Prevalence of adverse events and their effect on completion of high speed treadmill exercise tests at a single institution (2000-2015).

The research studied the occurrence of adverse events during high speed treadmill (HSTM) exercise tests on horses at one institution over a 15-year period. The study found that these events, while rare, can significantly reduce the likelihood of a test’s completion but mostly do not prevent a diagnosis.

Research Objective

This study aims to identify and analyze any adverse events occurring throughout high-speed treadmill exercise tests at a single institution, using the data recorded from 2000 to 2015. The research also sought to determine how these events affected the chance of the exercise test being completed.

Research Methodology

• The study design was retrospective, reviewing all records from a past time frame.
• Pearson’s chi-square test, a statistical test used to identify relationships between variables, was used to determine the significant differences in frequencies of adverse events between complete and incomplete high-speed treadmill exercise tests.
• Two Firth logistic regression models were employed to establish the likelihood of completing an exercise test given the presence of an adverse event and the likelihood of test completion for each type of adverse event.

Research Results

• Out of a total of 1003 horses presented for HSTM evaluation, 900 underwent exercise testing, of which 807 (or 90%) were completed.
• Adverse events, which can include any unexpected medical or behavioral incidents, occurred in 15% of high-speed treadmill exercise tests; 71% of these incidents did not impact the ability to complete HSTM testing.
• Adverse events significantly but variably decreased the likelihood of exercise test completion.
• About two-third of the exercise tests that didn’t complete were prematurely terminated due to poor performance abnormalities. Despite the incompletion, diagnosis of the cause(s) of poor performance was usually achieved.

Conclusion

This research supports the continuing use of high-speed treadmill exercise testing for the examination of horses with poor performance. While the occurrence of adverse events can reduce the likelihood of completing these tests, they aren’t frequent, and in a majority of cases, the exercise tests determined the cause of poor performance even when not completed. However, the study noted limitations due to variable data recording by different personnel during the study period and the potential bias of evaluating tests, not individual horses which could experience multiple training and testing episodes.