A comparison of three doses of omeprazole in the treatment of equine gastric ulcer syndrome: A blinded, randomised, dose-response clinical trial

Comparison of oral esomeprazole and oral omeprazole in the treatment of equine squamous gastric disease

BACKGROUND

Oral omeprazole is the accepted treatment for equine squamous gastric disease (ESGD); however, it is not universally effective. Esomeprazole results in more consistent and pronounced acid suppression in men and is more effective than omeprazole in the treatment of oesophageal and gastric disease. Pharmacodynamic and pilot clinical studies have indicated esomeprazole might also be more effective than omeprazole in horses.

OBJECTIVES

To compare the efficacy and safety of oral esomeprazole and omeprazole pastes in the treatment of ESGD and, where present, concurrent equine glandular gastric disease (EGGD).

STUDY DESIGN

Randomised, single-blinded controlled trial.

METHODS

Horses presenting with grade ≥2 ESGD lesions were randomly allocated to receive 4 mg/kg of either a buffered esomeprazole or omeprazole paste orally once daily for 28 days before gastroscopy being repeated within a further 3 days. Videos and images were anonymised and subsequently graded blind by one researcher. The severity of ESGD (and EGGD) lesions before and after treatment, and thereby treatment responses, were compared using univariable logistic regression.

RESULTS

A higher proportion of horses had ESGD healing in response to esomeprazole treatment (63/74, 85%) than with omeprazole treatment (43/73, 59%) (odds ratio [OR]: 4.00, 95% confidence interval [CI]: 1.81, 8.82, p = 0.001). In a subset of horses that had concurrent EGGD, a greater proportion of the horses treated with esomeprazole had lesions ≤grade 1 (esomeprazole 28/51, 55%; omeprazole 6/24, 25%; OR: 3.65, 95% CI: 1.25, 10.71, p = 0.02) Using grade 0 as the benchmark for EGGD healing, the difference remained significant (OR: 4.44, 95% CI: 1.33, 14.85, p = 0.02).

MAIN LIMITATIONS

It may not be possible to extrapolate these results to other populations with different signalment or management.

CONCLUSIONS

Oral-buffered esomeprazole was a more effective treatment for ESGD (and concurrent EGGD) than oral-buffered omeprazole.

Changes in saliva analytes in equine gastric ulcer syndrome (EGUS) after treatment: a pilot study

Equine gastric ulcer syndrome (EGUS) is a prevalent condition in horses, affecting up to 93% of racehorses. Comprising the equine squamous gastric disease (ESGD) and the equine glandular gastric disease (EGGD), EGUS poses significant health challenges. Saliva, a non-invasive and easily obtainable sample, is increasingly recognized for its potential as a source of biomarkers in horses. This study investigates changes in saliva analytes using automated assays before and after EGUS treatment, aiming to identify biomarkers indicative of treatment success or failure. A total of 28 horses diagnosed with EGUS were treatment with omeprazole for six weeks and further divided into successful (n = 15) or unsuccessful (n = 13) treatment group. Saliva samples were collected before and after treatment, and analytes related to enzymes, metabolites, proteins, redox biomarkers, and minerals were measured using an automated chemistry analyzer. Results revealed that horses with successful treatment, indicated by reduced EGGD and ESGD scores, showed significant increases in bicarbonate and urea, and decreases in adenosine deaminase (ADA), and creatine kinase (CK). Conversely, horses with non-successful treatment showed no significant changes in salivary analytes. These analytes have the advantages of an easy and fast measurement and the possibility of being applied in routine. Further studies with larger populations should be performed to establish the possible practical application of these analytes as biomarkers of treatment.

Should the use of omeprazole be allowed during equestrian competition?

BACKGROUND

Prioritising equine welfare, making evidenced-based policy, and consistent decision-making across sports are crucial to maintaining the social licence for equestrian sport. Regulations on the use of omeprazole during competition differ; all regulators argue that their rules prioritise welfare. This discrepancy is a matter of concern to the public and equestrian stakeholders.

OBJECTIVES

To apply Campbell's Ethical Framework for the use of Horses in Sport to the question: 'Should the use of omeprazole be allowed during equestrian competition?'

STUDY DESIGN

A desk-based ethico-legal study.

METHODS

Campbell's Ethical Framework for the Use of Horses in Sport was applied in a stepwise fashion: definition of the ethical question; analysis of the evidence base; consideration of stakeholders' interests; harm:benefit analysis; application of the three central tenets of the framework, and formulation of conclusions and recommendations.

RESULTS

Stakeholders in equine sports have a variety of (frequently conflicting) interests; all of them share an interest in optimising equine welfare. The incidence of EGUS in competition horses is high. Omeprazole is a cornerstone treatment. There are currently discrepancies in regulation about the use of omeprazole during competitions. Recent evidence suggests that withholding omeprazole treatment for two clear days before competition allows the recurrence of squamous EGUS, whereas withholding treatment on the day of competition only does not have that effect.

MAIN LIMITATIONS

The current state of scientific knowledge about the use of omeprazole in horses. The analysis did not consider possible health and thus welfare effects of the out-of-competition treatment with omeprazole.

CONCLUSIONS

Based on recent scientific evidence, if horses are being treated with omeprazole outside of competition then treatment on the day of competition should be permitted on welfare grounds. Revision of regulations around the use of omeprazole during competition by governing bodies is necessary to safeguard the ethical use of horses in sport.

Five- versus seven-day dosing intervals of extended-release injectable omeprazole in the treatment of equine squamous and glandular gastric disease

BACKGROUND

An extended-release injectable omeprazole formulation (ERIO) has become a popular treatment for equine squamous gastric disease (ESGD) and equine glandular gastric disease (EGGD) where it is available; however, published data are limited and optimal treatment regimens have not been determined.

OBJECTIVES

To compare effects of treatment on ESGD and EGGD when an ERIO formulation is administered at either 5- or 7-day intervals.

STUDY DESIGN

Retrospective clinical study.

