SAN FRANCISCO — Preliminary research suggests that rheumatoid arthritis patients who quit smoking may experience fewer swollen and tender joints and improved C-reactive protein levels, among other measures of improved disease activity, according to a presentation at the annual meeting of the American College of Rheumatology.
In the first known study of the impact of active smoking cessation in RA, Dr. Mark C. Fisher and his associates at the New York University Medical Center Hospital for Joint Diseases examined markers of disease progression in patients who quit smoking, compared with those who continued to smoke.
The cross-sectional study examined records for 16,521 patients with active rheumatoid arthritis, of whom 2,328 were current smokers at baseline. At an average follow-up of 3.5 years, 328 of these smokers had quit successfully, according to at least 2 consecutive self-reports at clinic visits spaced about 3 months apart.
At baseline, no differences were seen between the patients who eventually quit and those who continued to smoke in terms of disease duration, rheumatoid factor or cyclic citrullinated peptide (CCP) status, or medication type or use.
Nonetheless, at their final clinic visit for the study, the smokers who had quit had a lower mean Clinical Disease Activity Index (14 versus 11.5), which reflected a reduced number of swollen and tender joints and lower C-reactive protein level, a marker of inflammation.
When this difference was adjusted for potentially confounding variables, the relationship remained “statistically significant, and probably clinically significant as well,” but less powerful, said Dr. Fisher, a research fellow, in an interview at the meeting.
An intriguing finding within the adjusted data was the fact that quitters with more severe disease at baseline appeared to have the greatest improvement on their Clinical Disease Activity Index scores as well as patient- and physician-assessed global improvement. “Remission data were even more impressive,” said Dr. Fisher.
In an unadjusted model, 12.3% of patients who continued to smoke were in remission at the final follow-up visit, compared with 18.6% of those who quit. The difference remained “highly statistically significant” even after adjustment for potentially confounding variables. To find that quitters were 1.49 times more likely to go into remission is powerful, he said, even in a “snapshot” cross-sectional study.
A longitudinal study is being planned, said Dr. Fisher. He reported no disclosures with regard to funding of the study.
Quitters with more severe diseaseat baseline had the greatest improvement on their disease activity scores. DR. FISHER