Smoking Compounds Psoriatic Arthritis

Patients with psoriatic arthritis who are also smokers have worse patient-reported disease features at baseline, and have a worse response than non-smokers to anti-tumor necrosis factor (TNF) treatment, a new study finds.

Researchers from Copenhagen University Hospital—who note that the impact of smoking on psoriatic arthritis has not been extensively studied—analyzed data from the DANBIO registry, which includes more than 90 percent of Danish patients receiving treatment with biologic medications. The authors studied 1,388 patients with psoriatic arthritis who had begun treatment with etanercept (Enbrel), infliximab (Remicade), or adalimumab (Humira). One-third of the patients were smokers, while 41 percent had never smoked, and 26 percent had smoked in the past but had since quit. While smoking did influence patient-reported disease features, the investigators saw less effect on objective measures such as swollen joint count and C-reactive protein level.
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Current smokers’ patient global scores were higher on a 100-mm visual analog scale, compared to patients who had never smoked (72 mm versus 68 mm), with smokers also registering higher fatigue scores (72 mm versus 63 mm), and worse functional status on the Health Assessment Questionnaire (1.1 versus 1).

In addition, smokers had lower rates of response on the American College of Rheumatology 20 percent and 50 percent improvement criteria at 6 months (24 percent compared to 33 percent, and 17 percent versus 24 percent). Smokers also had shorter disease duration—3 years versus 5 years—at the time of initiating anti-TNF therapy. This finding may suggest a more aggressive disease course among smokers, according to the authors.

Overall, treatment adherence was lower among current smokers, whose median time on treatment was 1.56 years, in comparison to 2.43 years for patients who had never smoked.

The researchers point out that patients who had stopped smoking more than 4 years before beginning treatment demonstrated very similar rates of adherence to treatment as those who had never smoked. This finding may indicate a gradual normalization of pathological processes and smoking-related behavior; a finding that is worth noting, the authors point out, as tobacco smoking is a potentially modifiable lifestyle factor.

—Mark McGraw

Reference

Hojgaard P, Glintborg B, et al. Association between tobacco smoking and response to tumour necrosis factor α inhibitor treatment in psoriatic arthritis: results from the DANBIO registry. Ann Rheum Dis. 2014.