METHODS

Case records and gastroscopy images of horses with ESGD or EGGD treated with ERIO were reviewed. Images were anonymised and graded by one researcher masked to treatment group. Treatment responses were compared between the two treatment schedules using univariable ordered logistic regression.

RESULTS

Forty-three horses were treated with ERIO at 5-day intervals and 39 horses at 7-day intervals. Signalment and presenting signs did not differ between groups. The proportions of horses with EGGD healing (to grade 0 or 1) in association with ERIO used at 5-day intervals (93%) were higher than associated with treatment at 7-day intervals (69%; odds ratio [OR]: 2.41, 95% CI: 1.23-4.74, p = 0.01). For ESGD, there was no significant difference in the proportion of horses healing in association with treatment at 5-day intervals (97%) compared with 7-day intervals (82%; OR: 2.75, 95% CI: 0.91-8.31, p = 0.07). Four of 328 injections were associated with an injection-site reaction (1%).

MAIN LIMITATIONS

Retrospective study design, lack of randomisation and limited case numbers.

CONCLUSIONS

The use of ERIO at 5-day intervals might be more appropriate than the 7-day interval that is used currently.

Heart rate variability during high-speed treadmill exercise and recovery in Thoroughbred racehorses presented for poor performance

BACKGROUND

Heart rate variability (HRV) analysis measures the inter-beat interval variation of successive cardiac cycles. Measurement of these indices has been used to assess cardiac autonomic modulation and for arrhythmia identification in exercising horses.

OBJECTIVES

To report HRV indices during submaximal exercise, strenuous exercise and recovery, and explore relationships with clinical conditions (arrhythmias, lameness, equine gastric ulcer syndrome [EGUS], lower airway inflammation and upper respiratory tract obstructions [URTOs]) in Thoroughbred racehorses.

STUDY DESIGN

Retrospective, observational cross-sectional study.

METHODS

One hundred and eighty Thoroughbred horses underwent a treadmill exercise test with simultaneous electrocardiographic recording. Time-domain HRV indices (standard deviation of the R-R interval [SDRR]; root mean square of successive differences [RMSSD]) were derived for submaximal and strenuous exercise and recovery segments. Clinical conditions (arrhythmia [during each phase of exercise], lameness, EGUS, lower airway inflammation and URTO) were assigned to binary categories for statistical analysis. Relationships between selected HRV indices and the clinical conditions were explored using linear regression models.

RESULTS

During submaximal exercise, lameness was associated with decreased logRMSSD (B = -0.19 95% confidence interval [CI] -0.31 to -0.06, p = 0.006) and arrhythmia was associated with increased logRMSSD (B = 0.31 95% CI 0.01-0.608, p = 0.04). During strenuous exercise, arrhythmia was associated with increased HRV indices (logSDRR B = 0.51 95% CI 0.40-0.62, p < 0.001; RMSSD B = 0.60 95% CI 0.49-0.72, p < 0.001). During recovery, arrhythmia was associated with increased HRV indices (logSDRR B = 0.51 95% CI 0.40-0.62, p < 0.001, logRMSSD B = 0.60 95% CI 0.49-0.72, p < 0.001).

MAIN LIMITATIONS

The main limitations of this retrospective study were that not every horse had the full range of clinical testing, therefore some horses may have had undetected abnormalities.

CONCLUSIONS

The presence of arrhythmia increased HRV in both phases of exercise and recovery. Lameness decreased HRV during submaximal exercise.

Effect of diet composition on glandular gastric disease in horses

BACKGROUND

Nutritional factors are suggested to influence the incidence and severity of glandular gastric disease (GGD) in horses.

OBJECTIVES

To retrospectively assess whether dietary fermentable carbohydrates increase the severity of GGD and to prospectively evaluate whether the partial substitution of concentrates by dehydrated alfalfa would decrease GGD severity scores.

ANIMALS

In total, 82 trotters from 4 training centers exercised ≥5 days/week.

METHODS

Multicenter retrospective observational study, and prospective 2-arm randomized trial. Glandular mucosae were observed by gastroscopy and scored (0-4 severity scale) at day 0 (D0). Biochemical composition of the diet fed was compared between ulcerated and nonulcerated groups. After D0, horses either received the same diet (control, n = 41) or pelleted dehydrated alfalfa substituting 50% concentrates (alfalfa, n = 41). Glandular scores were recorded in both groups after 21 (D21) and 42 days (D42). The first end point was a successful outcome, defined as a horse with a glandular score of 2 to 4 on D0, decreasing to a score of 0 to 1 on days 21 or 42.

RESULTS

Horses scored 0 to 1 at D0 ingested more (P = .01) soluble sugars from concentrates than those scored 2 to 4 before D0 (77.5 g/kg BW; 95% confidence interval [CI]: 71.1-84.0, vs 59.1 g/kg BW; 95% CI: 48.0-70.3), whereas starch intake did not differ between groups (P = .24). Among horses scored 2 to 4 at D0, fewer were scored 2 to 4 in the alfalfa group (1 out of 6) compared with the control group (6 out of 6) at D42 (P = .02). Clinical success was 47.7 times more likely in horses fed alfalfa compared with horses in the control group (95% CI: 1.6-1422.8).

CONCLUSION AND CLINICAL IMPORTANCE

Relationships were found between diet composition and integrity of the glandular mucosa. Feeding pelleted dehydrated alfalfa could help to reduce the incidence and severity of GGD.

