Not every horse owner has the resources for serial testing - repeated blood work or imaging - to judge the effectiveness of a medication or treatment and may need to learn how to objectively use clinical signs to assess their horse's progress.
Several years ago I suggested using a "0 to 10" assessment scale to help a horse owner use clinical signs in evaluating the effect of titrating her horse's pergolide dose.
If you've made changes (in medication, treatment, etc.) and don't see improvement, it should cue you to review
other basics - diet, teeth, parasites, ulcers, foot pain, etc. and perhaps review the diagnosis and treatment plan.
It's a good idea to do our follow up assessment before looking back at the previous one as this will help us do an objective assessment. If you've never used a 0-10 assessment scale, it may feel awkward at first (which is why its helpful to include a descriptive word or two).
The Clinical Signs Tracker chart (view or download below) can be use for tracking your horse's progress. On the first page, I've entered several clinical signs related to Insulin Resistance/Metabolic Syndrome and PPID (Cushing's disease) but which also apply to other conditions. The second page was left blank so you and your veterinarian can list other clinical signs you may want to track for other problems or injuries, such as increase or decrease in swelling, lameness/soundness during rehab, changes in a wound size or drainage.
Providing an ongoing objective assessment record can be a valuable tool for working with your veterinarian and keep both of you from guessing if a treatment is effective.