title: The prevalence of actinic keratosis in patients visiting dermatologists in two hospitals in China.
abstract: BACKGROUND
  Actinic keratosis (AK) is one of the most common conditions treated by dermatologists in western countries. Studies have shown that AK prevalence in Europe, the U.S.A. and Australia is 4·5-60%. No data of AK prevalence in China has been reported.
  
  
  OBJECTIVE
  This study aimed to explore the prevalence of AK in patients visiting dermatologists in two hospitals in China.
  
  
  METHODS
  This study was conducted in the dermatology departments of two teaching hospitals (Peking University First Hospital, Beijing, and Fourth Military Medical University, Xi'an). All records for 5 years between 2008 and 2012 with clinically or pathologically diagnosed AKs were collected from the pathological databases of both hospitals. Data from these records were used to calculate the prevalence of AKs among patients who were seen by dermatologists in these hospitals. To estimate the reliability of data from the previous database, a cross-sectional study was conducted simultaneously in the two hospitals from 15 October to 8 December in 2012 after all dermatologists in the two departments were retrained through intensive courses on recognizing AK clinically.
  
  
  RESULTS
  The prevalence of total clinical AKs through 2008-2012 was 0·52% in 1 590 817 patient visits in the two hospitals. The yearly prevalence of clinical AKs was 0·30-1·20%. In the cross-sectional study, 72 437 clinical patients were screened and 76 patients (1·05%) were identified to have clinically recognized AK.
  
  
  CONCLUSIONS
  The overall prevalence of AKs in patients visiting dermatologists in the two hospitals in China was 0·52%, which is much lower than the prevalence in western countries.
authors.affiliation: Department of Dermatology, Beijing Tsinghua Changgung Hospital, Medical Center, Tsinghua University, No. 168 Litang Road, Dongxiaokou Town, Changping District, Beijing, 102218, China.|Department of Dermatology and Venereology, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
authors.forename: C Y
authors.initials: CY
authors.lastname: Li
authors.affiliation: Department of Dermatology, Civil Aviation General Hospital, No. 1, Chaowai, Gaojiajin, Beijing, 100123, China.
authors.forename: C M
authors.initials: CM
authors.lastname: Wen
authors.affiliation: Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
authors.forename: Y B
authors.initials: YB
authors.lastname: Wei
authors.affiliation: Department of Dermatology and Venereology, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China.
authors.forename: R Y
authors.initials: RY
authors.lastname: Li
authors.affiliation: Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
authors.forename: G
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Dermatology and Venereology, Peking University First Hospital, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, China.
authors.forename: P
authors.initials: P
authors.lastname: Tu
mesh_terms: D000368:Aged; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D055623:Keratosis, Actinic / Q000453:epidemiology* / Q000628:therapy; D008297:Male; D015995:Prevalence