A Comparison of the Efficacy of Two Omeprazole Formulations in the Treatment of Equine Gastric Ulcer Syndrome in Racehorses: A Blinded, Randomized Clinical Trial

Equine gastric ulcer syndrome (EGUS) is the most common disease of the stomach in horses and treatment is based on the oral administration of omeprazole for at least 28 days. Aim of this study was to compare the efficacy of two formulations of oral omeprazole-powder paste and gastro-enteric resistant granules-in the treatment of naturally occurring gastric ulcers in racehorses. Thirty-two adult racehorses, aged between 2 and 10 years old, with clinical signs of EGUS were included in this blinded, randomized clinical trial. Two gastroscopies were performed to evaluate gastric lesions in the squamous or glandular mucosa before and after 28 days of treatment. After the first gastroscopy, 2/32 horses were excluded because affected by equine squamous gastric disease (ESGD) 1/4. The remaining horses were divided into 4 groups, and were treated with 2 formulations of omeprazole (gastroenteric resistant granules, group 1, or powder paste, group 3) or with 2 placebo formulations (granules, group 2, or paste, group 4). Treatments were performed in the placebo horses affected by ESGD or equine glandular gastric disease after the T28 gastroscopy control. No differences were found between groups at T0. Differences were found between T0 vs. T28 for granular (P = .002) and powder paste (P = .01) formulations. No differences were detected between the two groups receiving omeprazole formulations at T28 (0.34) and between T0 vs. T28 for either of the groups receiving placebo treatments. For all the variables, the size of the effect was greater than 0.5, proving that the treatments had a considerable effect. Gastro-enteric resistant granules and powder paste omeprazole showed similar efficacy in the treatment of ESGD. The glandular mucosa responded poorly to treatment with omeprazole.

The Impact of Two Recommended Withholding Periods for Omeprazole and the Use of a Nutraceutical Supplement on Recurrence of Equine Gastric Ulcer Syndrome in Thoroughbred Racehorses

The impact of recommended withholding periods (RWPs) for omeprazole on the recurrence of Equine Gastric Ulcer Syndrome (EGUS) is unknown. The study was designed to compare the effect of two RWPs on EGUS recurrence post-omeprazole treatment and to determine if a nutraceutical supplement would reduce EGUS recurrence when administrated during an RWP. The study was a blinded, randomized clinical trial. Part 1: Horses were allocated to an RWP0 or RWP2 and crossed over after 4-weeks. Horses received oral omeprazole once daily, except during the RWPs at the end of the treatment periods. Part 2: Horses received omeprazole for 21 days prior to an RWP2 during which they received a nutraceutical supplement. Gastroscopy was performed on Day 0 and pre- and post- RWP. Part 1: More horses were affected by Equine Squamous Gastric Disease (ESGD) after the '2-clear-days' RWP than the 'not on race-day' RWP (p = 0.012). The prevalence of ESGD post-RWP for '2-clear-days' did not differ from day 0 (p = 0.478). Part 2: The prevalence of ESGD post-RWP was lower than on Day 0 (p = 0.046). A difference in recurrence of ESGD was present between the two common RWPs. The implications of this on the welfare of Thoroughbred racehorses warrant further discussion.

Horse Grimace Scale Does Not Detect Pain in Horses with Equine Gastric Ulcer Syndrome

Equine gastric ulcer syndrome (EGUS) is a highly prevalent and presumptively painful condition, although the amount of pain horses might experience is currently unknown. The aims of this study were to determine if the Horse Grimace Scale (HGS) could identify pain behaviours in horses with and without EGUS and if severity would be positively associated with the HGS score. Horse grimace scale scores were assessed blindly using facial photographs by seven observers and involved evaluation of 6 facial action units as 0 (not present), 1 (moderately present) and 2 (obviously present). Lameness examination, serum amyloid A (SAA) measurement and gastroscopy evaluation were performed on all horses. Horses (n = 61) were divided into two and three groups based on the presence (yes, no) and severity (none, mild, moderate-severe) of EGUS, respectively. Presence of lameness and elevated SAA (≥50 µg/mL) were used as exclusion criteria. Inter-observer reliability was analyzed by intra-class correlation coefficients (ICC). HGS scores between groups were compared using Welch's and Brown Forsythe tests (p < 0.05). Overall, HGS ICC was "excellent" (0.75). No significant differences (p = 0.566) were observed in HGS scores between horses with and without gastric lesions (mean, 95% CI; 3.36, 2.76-3.95 and 3, 1.79-4.20, respectively). HGS was not influenced by the presence or severity of EGUS in this current study. Further studies investigating the use of different pain scales in horses with EGUS are needed.

Current Topics in Medical Colic

The list of medical causes of acute or chronic colic in horses is extensive. The purpose of this article is to review 4 medical causes of equine colic with a focus on newer trends in treatment. The 4 topics selected include gastric impaction, gastric glandular disease, colon displacement, and inflammatory bowel disease.

Does lesion type or severity predict outcome of therapy for horses with equine glandular gastric disease? - A retrospective study

BACKGROUND

Equine glandular gastric disease (EGGD) is a common condition of the horse. Misoprostol is reported to be superior to oral omeprazole and sucralfate for treatment. Long-acting intramuscular injectable omeprazole (LAIOMEP) is a novel treatment shown to be effective in a small population.

OBJECTIVES

This study aimed to determine LAIOMEP efficacy compared to misoprostol and oral omeprazole and identify characteristics that predict treatment outcome.

METHODS

All horses that underwent gastroscopy between 2012 and 2019 were reviewed. Lesions were characterised by 4 blinded observers, all of whom are diplomates in equine internal medicine, using established descriptors from the ECEIM consensus statement and subjective severity. Treatment outcome was ranked as worsened, improved or healed. Consensus lesion type, lesion severity and treatment choice were compared to outcome and data screened using univariate analysis (chi-squared) to determine whether each predicted outcome. Lesion types where univariate analysis predicted a trend (p<0.2) were included in a multiple-regression analysis to identify predictors of outcome irrespective of treatment.

RESULTS

Only severity significantly predicted final outcome (p = 0.025) with severe lesions being more likely to improve. Treatment choice did not significantly predict outcome. Overall healing rate was 29% (24 horses), and 43% (44 horses) improved. Treatment healing rates were 23% (10), 12% (7) and 27% (7) for LAIOMEP, misoprostol and oral omeprazole, respectively, with improvement in 69% (14), 76% (21) and 61% (9). 64% of the latter group received sucralfate. Worsening occurred in 7% (6). Treatment length varied with a median of 4 weeks (range 4-20 weeks).

