title: Economic burden of chronic bronchitis in the United States: a retrospective case-control study.
abstract: BACKGROUND
  Chronic bronchitis (CB) is often misdiagnosed or diagnosed at a later stage of chronic obstructive pulmonary disease (COPD). We examined how this later diagnosis may impact health care costs and utilization during the 12 months prior to and 24 months post initial CB diagnosis.
  
  
  METHODS
  This retrospective case-control analysis used claims data from a large US database from July 1, 2003 through June 30, 2007. Patients with CB aged 40 years and older were propensity matched (N = 11,674) to patients without evidence of COPD or asthma by demographics, CB diagnosis quarter/year, and comorbidities. Group differences were assessed using Student's t-test and Pearson chi-square test statistics.
  
  
  RESULTS
  Six months prediagnosis, CB patients had higher frequencies of any hospitalization (9.6%, 6.7%; P < 0.05), emergency department/urgent care visits (13.3%, 6.7%; P < 0.05), and prescriptions (97.3%, 94.1%; P < 0.05). Six months postdiagnosis, CB patients had 5.6 times more hospitalizations (P < 0.05) and 3.1 times more emergency department/urgent care visits (P < 0.05) compared with controls. Mean total costs (US$) for CB patients 12 months prediagnosis were significantly higher than controls (months 12-7: $4212, $3826; P < 0.05; months 6-1: $5289, $4285; P < 0.05). CB patients had higher mean total costs ($8919; P < 0.05) 6 months postdiagnosis. Costs remained $2429 higher for CB patients 19-24 months postdiagnosis (P < 0.05).
  
  
  CONCLUSIONS
  Health care costs and utilization among CB patients are increased both prior to diagnosis and during the 2 years postdiagnosis. This study suggests that not accurately diagnosing CB early has a substantial impact on health care costs, and that the economic burden for CB patients remains elevated even after adjustment for comorbidities associated with COPD.
authors.affiliation: Division of Clinical and Outcomes Research, Lovelace Respiratory Research Institute, Kannapolis, NC 28081, USA. cblanchette@lrri.org
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Blanchette
authors.forename: Melissa H
authors.initials: MH
authors.lastname: Roberts
authors.forename: Hans
authors.initials: H
authors.lastname: Petersen
authors.forename: Anand A
authors.initials: AA
authors.lastname: Dalal
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Mapel
mesh_terms: D000368:Aged; D000553:Ambulatory Care / Q000191:economics; D029481:Bronchitis, Chronic / Q000175:diagnosis / Q000191:economics* / Q000628:therapy; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D016527:Drug Costs; D042241:Early Diagnosis; D004632:Emergency Medical Services / Q000191:economics; D005260:Female; D017048:Health Care Costs; D006760:Hospitalization / Q000191:economics; D006801:Humans; D008297:Male; D008875:Middle Aged; D018803:Models, Economic; D057216:Propensity Score; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States