Idiopathic immune-mediated hemolytic anemia: treatment outcome and prognostic factors in 149 dogs.
BACKGROUND
Canine idiopathic immune-mediated hemolytic anemia (IMHA) is associated with a high mortality, especially in the 1st 2 weeks after diagnosis despite treatment.


OBJECTIVE
To determine treatment outcome and identify prognostic variables in order to define areas of future research.


METHODS
One hundred forty-nine dogs with hematocrit <30% and either a positive Coombs' test or spherocytosis and with no evidence of disease that can trigger IMHA were included.


METHODS
Retrospective cohort study. All dogs were treated with prednisolone and azathioprine according to a standard protocol. Survival analysis was performed by the Kaplan-Meier method. Variables recorded at the time of diagnosis were tested as possible prognostic variables in a univariate and multivariate Cox proportional hazard model.


RESULTS
The main predictors for mortality in dogs with idiopathic IMHA are the presence of increased plasma urea concentration, bands, thrombocytopenia, and petechiae at the time of diagnosis. The estimated Kaplan-Meier half-year survival was 72.6% (95% confidence interval [CI]: 64.9-81.3%). Mortality occurred mostly within the 1st 2 weeks. Cox proportional hazards analysis indicated that increased plasma urea concentration, icterus, and petechiae were the major independent predictors of mortality in the 1st 2 weeks. In most dogs that survived IMHA, a 3-month protocol of azathioprine with prednisolone maintained clinical remission. The estimated half-year survival for dogs that survived the 1st 2 weeks was 92.5% (95% CI: 86-99.3%).


CONCLUSIONS
If the dogs survived IMHA, a 3-month protocol of prednisolone and azathioprine was effective with regard to survival and clinical outcome. Future research should be directed at identifying whether thrombotic tendency in dogs with IMHA is the main contributor to the development of increased plasma urea concentration, icterus, thrombocytopenia, and petechiae.
Piek
C J
CJ
Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands. c.j.piek@uu.nl
Junius
G
G
Dekker
A
A
Schrauwen
E
E
Slappendel
R J
RJ
Teske
E
E
D000744:Anemia, Hemolytic, Autoimmune / Q000401:mortality / Q000628:therapy / Q000662:veterinary*; D000818:Animals; D001379:Azathioprine / Q000627:therapeutic use*; D001803:Blood Transfusion / Q000662:veterinary; D015331:Cohort Studies; D004283:Dog Diseases / Q000276:immunology / Q000401:mortality / Q000628:therapy*; D004285:Dogs; D004359:Drug Therapy, Combination; D005260:Female; D005440:Fluid Therapy; D005938:Glucocorticoids / Q000627:therapeutic use*; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D011239:Prednisolone / Q000627:therapeutic use*; D011379:Prognosis; D016016:Proportional Hazards Models; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome
D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D011239:Prednisolone; D001379:Azathioprine