CONCLUSIONS

This study showed poorer therapy outcome compared to previous studies. The only initial lesion descriptor to predict outcome was severity and treatment choice did not affect outcome.

Assessment of agreement using the equine glandular gastric disease grading system in 84 cases

Introduction

Equine glandular gastric disease (EGGD) is a common condition causing signs of gastric pain although lesions are highly variable in their appearance. The only definitive method to diagnose EGGD ante‐mortem is gastroscopy. The current recommended method for describing these lesions is the European College of Equine Internal Medicine (ECEIM) guidelines; however, repeatability between users is variable. This study aimed to validate the reliability of lesion descriptions using ECEIM consensus guidelines, using four blinded equine internal medicine diplomates.

Methods

Ninety‐two horses with EGGD with pre‐ and post‐treatment gastroscopy images were identified using the electronic record at a UK equine hospital between 2012 and 2019. Eight horses were excluded due to non‐diagnostic images. Four blinded observers used the recommended grading system to describe images and outcomes. Intraclass correlation coefficients and Krippendorff's alpha were used to determine reliability and agreement, respectively.

Results

Intraclass correlation coefficient for severity was 0.782 (95% confidence interval [CI] 0.722–0.832), for distribution was 0.671 (95% CI 0.540–0.763), for the descriptor raised was 0.635 (95% CI 0.479–0.741), fibrinosuppurative was 0.745 (95% CI 0.651–0.812), haemorrhagic was 0.648 (95% CI 0.513–0.744), hyperaemic was 0.389 (95% CI 0.232–0.522) and for outcome was 0.677 (95% CI 0.559–0.770). Krippendorff's alpha for severity was 0.466 (95% CI 0.466–0.418), for distribution was 0.304 (95% CI 0.234–0.374), for the descriptor raised was 0.268 (95% CI 0.207–0.329), fibrinosuppurative was 0.406 (95% CI 0.347–0.463), haemorrhagic was 0.287 (95% CI 0.229–0.344), hyperaemic was 0.112 (95% CI 0.034–0.188) and for outcome was 0.315 (95% CI 0.218–0.408).

There was moderate reliability determined between observers using intra‐class correlation coefficients and unacceptable agreement determined between observers using Krippendorff's alpha.

Discussion

These results suggest that the current grading system is not comparable between observers, indicating the need to review the grading system or define more robust criteria.

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

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.

Equine glandular gastric disease (EGGD) is common in domesticated horses and can be challenging to treat. 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.

Phytotherapy compared to omeprazol therapy in equine gastric ulcers

The aim of this study was to offer an alternative therapy for gastric ulcers in horses as the interest in natural products is growing not only among practicioners but also horse owners. We compared the treatment of equine gastric squamous mucosa ulcers by omeprazol and by nutraceutical herbal mixture PREVUL (Dzsar Ltd., FitoCavallo, Hungary). A total of 36 horses, 18 geldings, 15 non-pregnant mares and 3 stallions were diagnosed with Equine Squamous Gastric Disease (ESGD) by gastroscopy. Horses were randomly divided into three groups. The first group was treated with 4 mg/kg omeprazole paste (Peptizole, Norbrook, United Kingdom) per os once daily on empty stomach for 28 days. The second group received 20 g of pulverized herbal mixture PREVUL twice daily in cracked oats for 28 days. The third experimental group received 2 mg/kg omeprazole per os once daily on empty stomach followed by 15 g of PREVUL mixed with cracked oats twice daily for 28 days. Ten healthy horses were used as control to evaluate the palatability and voluntary intake of PREVUL. Control gastroscopy was performed afted 30 days. The use of PREVUL alone P < 0.05 or in combination with omeprazole paste P < 0.01 appears to improve the healing of gastric ulcers in horses.

Prevalence and treatment of gastric ulcers in Thoroughbred racehorses of Korea

Background

Gastric ulcer is one of the prevalent diseases in racehorses. However, it has not been recognized as important in Korea, and drugs used to treat gastric ulcers are included in the doping test list, so they are not allowed to be administered to racehorses in training.

Objectives

This study was performed 1) to investigate the prevalence and the severity of gastric ulcers in Thoroughbred racehorses in Korea, 2) to confirm the therapeutic effect of ranitidine and omeprazole, and 3) to compare the efficacy between ranitidine and omeprazole.

Methods

Forty-nine horses were randomly recruited, and gastroscopy was performed within two days after racing. Twelve horses with a sum grade of five or higher were randomly assigned to two treatment groups. Seven horses were administered ranitidine, and five horses were administered omeprazole. Follow-up gastroscopy was scheduled within one to five days after finishing the treatment.

Results

The prevalence of gastric ulcer in Korean Thoroughbred racehorses after racing was 100%, and the grade was more severe in the non-glandular region than in the pyloric region. There was no correlation between the severity of gastric ulcer in the two regions. Omeprazole had a greater therapeutic effect than ranitidine.

Conclusions

This study shows the importance of recognizing gastric ulcers as an important factor, and omeprazole as a possible treatment option in Korea, as it has been removed from the list of prohibited substances for racehorses. Thus, the use of omeprazole is currently recommended until one day before the race.

Equine Squamous Gastric Disease: Prevalence, Impact and Management

This narrative review explores the etiopathogenesis, clinical signs, diagnosis and treatment of ESGD (equine squamous gastric disease) and discusses the impact of this commonly encountered condition on the equine industry. ESGD refers specifically to peptic injury of the squamous mucosa of the stomach. Prevalence is highest in performance horses, but the disease has been documented across many breeds and ages, including in feral horses and foals. The pathogenesis of ESGD is well understood. Intensive management and exercise are important factors that contribute to a disruption of the normal stratification of gastric pH. This results in exposure of the vulnerable squamous mucosa to acid, leading to ulceration. Clinical signs are variable and there is little evidence to support a direct association between reported signs and the presence or absence of lesions seen on gastroscopy. Management is aimed at acid suppression and mitigation of known risk factors.

