title: Measuring disease prevalence: a comparison of musculoskeletal disease using four general practice consultation databases.
abstract: BACKGROUND
  Primary care consultation data are an important source of information on morbidity prevalence. It is not known how reliable such figures are.
  
  
  OBJECTIVE
  To compare annual consultation prevalence estimates for musculoskeletal conditions derived from four general practice consultation databases.
  
  
  METHODS
  Retrospective study of general practice consultation records.
  
  
  METHODS
  Three national general practice consultation databases: i) Fourth Morbidity Statistics from General Practice (MSGP4, 1991/92), ii) Royal College of General Practitioners Weekly Returns Service (RCGP WRS, 2001), and iii) General Practice Research Database (GPRD, 1991 and 2001); and one regional database (Consultations in Primary Care Archive, 2001).
  
  
  METHODS
  Age-sex standardized persons consulting annual prevalence rates for musculoskeletal conditions overall, rheumatoid arthritis, osteoarthritis and arthralgia were derived for patients aged 15 years and over.
  
  
  RESULTS
  GPRD prevalence of any musculoskeletal condition, rheumatoid arthritis and osteoarthritis was lower than that of the other databases. This is likely to be due to GPs not needing to record every consultation made for a chronic condition. MSGP4 gave the highest prevalence for osteoarthritis but low prevalence of arthralgia which reflects encouragement for GPs to use diagnostic rather than symptom codes.
  
  
  CONCLUSIONS
  Considerable variation exists in consultation prevalence estimates for musculoskeletal conditions. Researchers and health service planners should be aware that estimates of disease occurrence based on consultation will be influenced by choice of database. This is likely to be true for other chronic diseases and where alternative symptom labels exist for a disease. RCGP WRS may give the most reliable prevalence figures for musculoskeletal and other chronic diseases.
authors.affiliation: Primary Care Musculoskeletal Research Centre, Keele University, Keele. k.p.jordan@cphc.keele.ac.uk
authors.forename: Kelvin
authors.initials: K
authors.lastname: Jordan
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Clarke
authors.forename: Deborah P M
authors.initials: DP
authors.lastname: Symmons
authors.forename: Douglas
authors.initials: D
authors.lastname: Fleming
authors.forename: Mark
authors.initials: M
authors.lastname: Porcheret
authors.forename: Umesh T
authors.initials: UT
authors.lastname: Kadam
authors.forename: Peter
authors.initials: P
authors.lastname: Croft
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001071:Appointments and Schedules; D019992:Databases as Topic / Q000706:statistics & numerical data*; D005194:Family Practice / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D006113:United Kingdom / Q000453:epidemiology