Evaluation of the treatment of equine glandular gastric disease with either long-acting-injectable or oral omeprazole

Abstract

Background: Equine glandular gastric disease (EGGD) is common in domesticated horses and can be challenging to treat. Oral omeprazole (ORLO) is used widely but the clinical response is frequently poor. Objectives: To compare rates of EGGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO). Study design: Retrospective clinical study. Methods: The case records and gastroscopy images of horses presenting to masked for peer review over a 12-month period were reviewed, with images blindly assessed by one of the authors. Treatment responses to 4 mg/kg LAIO administered every 7 days for 2 and 4 weeks were compared with ORLO 4 mg/kg PO q24hrs for 4 weeks. Data were compared using a Mann-Whitney U test with post-hoc Dunn's test, Chi-squared test and a Fisher's exact test. Results: Thirty-three horses that received LAIO and 12 that received ORLO were identified. Nine horses in the LAIO had received other treatments previously. The groups were comparable in signalment and EGGD lesion severity. Long-acting injectable omeprazole was found to be non-inferior to ORLO. LAIO was associated with better healing rates than ORLO at 4 weeks (LAIO-80%; ORLO-42%; p = 0.02), and reduction in lesion severity at 2 and 4 weeks in the LAIO group but not in the ORLO group at 4 weeks. Eighteen percent of horses in the LAIO group and 50% in the ORLO group did not heal at 4 weeks. There was no association between rate of healing or improvement and resolution or improvement of clinical signs. Six localised and self-limiting injection site reactions were identified in 4 horses treated with LAIO (6.7%). Main limitations: Retrospective design, small numbers and the use of other treatments prior to use of LAIO. Conclusions: LAIO was found to be non-inferior to oral omeprazole for EGGD. Larger blinded randomised clinical trials are justified.