Effect of omeprazole and sucralfate on gastrointestinal injury in a fasting/NSAID model

BACKGROUND

Equine gastric ulcer syndrome (EGUS) is a common and significant cause of morbidity in horses, with a range of clinical signs, including inappetence, colic and poor performance. Hospitalised horses are exposed to factors that may induce EGUS, including fasting and nonsteroidal anti-inflammatory drug (NSAID) administration, and may be at risk for development of squamous (ESGD) and glandular gastric disease (EGGD). Prophylactic anti-ulcer medication is often prescribed for these patients, but drug selection is complicated by different aetiology and response to treatment of ESGD and EGGD.

OBJECTIVES

To establish the efficacy of sucralfate or omeprazole used prophylactically in horses exposed to a combined feed-fast and NSAID administration EGUS induction protocol. We hypothesised that these drugs would be equally effective for prevention of gastric lesions in the experimental cohort.

STUDY DESIGN

Randomised crossover experimental design.

METHODS

Horses (n = 14) received either omeprazole (1 mg/kg PO q24h) or sucralfate (20 mg/kg PO q8h) while undergoing the feed-fast/NSAID protocol, allowed an 8-week washout period, and then administered the alternate treatment. Serial gastroscopy, ultrasound and haematology documented treatment effects.

RESULTS

ESGD and EGGD score increased over time under both treatments. There was a significant effect of treatment on EGGD scores (P < .001), with post-treatment EGGD scores higher for horses receiving sucralfate (median 3; IQR 2.25,3) than omeprazole (1; 1,1). The effect of treatment on ESGD scores just achieved significance (P = .05), with post-treatment ESGD scores higher for sucralfate (4; 3,4) than omeprazole (2; 2,3).

MAIN LIMITATIONS

This study was performed in healthy horses, and response to treatment may differ in horses with clinical illness. Additional investigation in a larger population may be required to detect significant differences in other clinical parameters.

CONCLUSIONS

Omeprazole was superior to sucralfate for mitigating gastric lesion severity in healthy horses exposed to a feed-fast/NSAID model.

Gastric microbiome in horses with and without equine glandular gastric disease

Background

The role of the gastric microbiome in development or persistence of equine glandular gastric disease (EGGD) remains to be investigated.

Hypothesis/Objectives

The objective was to characterize the glandular mucosal and gastric fluid microbiomes of horses with and without EGGD. It was hypothesized that differences in the mucosal microbiome are associated with EGGD.

Animals

Twenty‐four horses were enrolled.

Methods

Gastroscopy was performed and EGGD scores recorded (score 0, n = 6; score 1, n = 8; score ≥2, n = 10). Gastric fluid and pinch biopsies of healthy glandular mucosa and EGGD lesions were collected via gastroscope. 16S rRNA amplicon sequencing of the gastric fluid and glandular mucosal biopsies was performed. Relationships between gastric fluid and mucosal microbial community composition were evaluated among EGGD score groups (EGGD 0‐BX, EGGD 1‐BX, EGGD ≥2‐BX) and among endoscopic appearances: controls from horses without EGGD and normal areas, hyperemic areas, and lesions from horses with EGGD.

Results

Microbial community structure of mucosal biopsies differed among EGGD score groups (Jaccard similarity index; P = .009). Principal coordinate analysis showed separate clusters for EGGD 0‐BX and EGGD ≥2‐BX.

Conclusions and Clinical Importance

A modest difference was detected in the community structure of the gastric glandular mucosal microbiome in association with EGGD score.

Effect of a novel rice fermented extract on gastric ulcers in horses

Gastric ulcers cause appetite loss, poor body condition, and colic in horses. This study investigated the protective effect of a rice fermented extract on the gastric mucosa in 17 healthy Thoroughbreds. For one month, horses in the rice fermented extract (nine horses) and control (eight horses) groups were orally administered a rice fermented extract (100%; 0.2 ml/kg, SID) and tap water (0.2 ml/kg), respectively. Gastric endoscopic images were obtained before and one month after rice fermented extract administration. The gastric ulcer score was lower after administration (median, 1; maximum, 2; minimum, 1) than before administration (median, 4; maximum, 4; minimum, 3) in the rice fermented extract group (P<0.05). In conclusion, the administration of a rice fermented extract for one month improves gastric mucosal lesions in Thoroughbreds with gastric ulcers.

Pharmacokinetic and pharmacodynamic effects of 2 registered omeprazole preparations and varying dose rates in horses

Background

Omeprazole preparations vary in bioavailability in horses.

Hypothesis/Objectives

To characterize the pharmacokinetics and pharmacodynamics of an existing enteric‐coated oral omeprazole paste (REF) and a novel, in‐feed, enteric‐coated dry granule preparation (NOV).

Animals

Twelve Standardbred/Thoroughbred mares free from clinical disease.

Methods

A prospective, blinded randomized interventional study was trial, conducted in 3 parts: (a) bioavailability study, (b) dose titration study, and (c) comparative clinical pharmacodynamic study, each using a blocked crossover design.

Results

Consistent with the larger dose administered, Cmax (median, 1032 ng/mL; range, 576‐1766) and AUC0‐24 (median, 63.9 μg/mL*min; range, 42.4‐152.4) were greater after single oral administration of NOV than REF (282.7 ng/mL; range, 94.8‐390.2, and 319 23.8 μg/mL*min; range, 8.2‐42.3, respectively; both P = .004). No differences were observed between products for absolute oral bioavailability (NOV 55% range, 15‐88; REF 17% range, 10‐77; P = .25). Treatment with both preparations was associated with reduced gastric squamous ulcer scores and increased pH of gastric fluid. Bioequivalence was demonstrated for pharmacodynamic measures with the exception of % time pH <4, despite differences in dose rate and subsequent plasma omeprazole concentrations.

