Smoking impairs response to inflammatory back arthritis drugs

The response to biological drugs used to treat inflammatory arthritis affecting the lower back is impaired by smoking, says research in the Annals of the Rheumatic Diseases.
Axial spondyloarthritis (AxSpA) is a relatively newly defined form of arthritis and until now it hasn’t been clear what impact smoking has on the drugs used to treat it.
So experts tracked the treatment response to biological drugs (tumour necrosis factor inhibitors) in just under 500 people with confirmed AxSpA, of whom 62% were smokers and 38% were non-smokers. Age, sex, symptom duration, weight and exercise were all taken into account.
Results
Having smoked in the past didn’t affect the response to treatment, but current smoking did.
Compared with the non-smokers, current smokers responded less well to their drug treatment and achieved smaller reductions in scores that monitored improvement in symptoms. This difference was particularly noticeable among those who had higher levels of an inflammatory marker called C reactive protein (CRP) to begin with.
Between 10% and 20% fewer current smokers than non-smokers achieved a 50% fall in their baseline disease activity score after one year of treatment.
The researchers suggest that smoking could prompt a rise in CRP or increase pain by interfering with the neural processing of sensory information or starving tissues of oxygen, but highlight that more studies are needed.

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Image credit: SuperFantastic