ABSTRACT
BACKGROUND: Guidelines regarding the impact and value of prophylaxis or maintenance therapy in equine gastric ulcer syndrome (EGUS) are not well-established or defined. The merits and the magnitude of effects of prophylaxis for spontaneous or recurrent squamous gastric ulceration in horses in training are uncertain. OBJECTIVES: To pool data from randomised controlled trials (RCTs) to eliminate reporting bias and evaluate the efficacy of prophylactic omeprazole in the prevention of EGUS in training horses, and secondarily to compare prophylactic dosages of omeprazole. STUDY DESIGN: Meta-analysis. METHODS: This meta-analysis was conducted according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic literature search identified RCTs comparing omeprazole prophylaxis with sham in prevention of EGUS. Data were analysed using the Mantel-Haenszel test method to calculate risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CIs). Primary outcome was efficacy of prophylaxis. Secondary outcome was endoscopic severity of ulceration. The influence of study characteristics on the outcomes was examined by subgroup analyses. RESULTS: In preventing gastric ulcer occurrence, omeprazole prophylaxis was superior to sham in training horses (7 trials, 566 horses, RR 0.28, 95% CI 0.18-0.43; 23.4% in omeprazole prophylaxis vs. 77.2% in sham; high quality evidence). Prevalence of ulceration was 75.3 and 87.2% in the sham arms of the 1 mg/kg and 2 mg/kg omeprazole groups, respectively. Severity scores were significantly lower for omeprazole vs. sham (mean difference [MD] -1.05; 95% CI -1.35 to -0.69). Subgroup analyses comparing prophylactic omeprazole dosages resulted in a mean difference of -0.94 and -1.60 for the 1 and 2 mg/kg groups, respectively. MAIN LIMITATIONS: Studies showed heterogeneity with regard to prophylactic dose. CONCLUSIONS: Omeprazole prophylaxis in active training horses significantly reduces gastric ulceration compared with no prophylaxis (sham) with the absolute effect of 566 fewer ulcers per 1000 horses treated.