Conclusions and Clinical Importance

The findings of this study indicate that the NOV product would be a suitable alternative to the reference product, and confirm that plasma concentrations of omeprazole and omeprazole dose do not predict drug pharmacodynamics in horses.

Interobserver and intraobserver reliability for 2 grading systems for gastric ulcer syndrome in horses

Background

Grading of equine gastric ulcer syndrome (EGUS) is undertaken in clinical and research settings, but the reliability of EGUS grading systems is poorly understood.

Hypothesis/Objectives

Investigate interobserver and intraobserver reliability of an established ordinal grading system and a novel visual analog scale (VAS), and assess the influence of observer experience.

Animals

Sixty deidentified gastroscopy videos.

Methods

Six observers (3 specialists and 3 residents) graded videos using the EGUS Council (EGUC) system and VAS. Observers graded the videos three 3 for each system, using a cross‐over design with at least 1 week between each phase. The order of videos was randomized for each phase.

Methods

Interobserver and intraobserver reliability were estimated using Gwet's agreement coefficient with ordinal weights applied (AC2) for the EGUC system and the intraclass correlation coefficient (ICC) for the VAS.

Results

Using the EGUC system, interobserver reliability was substantial for squamous (AC2 = 0.69; 95% confidence interval [CI], 0.57‐0.80) and glandular mucosa (AC2 = 0.72; 95% CI, 0.70‐0.75), and intraobserver reliability was substantial for squamous (AC2 = 0.80; 95% CI, 0.71‐0.90) and glandular mucosa (AC2 = 0.80; 95% CI, 0.74‐0.86). Interobserver reliability using the VAS was moderate for squamous (ICC = 0.64; 95% CI, 0.31‐0.96) and poor for glandular mucosa (ICC = 0.35; 95% CI, 0.06‐0.64), and intraobserver reliability was moderate for squamous (ICC = 0.74; 95% CI, 0.62‐0.86) and glandular mucosa (ICC = 0.56; 95% CI, 0.39‐0.72).

Conclusions and Clinical Importance

The EGUC system had acceptable intraobserver and interobserver reliability and performed well regardless of observer experience. Familiarity and observer experience improved reliability of the VAS.

A study investigating the treatment of equine squamous gastric disease with long-acting injectable or oral omeprazole

BACKGROUND

Equine squamous gastric disease (ESGD) is a highly prevalent disease in horses, particularly in elite athletes. Some horses respond slowly, or fail to respond, to the licensed treatment, oral omeprazole (ORLO).

OBJECTIVES

To compare rates of ESGD 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 Rainbow Equine Hospital over a 12-month period were reviewed, with images being reviewed blind by one of the authors (David Rendle). Treatment responses were compared between horses that received 2 or 4 injections of 4 mg/kg LAIO at weekly intervals, and horses that received ORLO at 4 mg/kg PO SID for 4 weeks. Data were compared using a Mann-Whitney test with post hoc Dunn's test, chi-squared test or Fisher's exact test.

RESULTS

Fifty-six horses met the inclusion criteria: 29 received LAIO and 27 received ORLO. Treatment groups were comparable in terms of signalment and ESGD lesions. There was a difference in rate of healing when LAIO and ORLO treatment groups were compared at 28 days (LAIO-97%; ORLO-67%; p = .005; OR = 14(1.8-158)), but no difference between LAIO at 14 days and ORLO at 28 days (LAIO-86%; ORLO-67%; p = .12; OR = 3.1 (0.9-10)). Five localised and self-limiting injection site reactions were identified in 3 horses out of 98 injections (5.1%).

MAIN LIMITATIONS

The study was limited by its retrospective nature, absence of randomisation and limited numbers.

CONCLUSIONS

Four weeks of treatment with LAIO resulted in better rates of ESGD healing than 4 weeks of ORLO. Larger more robust studies of LAIO are warranted.

Effects of astragaloside IV on the pharmacokinetics of omeprazole in rats

Context: Omeprazole and astragaloside IV (AS-IV) are widely used for the treatment of gastric ulcers in China clinics. Objective: This study investigates the effects of AS-IV on the pharmacokinetics of omeprazole in rats. Materials and methods: The pharmacokinetics of orally administered omeprazole (2 mg/kg), with or without AS-IV (100 mg/kg/day for 7 days) pretreatment, were investigated in male Sprague-Dawley rats (two groups of six animals each) using LC-MS/MS. A Caco-2 cell transwell model and rat liver microsome incubation systems were also used to support the in vivo pharmacokinetic data and investigate its potential mechanism. Results: The results indicated that co-administration of AS-IV could decrease the systemic exposure of omeprazole significantly (p < 0.05), including AUC_0-t (717.20 ± 177.63 vs. 1166.25 ± 186.65 ng h/mL) and C_max (272.35 ± 25.81 vs. 366.34 ± 32.57 ng/mL). The t_1/2 of omeprazole also decreased significantly (1.78 ± 0.15 vs. 2.23 ± 0.27 h, p < 0.05). The efflux ratio of omeprazole across the Caco-2 cell transwell model increased significantly from 1.73 to 2.67 (p < 0.05), and the metabolic stability of omeprazole was decreased from 42.6 ± 7.8 to 26.2 ± 5.1 min with the pretreatment of AS-IV (p < 0.05). Discussion and conclusions: AS-IV could decrease the systemic exposure of omeprazole in rats when AS-IV and omeprazole were co-administered, and it might exert these effects through decreasing the absorption of omeprazole by inducing P-gp, or through accelerating the metabolism of omeprazole in rat liver by inducing the activity of CYP3A4.

Chronic severe pyloric lesions in horses: 47 cases

BACKGROUND

The clinical findings and outcome associated with chronic severe equine pyloric lesions have not been well described previously.

OBJECTIVES

To describe the history, clinical signs, endoscopic and ultrasound results, laboratory data, treatment, pathological findings and survival of horses with chronic severe pyloric lesions.

STUDY DESIGN

Retrospective case series.

