Prevalence and treatment of psoriasis in the United Kingdom: a population-based study.

OBJECTIVE To measure the prevalence and treatment of psoriasis in the United Kingdom. DESIGN Cross-sectional study to determine prevalence and cohort study to determine treatment patterns. SETTING Outpatient practices of general practitioners. PATIENTS We included in the analysis all patients who were registered with a general practitioner in the General Practice Research Database from 1987 to 2002. MAIN OUTCOME MEASURES The prevalence and treatment of psoriasis. RESULTS We identified 114 521 patients with psoriasis of a total population of 7 533 475 patients, yielding a prevalence of 1.5%. The prevalence of psoriasis increases more rapidly in young female patients compared with young male patients and declines significantly in patients 70 years and older, regardless of sex. Overall, 91.8% of patients with a diagnosis of psoriasis received a prescription for psoriasis treatment on or after the date of their first diagnostic code of psoriasis in the General Practice Research Database. Most of the patients (55.2%) received only 1 or 2 prescriptions for psoriasis in the first year after psoriasis was documented in the General Practice Research Database. CONCLUSIONS The epidemiology of psoriasis in the General Practice Research Database population is similar to that of other epidemiologic studies of psoriasis performed in the United Kingdom, the United States, and other Western countries. Psoriasis carries a substantial burden given its high prevalence and its associated need for prescription therapy. Additional studies are necessary to determine why the prevalence of psoriasis increases more rapidly in female patients and to determine why the prevalence decreases in patients 70 years and older.