Abstract: Canine immune mediated hemolytic anemia (IMHA) has a high mortality rate, especially in the immediate post-diagnosis period. In human medicine, high neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte ratios (PLR) are associated with a poor prognosis in patients with cancer and pulmonary thromboembolism. In veterinary medicine, NLR has shown promising prognostic potential in dogs with solid tumors or sepsis, but limited data is available in dogs with IMHA.
Retrospective evaluation of 225 medical records of dogs diagnosed with IMHA was performed at two referral hospitals. The effects of hematological parameters, NLR, PLR, monocyte-to-lymphocyte ratio (MLR), lymphocyte-to-platelet ratio (LPR), monocyte-to-neutrophil ratio (MNR), band-to-neutrophil ratio (BNR), neutrophil-to-platelet ratio (NPR) and neutrophil-to-platelet and lymphocyte ratio (NPLR) on survival to discharge, 1 month and 6 months, on the number of blood transfusions required, and on erythrocyte regeneration were assessed. Survival rate was 80%, 70% and 63% at discharge, 1 month, and 6 months, respectively. There was no significant association between any of the reported ratios and survival or number of blood transfusions. Elevated leukocyte (OR=1.04 [1.01-1.08], P=0.009,), neutrophil (OR=1.06 [1.02-1.11], P= 0.005), band-cell (OR=1.24 [1.01-1.51], P=0.037), and monocyte (OR=1.70 [1.21-2.37], P = 0.002) counts as well as elevated NLR (OR=1.04 [1.00-1.08], P=0.044) and MLR (OR=1.8 [1.18-2.60], P=0.005) were significantly associated with erythrocyte regeneration at presentation.
The various ratios investigated failed to predict outcomes or requirement for transfusions in dogs diagnosed with IMHA. Regeneration was associated with various hematology variables, likely indicating bone marrow simultaneous stimulation of erythroid, lymphoid and myeloid lines in IMHA patients.
