title: Adherence to statins and the risk of psoriasis: a population-based cohort study.
abstract: BACKGROUND
  Statins have been shown to downregulate immune mechanisms activated in psoriasis. However, previous studies on their potential role in preventing psoriasis have yielded conflicting results.
  
  
  OBJECTIVE
  To assess the relationship between adherence to statins and the risk of psoriasis.
  
  
  METHODS
  This retrospective cohort study included 205,820 health plan enrollees in Israel (mean age 55 years; 54·1% women) who initiated statin treatment from January 1998 through to September 2009. Adherence to statins, measured by the proportion of days covered (PDC), throughout the entire follow-up period (mean 6·2 years) was recorded. Diagnosis codes of psoriasis were assigned by a dermatologist or rheumatologist, or at discharge from hospital.
  
  
  RESULTS
  During 1·28 million person-years (PY) of follow-up (median 5·74 years per person; interquartile range 3·78-8·36), 5615 cases of psoriasis (incidence density rate 4·4 per 1000 PY) were recorded. Compared with patients who did not adhere to statins (PDC < 20%), patients covered by statins for 40-59% of the time had a significantly lower risk of psoriasis (P < 0·05), with hazard ratios (HRs) of 0·84 and 0·74 among men and women, respectively. Among patients who adhered better to statins (PDC ≥ 80%), HRs were 0·88 (95% CI 0·79-0·98) and 1·00 (95% CI 0·90-1·11) among men and women, respectively.
  
  
  CONCLUSIONS
  The results of the current study suggest that high and long-term adherence to statins is not associated with a meaningful reduction in the risk of developing psoriasis.
authors.affiliation: Medical Division, Maccabi Healthcare Services, Tel Aviv, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: G
authors.initials: G
authors.lastname: Chodick
authors.affiliation: Medical Division, Maccabi Healthcare Services, Tel Aviv, Israel.|Faculty of Health Sciences, Ben-Gurion University of the Negev, Negev, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Weitzman
authors.affiliation: Medical Division, Maccabi Healthcare Services, Tel Aviv, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: V
authors.initials: V
authors.lastname: Shalev
authors.affiliation: Medical Division, Maccabi Healthcare Services, Tel Aviv, Israel.
authors.forename: C
authors.initials: C
authors.lastname: Weil
authors.affiliation: Faculty of Health Sciences, Ben-Gurion University of the Negev, Negev, Israel.|Department of Medicine B, Sheba Medical Center, Tel HaShomer, Israel.
authors.forename: H
authors.initials: H
authors.lastname: Amital
mesh_terms: D000328:Adult; D000368:Aged; D063506:Ageism; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000453:epidemiology / Q000517:prevention & control*; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult; D016903:Drug Monitoring
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors