title: (Correcting) misdiagnoses of asthma: a cost effectiveness analysis.
abstract: BACKGROUND
  The prevalence of physician-diagnosed-asthma has risen over the past three decades and misdiagnosis of asthma is potentially common.
  
  
  OBJECTIVE
  to determine whether a secondary-screening-program to establish a correct diagnosis of asthma in those who report a physician diagnosis of asthma is cost effective.
  
  
  METHODS
  Randomly selected physician-diagnosed-asthmatic subjects from 8 Canadian cities were studied with an extensive diagnostic algorithm to rule-in, or rule-out, a correct diagnosis of asthma. Subjects in whom the diagnosis of asthma was excluded were followed up for 6-months and data on asthma medications and heath care utilization was obtained. Economic analysis was performed to estimate the incremental lifetime costs associated with secondary screening of previously diagnosed asthmatic subjects. Analysis was from the perspective of the Canadian healthcare system and is reported in Canadian dollars.
  
  
  RESULTS
  Of 540 randomly selected patients with physician diagnosed asthma 150 (28%; 95%CI 19-37%) did not have asthma when objectively studied. 71% of these misdiagnosed patients were on some asthma medications. Incorporating the incremental cost of secondary-screening for the diagnosis of asthma, we found that the average cost savings per 100 individuals screened was $35,141 (95%CI $4,588-$69,278).
  
  
  CONCLUSIONS
  Cost savings primarily resulted from lifetime costs of medication use averted in those who had been misdiagnosed.
authors: University of Ottawa, and The Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada. spakhale@ohri.ca
authors: Smita
authors: S
authors: Pakhale
authors: Amanda
authors: A
authors: Sumner
authors: Douglas
authors: D
authors: Coyle
authors: Katherine
authors: K
authors: Vandemheen
authors: Shawn
authors: S
authors: Aaron
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