Smoking Increases RA Disease Activity Over Time
Smoking is associated with higher levels of disease activity over time in patients with rheumatoid arthritis (RA), according to a recent study.
Findings from the study were presented at the ACR/ARHP Annual Meeting, which is taking place from November 3 to 8, 2017, in San Diego, California.
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Although the relationship between smoking and RA has been established, less is known about how smoking affects RA disease activity.
From 2013 to 2017, the researchers assessed the electronic health record data of 291 patients with a diagnosis of RA and at least 2 visits to a clinic within 12 months. Mean patient age was 59.2 years, and 11% of patients were smokers. Time points during the study occurred in intervals of 3 months. Smoking and additional covariates including sex, race/ethnicity, age, obesity (body mass index [BMI] of more than 30 kg/m2), and medications were assessed at each time point.
The effect of smoking on disease activity, which was measured by the clinical disease activity index (CDAI) and patient global assessment (PGA) at 30 months, was estimated via longitudinal targeted maximum likelihood.
Following adjustment for covariates, results indicated that smoking was associated with a CDAI score of 16.67 at 30 months vs 12.05 for non-smoking. Additionally, smoking was associated with a PGA score of 40.53, compared with 45.42 for non-smoking.
“Smoking may be causally associated with higher levels of disease activity over time as measured by the CDAI,” the researchers concluded. “Differences in CDAI between smokers and non-smokers are likely clinically meaningful for individuals with low to moderate disease activity. Patient reported outcomes such as PGA may be influenced by other factors such as depression. These methods may be useful for investigations of additional exposures on longitudinal outcome measures in rheumatologic disease.”
—Christina Vogt
Reference:
Gianfrancesco M, Trupin L, Shiboski S, et al. Smoking is causally associated with disease activity in rheumatoid arthritis. Paper presented at: ACR/ARHP Annual Meeting; November 3-8, 2017; San Diego, CA. http://acrabstracts.org/abstract/smoking-is-causally-associated-with-disease-activity-in-rheumatoid-arthritis/.