Drug Survival of Biological Therapies in Smokers and Non-Smokers With Psoriasis: A Retrospective Cohort Study Using Data From the Australasian Psoriasis Registry

Abstract

Background

Smoking is a modifiable risk factor that increases the likelihood of developing psoriasis and the severity of the disease. In recent years, biological therapies have transformed the management of psoriasis. There is conflicting evidence about whether smoking affects the efficacy of biologics. The aim of this study was to assess drug survival and the efficacy of the first biologic for psoriasis in smokers compared with non-smokers.

Methods

This was a retrospective cohort study using data from the Australasian Psoriasis Registry. Participants with psoriasis who met Pharmaceutical Benefits Scheme eligibility criteria for a biologic (n = 395) were included. Associations between smoking and drug survival or Psoriasis Area and Severity Index (PASI) response were assessed using univariable and multivariable Cox Proportional Hazards regression, controlling for confounders including sex, obesity, psoriatic arthritis, biologic class and baseline PASI.

Results

The prevalence of current smoking was 24.6% and former smoking was 18.5%. On univariable analysis, smokers were 34% more likely to discontinue treatment compared with non-smokers (p = 0.039), were 27% less likely to attain PASI90 (p = 0.037) and 33% less likely to attain PASI100 (p = 0.038). On multivariable analysis, the association between smoking and reduced drug survival was no longer statistically significant. Multiple factors, including obesity, female sex, psoriatic arthritis and higher PASI scores, were risk factors for drug discontinuation.

Conclusions

This analysis illustrated that multiple factors are involved in drug survival, and smoking was not an independent risk factor for drug discontinuation. This study provides a rationale for future studies examining the effect of lifestyle modification on the efficacy of biological therapies in psoriasis.