title: Owner assessment in judging the efficacy of airway disease treatment.
abstract: BACKGROUND
  Efficacy of medications for recurrent airway obstruction is typically tested using clinical, cytological and lung function examinations of severely affected animals. These trials are technically challenging and may not adequately reflect the spectrum of disease and owner complaints encountered in clinical practice.
  
  
  OBJECTIVE
  To determine if owners of horses with chronic airway disease are better able to detect drug efficacy than a veterinarian who clinically examines horses infrequently.
  
  
  METHODS
  In a double-blinded randomised controlled trial, owners and a veterinarian compared the efficacy of dexamethasone (0.1 mg/kg bwt per os, q. 24 h, for 3 weeks; n = 9) to placebo (n = 8) in horses with chronic airway disease. Before and after treatment, owners scored performance, breathing effort, coughing and nasal discharge using a visual analogue scale (VAS). The clinician recorded vital parameters, respiratory distress, auscultation findings, cough and nasal discharge, airway mucus score, bronchoalveolar lavage fluid (BALF) cytology and arterial blood gases.
  
  
  RESULTS
  The VAS score improved significantly in dexamethasone- but not placebo-treated horses. In contrast, the clinician failed to differentiate between dexamethasone- and placebo-treated animals based on clinical observations, BALF cytology or endoscopic mucus score. Respiratory rate (RR) and arterial oxygen pressure (PaO(2)) improved with dexamethasone but not placebo.
  
  
  CONCLUSIONS
  In the design of clinical trials of airway disease treatments, more emphasis should be placed on owner-assessed VAS than on clinical, cytological and endoscopic observations made during brief examinations by a veterinarian. Quantifiable indicators reflecting lung function such as RR and PaO(2) provide a good assessment of drug efficacy.
authors: Department of Large Animal Clinical Sciences, Michigan State University, USA.
authors: V
authors: V
authors: Gerber
authors: H C
authors: HC
authors: Schott Ii
authors: N E
authors: NE
authors: Robinson