title: Presentation of respiratory symptoms prior to diagnosis in general practice: a case-control study examining free text and morbidity codes.
abstract: OBJECTIVE
  General practitioners can record patients' presenting symptoms by using a code or free text. We compared breathlessness and wheeze symptom codes and free text recorded prior to diagnosis of ischaemic heart disease (IHD), chronic obstructive pulmonary disease (COPD) and asthma.
  
  
  METHODS
  A case-control study.
  
  
  METHODS
  11 general practices in North Staffordshire, UK, contributing to the Consultations in Primary Care Archive consultation database.
  
  
  METHODS
  Cases with an incident diagnosis of IHD, COPD or asthma in 2010 were matched to controls (four per case) with no such diagnosis. All prior consultations with codes for breathlessness or wheeze symptoms between 2004 and 2010 were identified. Free text of cases and controls were also searched for mention of these symptoms.
  
  
  RESULTS
  592 cases were identified, 194 (33%) with IHD, 182 (31%) with COPD and 216 (37%) with asthma. 148 (25%) cases and 125 (5%) controls had a prior coded consultation for breathlessness. Prevalence of a prior coded symptom of breathlessness or wheeze was 30% in cases, 6% in controls. Median time from first coded symptom to diagnosis among cases was 57 weeks. After adding symptoms recorded in text, prevalence rose to 62% in cases and 25% in controls. Median time from first recorded symptom increased to 144 weeks. The associations between diagnosis of cases and prior symptom codes was strong IHD relative risk ratio (RRR) 3.21 (2.15 to 4.79); COPD RRR 9.56 (6.74 to 13.60); asthma RRR 10.30 (7.17 to 14.90).
  
  
  CONCLUSIONS
  There is an association between IHD, COPD and asthma diagnosis and earlier consultation for respiratory symptoms. Symptoms are often noted in free text by GPs long before they are coded. Free text searching may aid investigation of early presentation of long-term conditions using GP databases, and may be an important direction for future research.
authors.affiliation: Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, UK.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hayward
authors.affiliation: Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, UK.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Croft
authors.affiliation: Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, UK.
authors.forename: Kelvin P
authors.initials: KP
authors.lastname: Jordan
mesh_terms: D000368:Aged; D001249:Asthma / Q000150:complications / Q000175:diagnosis*; D016022:Case-Control Studies; D004417:Dyspnea / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D058006:General Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000175:diagnosis*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis*; D012017:Referral and Consultation; D012135:Respiratory Sounds / Q000175:diagnosis*; D006113:United Kingdom
keywords: EPIDEMIOLOGY; STATISTICS & RESEARCH METHODS