| The goal of this dissertation was to identify risk and prognostic factors in dogs with immune-mediated hemolytic anemia (IMHA). Part one sought to obtain the one-year incidence in a major California metropolitan region and describe the characteristics of the cases seen in private practices. Forty-eight cases from the Sacramento area were reported during the year under study; detailed information was provided on 33 confirmed cases. The annual rate of confirmed cases of IMHA in this region was 0.012%, or 12 cases per 100,000 dogs seen at private animal hospitals per year. The findings are compatible with the conclusion that IMHA remains a relatively rare disease in the population of dogs seen in private veterinary practice.; A retrospective cohort study of dogs seen at the University of California Veterinary Medical Teaching Hospital with primary IMHA between 1998--2001 was undertaken to evaluate the effects of presenting clinical signs and treatment options on survival. A Cox proportional hazards regression model was used to evaluate the putative factor effects. Four presenting factors affected the mortality among patients. As patient weight increased, mortality from IMHA increased. Survival was inversely related to the square root of age. Nonregenerative anemia had an adverse affect on patient survival. Mortality was inversely related to the red blood cell count. Treatments were evaluated, but because this was a non-randomized study, valid conclusions could not be made about treatment effectiveness.; In order to evaluate the relationship between vaccination and IMHA, a case-control study and a case-crossover study were performed. One hundred eighty-eight dogs from California, Michigan, Minnesota, Illinois, and Virginia with idiopathic IMHA, and 145 controls from California, Michigan, Minnesota, and Illinois were included. The case-control and case-crossover analyses employed a series of time windows (1--6 weeks) to characterize the effect period of vaccination, if any, on the acute onset of IMHA. There was a trend of increasing effect observed from 1--3 weeks after vaccination, with a diminishing of that effect out to 6 weeks in both the case-control and case-crossover analyses. Only the association of recent rabies vaccine and the onset of IMHA was statistically significant. |
