Risk factors for laryngeal hemiplegia in the horse

Abstract

Hospital data from the Veterinary Medical Data Base were obtained for January 1970 to June 1986. Data were from 18 North American veterinary teaching hospitals. Patients diagnosed with laryngeal hemiplegia were identified. In order to determine the frequency of diagnosis, statistics were gathered for patient-years-at-risk. The independent risks of age, sex, and breed on the hospital prevalence were determined. Laryngeal hemiplegia was diagnosed in 2798 horse rrepresenting 29 breeds. The male risk compared with females (OR = 1) was 2.7. Laryngeal hemiplegia was diagnosed significantly more often in three breeds of draft horses. Thoroughbreds, and American Saddlebreds; and significantly less often in Arabians, Appaloosas, American Paints, and American Quarter Horses. Standardbred horses and Tennessee Walking horses were seen about as frequently as they were represented in the hospital population. Using the proportion of cases-to-population seen at 2–3 years of age as the standard reference point (OR =1 ), Thoroughbreds showed a peak hospital prevalence at 2–3 years of age; thereafter their cause specific accession rate decreased. Other breeds, particularly the draft horses, showed an increasing rate of diagnosis over 3 years of age. The peak age ofdiagnosis for draft animals was 7–9 years; for the Standardbred and the American Quarter Horse, it was 4–6 years.