Background/Purpose: Smoking is an important environmental risk factor for development of rheumatoid arthritis (RA). Smoking has been linked to lower rates of disease remission, incomplete response to DMARD therapy, and elevated serum levels of pro-inflammatory cytokines. Former smokers respond equally well to DMARD treatment as never smokers. In established RA patients, it is unknown if smoking cessation improves RA-associated outcomes. We aimed to investigate the association of tobacco use and disease activity in established RA patients. We hypothesized that current tobacco use in established RA is associated with increased DAS28-CRP and is affected by RA-associated comorbidities.

Methods: We performed a case control study on 95 patients with RA. Patients were consented and enrolled in the Penn State Investigation of Remission in Rheumatoid Arthritis cohort. Disease activity was measured by DAS28-CRP. Smoking was categorized as current, former or never status. Chi-square (X²) or Fisher’s exact test were used to test for differences between categorical variables, and ANOVA or Kruskal-Wallis test were used for continuous variables. The primary outcome was the association of smoking status with DAS28-CRP. Multivariable linear regression was performed with covariates including age, education, pack years, disability as measured by the modified health assessment questionnaire (MHAQ), nodules, hypertension, periodontitis, and disease duration.

Results: RA subjects had an average age of 55.5 years, 74% were female and > 90% were Caucasian. Subjects had established RA with a mean disease duration of 10.9 years, 87% were seropositive, and mean DAS28-CRP was 3.36. 89.3% of patients met the 2010 ACR/EULAR classification criteria for RA. 19% percent were current smokers and 36% were former smokers, who were 10 years older than current smokers (p<0.05). Mean DAS28-CRP was significantly higher (p=0.003) in current smokers (4.40) compared to former (3.26) and never (2.95) smokers. Current smokers had a lower odds of being in remission than never smokers (OR=0.14, p=0.02). Rheumatoid nodules were more prevalent in current smokers (p=0.06). Level of education was inversely associated with DAS28-CRP (p=0.008). Median MHAQ scores were significantly higher in current smokers (0.75) than former smokers (0; p=0.02). MHAQ scores were strongly associated with DAS28-CRP (p<0.0001). There was no difference in DAS28-CRP scores between smoking groups when controlled for MHAQ score, education, and periodontitis.

Conclusion: Current smokers with established RA have higher disease activity and are significantly less likely to be in remission. Smoking status and RA disease activity are strongly associated with disability, education level, and periodontal scores, implying both a socioeconomic and pathophysiologic basis for this association. Effects of smoking cessation on RA outcomes would be of interest.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/higher-disease-activity-in-current-smokers-with-established-ra-is-it-disease-damage-or-disability/