Journal Scan: Is there a "best way" to treat immune-mediated hemolytic anemia in dogs?

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Why they did it

With a variety of corticosteroids and other drugs available to treat dogs with immune-mediated hemolytic anemia (IMHA), some insight into what to reach for first would be beneficial.

What they did

The authors conducted a systematic literature review (1980-2011) to evaluate the current evidence about the optimal immunosuppressive regimen for dogs with IMHA. Studies were included if they involved cases of primary idiopathic IMHA and had outcome data of therapeutic regimens used. Studies in which survival data were categorized by treatment or that contained fewer than five cases were not included.

Evidence presented in the studies was graded as follows:

A

Blinded randomized controlled trial comparing two treatment interventions

B

Controlled trial lacking either blinding or randomization

C

Prospective cohort study

D

Prospective case control study

E

Retrospective cohort or case control study

F

Prospective study with single intervention

G

Retrospective case series with single intervention

1

> 50 cases per group

2

21 to 50 cases per group

3

10 to 49 cases per group

4

< 10 cases per group

What they found

Overall, 19 studies were included in the review and reported data from 843 cases of IMHA. Only four (21%) of the studies were controlled trials with evidence grades of A or B. In four studies, the basis for the diagnosis of IMHA was unclear.

In terms of treatment, in nine of the studies (47%), the treatment regimens were graded as "clearly defined and complete." And in eight of the studies (42%), the treatment regimens were graded as "clearly defined but incomplete" since they did not state the duration of treatment. The dose rates of key drugs were not provided in the remaining two studies, and the regimens were deemed unclear.

While the dose and formulation varied, corticosteroids were used in every case of IMHA evaluated. The doses for prednisone or prednisolone ranged between 1 and 8 mg/kg/day, while the dose of dexamethasone ranged between 0.2 to 1 mg/kg/day. The three other most commonly used drugs were azathioprine (1 to 2.7 mg/kg/day), cyclosporine (3 to 8 mg/kg/day), and cylcophosphamide (1.1 to 3.3 mg/kg/day or 50 mg/m2/day for four days, or an initial dose of 200 mg/m2 followed by 50 mg/m2/day for three days).

Take-home message

There is a paucity of high-quality evidence available to make a general recommendation as to the "ideal" treatment regimen for dogs with IMHA. The authors note that this is likely due to the low incidence of the disease overall as well as difficulty in recruiting large numbers of cases for prospective trials.

Swann JW, Skelly BJ. Systematic review of evidence relating to the treatment of immune-mediated hemolytic anemia in dogs. J Vet Intern Med 2013;27(1):1-9.

Link to abstract: http://onlinelibrary.wiley.com/doi/10.1111/jvim.12028/abstract