title: Health service utilisation for anogenital warts in Ontario, Canada prior to the human papillomavirus (HPV) vaccine programme introduction: a retrospective longitudinal population-based study.
abstract: OBJECTIVE
  Trends in occurrence of anogenital warts (AGWs) can provide early evidence of human papillomavirus (HPV) vaccination programme impact on preventing HPV infection and HPV-induced lesions. The objective of this study was to provide a baseline of AGW epidemiology in Ontario prior to the introduction of the publicly-funded school-based HPV vaccination programme in September 2007.
  
  
  METHODS
  As a retrospective longitudinal population-based study, we used health administrative data as a proxy to estimate incident AGWs and total health service utilisation (HSU) for AGWs for all Ontario residents 15 years and older with valid health cards between 1 April 2003 and 31 March 2007.
  
  
  METHODS
  The outcome of interest was AGW healthcare utilisation identified using the International Classification of Diseases, 10th revision (ICD-10) diagnostic code for AGWs, as well as an algorithm for identifying AGW physician office visits in a database with a unique system of diagnostic and procedural codes. An AGW case was considered incident if preceded by 12 months without HSU for AGWs. Time trends by age group and sex were analysed.
  
  
  RESULTS
  Between fiscal years 2003 and 2006, we identified 123,247 health service visits for AGWs by 51,436 Ontario residents 15 years and older. Incident AGWs peaked in females and males in the 21-23 year age group, at 3.74 per 1000 and 2.81 per 1000, respectively. HSU for AGWs peaked in females and males within the 21-23 year age group, at 9.34 per 1000 and 7.22 per 1000, respectively.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first population-based study of AGW incidence and HSU in Ontario. The sex and age distribution of individuals with incident and prevalent AGWs in Ontario was similar to that of other provinces before HPV vaccine programme implementation in Canada.
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada.
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Guerra
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Rosella
authors.affiliation: Department of Family and Community Medicine, University of Toronto, Ontario, Canada Women's College Hospital and Women's College Research Institute, Toronto, Ontario, Canada.
authors.forename: Sheila
authors.initials: S
authors.lastname: Dunn
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Wilson
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Chen
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Shelley L
authors.initials: SL
authors.lastname: Deeks
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003218:Condylomata Acuminata / Q000453:epidemiology*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009819:Office Visits / Q000706:statistics & numerical data; D009864:Ontario; D030361:Papillomavirus Infections / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000627:therapeutic use*; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D017678:Sex Distribution; D014611:Vaccination / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D053918:Papillomavirus Vaccines
keywords: EPIDEMIOLOGY; GENITOURINARY MEDICINE; SEXUAL MEDICINE