title: Impact of smoking on response to systemic treatment in patients with psoriasis: a retrospective case-control study.
abstract: BACKGROUND
  Smoking is a well-established risk factor for developing psoriasis and is associated with development of more severe disease. Smoking cessation does not appear to result in clinical improvement of psoriasis. Whether smoking in patients with psoriasis impacts response to systemic therapy is unknown.
  
  
  OBJECTIVE
  To determine whether smokers with psoriasis with or without psoriatic arthritis respond to systemic agents as well as nonsmokers do.
  
  
  METHODS
  We performed a retrospective review of patients with moderate-to-severe psoriasis with or without psoriatic arthritis seen at our institution, who were either active smokers or nonsmokers, and calculated changes in Physician's Global Assessment (PGA) scores after 3-16 months of systemic treatment. We also calculated the average number of systemic treatments tried per patient.
  
  
  RESULTS
  Sixty-six patients (46 nonsmokers, 20 smokers) met our inclusion criteria. Changes in PGA scores between baseline and 3-16 months after initiation of systemic treatment did not significantly differ between smokers and nonsmokers, nor did the average number of systemic treatments tried per patient. We detected a borderline significant trend in the percentage of patients who had significant outcomes after treatment, with a higher percentage of patients smoking < 10 cigarettes daily achieving target PGA scores compared with those smoking > 10 cigarettes daily. Limitations of our study include its retrospective nature and the relatively small number of patients meeting our inclusion criteria.
  
  
  CONCLUSIONS
  In our retrospectively studied cohort, smoking did not affect response to systemic treatment in patients with psoriasis. A prospective study examining the complex relationship between smoking, psoriasis and response to systemic therapy is warranted to explore this association better.
authors.affiliation: Royal College of Surgeons, 123 St Stephen's Green, Dublin 2, Ireland.
authors.forename: C E
authors.initials: CE
authors.lastname: Kinahan
authors.forename: S
authors.initials: S
authors.lastname: Mazloom
authors.forename: A P
authors.initials: AP
authors.lastname: Fernandez
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003879:Dermatologic Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000188:drug therapy*; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003879:Dermatologic Agents