METHODS

Medical records from horses treated at clinics in Czech Republic and Germany in which chronic severe pyloric lesions were confirmed endoscopically and/or on post-mortem examination were reviewed.

RESULTS

Forty-seven horses were identified, median age 3 years (range 0.8-16 years). There were 3 geldings, 23 mares and 19 stallions and the majority were Warmbloods (60%). The most common presenting signs were poor body condition (40; 87%), slow eating (39; 83%), recurrent colic (35; 74%) and selective appetite (30; 64%). The most consistent laboratory abnormality was hypoalbuminaemia (10; 36%). Slow gastric emptying was confirmed in 29 individuals during gastroscopy and/or ultrasonography. Endoscopy revealed distal oesophagitis in 9 of 47 horses, and severe equine squamous gastric disease in all cases. Pyloric lesions were depressed, flat or raised fibrinosuppurative pyloric ulcers and were seen in 45 (2 pylori were not seen endoscopically). Thirty-two cases were treated, with 28 responding well initially. All treated cases received anti-ulcer medication and four underwent gastrojejunostomy. Clinical signs recurred after medical treatment in at least 11 cases. Only 18 of 44 cases (41%) survived long term (3 were lost to follow-up). Horses diagnosed at 3 years of age or younger were significantly less likely to survive more than 6 months than older horses (27.8% vs. 72.2%, P<0.001).

MAIN LIMITATIONS

The study is retrospective, some records were incomplete and case identification was subjective.

CONCLUSIONS

Chronic severe pyloric lesions can be associated with delayed gastric emptying identified with ultrasonography and/or endoscopy. The prognosis is poor in young horses.

Equine glandular gastric disease: prevalence, impact and management strategies

Equine glandular gastric disease (EGGD) is an increasingly recognized disease of the glandular mucosa of the equine stomach. Diagnosis is confirmed by gastric endoscopy and scored based upon one of several different endoscopic scoring systems. Prevalence appears to be variable, depending upon breed and discipline. Primary identified risk factors include exercise frequency, and stress; therefore, management strategies are focused on reducing exercise and stress. Limiting grain intake and increasing pasture turnout may also be helpful preventative measures. Pharmacologic treatment consists primarily of an approved omeprazole product with or without misoprostol or sucralfate. Further research into the pathophysiology of EGGD may allow for identification of other targeted treatments.

Effect of Changing Diet on Gastric Ulceration in Exercising Horses and Ponies After Cessation of Omeprazole Treatment

Diet is an accepted risk factor for equine squamous gastric disease (ESGD), but there is little published evidence for the benefit of dietary change (DC). This study evaluated the effect of DC with or without initial omeprazole medication. Twelve pairs of exercising horses with ESGD Grade 2/4 (EM) and 17 pairs with ESGD Grade ≥3/4 (ES), were monitored. Paired horses had similar management, feeding times, workloads, and initially feed or forage. One of each pair was randomly assigned, postgastroscopy (Scope1), to a specified restricted starch ration; the other remained on their original diet. Omeprazole (4 mg/kg per os SID) was given to all ES pairs for 4 weeks. Gastroscopies were scored, without dietary knowledge, after 4 and 10 weeks (Scopes 2 and 3). Workloads remained similar throughout. McNemar's tests identified any changes in ESGD grade. Within the EM group, DC had no additional effect. For the ES group remaining on their original diet, there was significant improvement in ESGD grade from Scopes 1 to 2 (P < .001) but a worsening between Scopes 2 and 3 (P = .005), with Scope 3 being no different from Scope 1 (P = .08) reflecting no apparent long-term medication benefit. For the DC group, there was significant improvement in ESGD grade from Scopes 1 to 2 (P < .001) and between Scopes 1 and 3 (P = .003); In addition, there was no significant difference between Scopes 2 and 3 (P = .32). Although limited by the small number of pairs evaluated, this study provides evidence that appropriate DCs can be a beneficial management strategy for ESGD.

Management factors and clinical implications of glandular and squamous gastric disease in horses

BACKGROUND

To date, risk factors for equine glandular gastric disease (EGGD) have not been described in Thoroughbred racehorses.

OBJECTIVES

To determine management factors associated with EGGD, identify clinical signs in affected horses, and compare these to equine squamous gastric disease (ESGD).

ANIMALS

The study was carried out on 109 Thoroughbred racehorses from 8 training yards (3 in the United Kingdom and 5 in Australia).

METHODS

Gastroscopic examination alongside a questionnaire regarding management, feeding, exercise, and health.

RESULTS

Management factors and clinical signs were different for EGGD versus ESGD. Exercising ≥5 days per week was associated with a 10.4 times (95% CI [confidence interval]: 1.34-26.9) increased risk of EGGD. Horses racing below expectation were 3.7 times (95% CI: 1.1-16.7) more likely to have EGGD. Trainer was also identified as a risk factor for EGGD. Time in work ≤6 weeks was associated with a decreased risk of ESGD (odds ratio [OR] 0.3; 95% CI: 0.1-0.99). Horses aggressive to humans were less likely to have ESGD (OR 0.12; 95% CI: 0.03-0.54). Horses with stereotypies were more likely to have ESGD (OR 5.0; 95% CI: 1.6-15.9).

CONCLUSIONS AND CLINICAL IMPORTANCE

The findings of our study further support the notion that EGGD should be considered as a distinct disease entity to ESGD. Exercising ≤4 days per week could reduce the risk of EGGD. Horses with EGGD are more likely to perform below expectation and, as such, EGGD might be performance limiting in some affected individuals. Stress minimization could reduce the risk of EGGD.

Risk Factors for Equine Gastric Glandular Disease: A Case-Control Study in a Finnish Referral Hospital Population

Background

Equine gastric glandular disease (EGGD) is a term used to classify erosive and ulcerative diseases of the glandular mucosa of the equine stomach. Epidemiologic studies of risk factors for EGGD have not been reported.

Objective

To determine risk factors for EGGD.

