Systematic Review of Prognostic Factors for Mortality in Dogs with Immune‐mediated Hemolytic Anemia

BACKGROUND Treatment of dogs with primary immune-mediated hemolytic anemia (IMHA) is difficult and frequently unrewarding. Prognostic factors have been evaluated in a number of previous studies, and identification of such factors would be beneficial to enable selection of appropriate therapeutic regimens and supportive care. OBJECTIVES The aim of the current study was to undertake a critical appraisal of the risk of bias in evidence relating to prognostic indicators for mortality in dogs with IMHA. ANIMALS Three hundred and eighty client-owned dogs with spontaneous primary idiopathic IMHA reported in 6 previous studies. METHODS A systematic review was conducted to evaluate evidence relating to prognostic factors for mortality in dogs with primary IMHA. Search tools were employed to identify articles and a validated appraisal tool was used to assess the quality of individual studies by considering inclusion and exclusion criteria, measurement of prognostic, outcome and confounding variables, and statistical methods. RESULTS Few studies evaluated prognostic indicators for IMHA in dogs, and all of these suffered from methodologic flaws in at least 1 major area. Fifteen different variables were identified as prognostic indicators, with 2 variables identified by >1 study. CONCLUSIONS AND CLINICAL IMPORTANCE There are few pieces of high-quality evidence available to enable estimation of prognosis for dogs presenting with primary IMHA.