by Leann B. Maska, M.D., Harlan R. Sayles, M.S., James R. O'Dell, M.D., and others in the December 2012 Arthritis Care & Research 64(12), pp. 1804-1810.