Animals

Cases (n = 83) had endoscopic evidence of EGGD; controls (n = 34) included healthy horses and horses with equine squamous gastric disease (ESGD) without EGGD.

Methods

Retrospective case‐control study. The data were analyzed by multivariable logistic regression modeling. Analysis was performed on the full dataset. An additional analysis compared horses with glandular lesions (n = 43) against healthy horses (n = 22).

Results

On first analysis, Warmblood breed (OR = 13.9, 95% CI 2.2–90.9, P = .005) and an increasing number of caretakers (OR = 7.3, 95% CI 0.98–55.6, P = .053) were associated with an increased risk of EGGD. On analysis of the subset of data, Warmblood breed (OR = 28.6, 95% CI 2.96–250.0, P = .004) and increasing number of riders (OR = 12.99, 95% CI 0.94–166.7, P = .056) were risk factors. The presence of sand in the colon appeared to have a protective effect against EGGD (OR = 0.195, 95% CI 0.04–1.0, P = .051 for sand versus not having sand).

Conclusions and clinical importance

This study suggests that Warmbloods are predisposed to EGGD and multiple handlers/riders might increase the risk of EGGD. Identification of risk factors allows speculation on potential pathophysiological mechanisms of EGGD.

Therapeutics for Equine Gastric Ulcer Syndrome

Equine gastric ulcer syndrome (EGUS) is an umbrella term used to describe ulcers in the nonglandular squamous and glandular mucosa, terminal esophagus, and proximal duodenum. Gastric ulcers in the squamous and glandular regions occur more often than esophageal or duodenal ulcers and likely have a different pathogenesis. At present, omeprazole is accepted globally as the best pharmacologic therapy for both regions of the stomach; however, the addition of coating agents and synthetic prostaglandins could add to its effectiveness in treatment of EGUS. Dietary and environmental management are necessary for prevention of recurrence.

Diagnostic accuracy of blood sucrose as a screening test for equine gastric ulcer syndrome (EGUS) in adult horses

Background

Equine gastric ulcer syndrome (EGUS) is common in adult horses, particularly those involved in performance disciplines. Currently, detection of EGUS by gastroscopy is the only reliable ante mortem method for definitive diagnosis; however it is unsuitable as a screening test because it is expensive, time consuming, and is not readily available to most veterinarians. Sucrose permeability testing represents a simple, economical alternative to gastroscopy for screening purposes, and the feasibility of this approach in the horse has been previously reported. The aim of this study was to determine the diagnostic accuracy of blood sucrose as a screening test for EGUS in a large group of adult horses with and without naturally occurring gastric disease.

Results

One hundred and one adult horses with or without naturally occurring gastric ulceration were studied. The diagnostic accuracy of blood sucrose for diagnosis of gastric lesions (GL), glandular lesions (GDL), squamous lesions (SQL), and clinically significant lesions (CSL) at 45 and 90 min after administration of 1 g/kg of sucrose via nasogastric intubation was assessed using receiver operator characteristics (ROC) curves and calculating the area under the curve (AUC). For each lesion type, sucrose concentration in blood was compared to gastroscopy, as the gold standard, and sensitivities (Se) and specificities (Sp) were calculated across a range of sucrose concentrations. Ulcer grading was performed blindly by one observer; and the results were validated by comparing them with that of two other observers, and calculating the level of agreement. Cut-off values were selected manually to optimize Se. The prevalence of GL, GDL, SQL, and CSL was 83, 70, 53 and 58% respectively. At the selected cut-offs, Se ranged from 51 to 79% and Sp ranged from 43 to 72%, depending upon the lesion type and time of sampling.

Conclusions

Blood sucrose is neither a sensitive or specific test for detecting EGUS in this population of adult horses with naturally occurring gastric ulceration. Further studies aimed at evaluating the performance characteristics of the test in different study populations are warranted. Given the limitations of endoscopy, due consideration should also be given to alternative methods for comparison of blood sucrose with a gold standard.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-017-0284-1) contains supplementary material, which is available to authorized users.

The effects of dose and diet on the pharmacodynamics of esomeprazole in the horse

BACKGROUND

Esomeprazole warrants further investigation as a treatment for equine gastric ulcer syndrome.

OBJECTIVES

To investigate the duration of intraday acid suppression achieved with two doses of esomeprazole under two dietary conditions.

STUDY DESIGN

A four way crossover design.

METHODS

Six adult Thoroughbreds instrumented with percutaneous gastrotomy tubes were used. Intragastric pH was measured for continuous 23 h periods (08.00-07.00 h) for 6 consecutive days (Days 0-5). Baseline data was recorded on Day 0 and esomeprazole was administered on Days 1-5. Two doses (0.5 and 2.0 mg/kg bwt/day per os once daily) and two diets (a high grain/low fibre (HG/LF) and ad libitum hay (HAY) diet) were studied. Data for the percentage of time pH was above 4 (%tpH>4) and median intraday pH was reported for two measurement points and analysed using generalised estimating equations.

RESULTS

An inconsistent effect of both diet and dose was evident with mean %tpH>4 and mean of the median intraday pHs typically higher at the 2.0 mg/kg bwt dose and in HG/LF diet. A cumulative effect of dosing was present with the magnitude of acid suppression observed on Day 5 consistently higher than that observed on Day 1. The magnitude of acid suppression, at measurement point 1, compared favourably with previous reports on omeprazole and exceeded human therapeutic breakpoints for the 0.5 mg/kg bwt dose in the HG/LF diet and 2.0 mg/kg bwt dose in the HAY diet.

MAIN LIMITATIONS

Instrumentation may have modified gastric function and horses were not fasted or exercised.

CONCLUSIONS

The findings of the present study suggested that both dose and diet affect the response to esomeprazole in the horse and that a cumulative effect is present over the first 5 days of treatment. Further investigation into the clinical efficacy of esomeprazole and trials directly comparing esomeprazole and omeprazole appear to be warranted.