title: Psoriasis and the risk of incident diabetes mellitus: a population-based study.
abstract: BACKGROUND
  Cross-sectional studies, mostly in hospitalized patients, reported a possible positive association between psoriasis and diabetes mellitus (DM). However, information on the temporal relation is scarce, and incidence rates of new-onset DM in patients with psoriasis are lacking.
  
  
  OBJECTIVE
  To assess and compare incidence rates of new-onset DM between patients with psoriasis and a comparison group without psoriasis, and to explore the role of psoriasis severity and body mass index (BMI).
  
  
  METHODS
  We conducted a follow-up study with a nested case-control analysis within the U.K.-based General Practice Research Database. The study population consisted of patients with a first-time diagnosis of psoriasis between 1994 and 2005 and a matched group of psoriasis-free patients. We used psoriasis duration and treatment as proxy for disease severity, and we applied conditional logistic regression to obtain odds ratios (ORs) with 95% confidence intervals (CIs).
  
  
  RESULTS
  Within the study population of 65 449 patients we identified 1061 incident cases of DM. Of these, 59% had a history of psoriasis, yielding a crude incidence rate ratio of 1.36 (95% CI 1.20-1.53). The adjusted OR for patients with >or=2 years disease duration and >2 prescriptions per year for oral psoriasis treatment was 2.56 (95% CI 1.11-5.92). In an analysis restricted to patients with normal BMI, the adjusted OR was 2.02 (95% CI 1.31-3.10).
  
  
  CONCLUSIONS
  In this large observational study the risk of incident DM was increased for patients with psoriasis as compared with a psoriasis-free comparison group. The risk increased with psoriasis duration and severity and was not driven by high BMI alone.
authors.affiliation: Basel Pharmacoepidemiology Unit, Division of Clinical Pharmacology and Toxicology, University Hospital Basel, Hebelstrasse 2, CH-4031 Basel, Switzerland.
authors.forename: Y B
authors.initials: YB
authors.lastname: Brauchli
authors.forename: S S
authors.initials: SS
authors.lastname: Jick
authors.forename: C R
authors.initials: CR
authors.lastname: Meier
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011565:Psoriasis / Q000175:diagnosis / Q000453:epidemiology*; D012306:Risk; D012720:Severity of Illness Index; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult