title: Why patients visit their doctors: assessing the most prevalent conditions in a defined American population.
abstract: OBJECTIVE
  To describe the prevalence of nonacute conditions among patients seeking health care in a defined US population, emphasizing age, sex, and ethnic differences.
  
  
  METHODS
  The Rochester Epidemiology Project (REP) medical records linkage system was used to identify all residents of Olmsted County, Minnesota, on April 1, 2009, who had consented to review of their medical records for research (142,377 patients). We then electronically extracted all International Classification of Diseases, Ninth Revision codes noted in the records of these patients by any health care institution between January 1, 2005, and December 31, 2009. We grouped International Classification of Diseases, Ninth Revision codes into clinical classification codes and then into 47 broader disease groups associated with health-related quality of life. Age- and sex-specific prevalence was estimated by dividing the number of individuals within each group by the corresponding age- and sex-specific population. Patients within a group who had multiple codes were counted only once.
  
  
  RESULTS
  We included a total of 142,377 patients, 75,512 (53%) of whom were female. Skin disorders (42.7%), osteoarthritis and joint disorders (33.6%), back problems (23.9%), disorders of lipid metabolism (22.4%), and upper respiratory tract disease (22.1%, excluding asthma) were the most prevalent disease groups in this population. Ten of the 15 most prevalent disease groups were more common in women in almost all age groups, whereas disorders of lipid metabolism, hypertension, and diabetes were more common in men. Additionally, the prevalence of 7 of the 10 most common groups increased with advancing age. Prevalence also varied across ethnic groups (whites, blacks, and Asians).
  
  
  CONCLUSIONS
  Our findings suggest areas for focused research that may lead to better health care delivery and improved population health.
authors.affiliation: Division of Epidemiology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: St Sauver
authors.forename: David O
authors.initials: DO
authors.lastname: Warner
authors.forename: Barbara P
authors.initials: BP
authors.lastname: Yawn
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Jacobson
authors.forename: Michaela E
authors.initials: ME
authors.lastname: McGree
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Pankratz
authors.forename: L Joseph
authors.initials: LJ
authors.lastname: Melton
authors.forename: Véronique L
authors.initials: VL
authors.lastname: Roger
authors.forename: Jon O
authors.initials: JO
authors.lastname: Ebbert
authors.forename: Walter A
authors.initials: WA
authors.lastname: Rocca
mesh_terms: D017677:Age Distribution; D001416:Back Pain / Q000453:epidemiology*; D050171:Dyslipidemias / Q000453:epidemiology*; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D038801:International Classification of Diseases; D007592:Joint Diseases / Q000453:epidemiology*; D008297:Male; D008498:Medical Record Linkage; D008910:Minnesota / Q000453:epidemiology; D015995:Prevalence; D011788:Quality of Life; D012140:Respiratory Tract Diseases / Q000453:epidemiology*; D012871:Skin Diseases / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology