Cushing's disease in dogs and pet insurance: the test schedule, the deductible and the renewal premium

Cushing's as an insurance file: an older dog, a daily capsule, a blood test every quarter

Cushing's disease, or hyperadrenocorticism, is the body producing too much cortisol. Cornell University's Riney Canine Health Center describes two common forms: a small, usually benign pituitary tumor that drives the adrenal glands (80 to 85 percent of cases), and a tumor of the adrenal gland itself. Merck gives a similar split, about 85 percent pituitary-dependent and 15 percent adrenal-dependent. Merck states that most cases are treated with the adrenal enzyme inhibitor trilostane. Which test, which drug and which dose suit a given dog is a veterinarian's call; what follows reads the bills and the policy wording around that treatment, with no insurer ranked or recommended and every premium figure a published anchor, not a quote.

Trilostane reached the US market as Vetoryl capsules, approved by the FDA as of December 5, 2008 under NADA 141-291 for both pituitary-dependent and adrenal-dependent disease, according to the Federal Register notice of May 11, 2009. The current label on DailyMed (the National Library of Medicine's label database, version published December 18, 2025) lists capsule strengths of 5, 10, 20, 30, 60 and 120 mg and a starting dose of 1 to 3 mg per pound once a day, given with food. On the DailyMed trilostane listings checked October 30, 2026, Vetoryl was the only finished capsule product; the other 18 entries were bulk trilostane powder, which matters later for the medication clause.

For an insurer, three facts follow. First, the claim starts late: Merck places the disease mainly in middle-aged to older dogs, 7 to 12 years old. Second, it runs for years. Merck describes the prognosis for pituitary-dependent disease as good, with median survival estimated at 2 years with or without treatment, and cites a study of dogs on low-dose twice-daily trilostane with a median survival of 998 days (range 26 to 1,832 days). Third, it repeats on a timetable, because the label ties the monitoring to the drug. That timetable is the part of the bill an owner can actually count.

Counting the visits the Vetoryl label calls for

The label's dosing section is specific. After about 10 to 14 days at the starting dose, the dog is re-examined with an ACTH stimulation test taken 4 to 6 hours after the capsule, plus serum biochemistry "with particular attention to electrolytes, and renal and hepatic function." The same check is repeated 10 to 14 days after every dose change. Once the dose is right, the label says to "re-examine the dog at 30 days, 90 days and every 3 months thereafter," and lists the minimum for each visit: a history and physical examination, an ACTH stimulation test and serum biochemistry.

Counting those visits gives the shape of a year. The table assumes the dose is adjusted once or twice before it settles, which is an illustration, not a prediction; some dogs need more changes and the label adds a recheck for each one. It also leaves out unscheduled visits, which the label calls for if the dog shows signs such as vomiting, diarrhea or lethargy.

Each visit on that list is three billable items, not one: an exam, an ACTH stimulation test (a blood sample, an injected dose of ACTH, a timed second sample) and a chemistry panel with electrolytes. A dog stable for a full year still produces four of these visits plus twelve months of capsules. If the dose changes again in year three, that year gains another recheck, so the later-year figure is a floor.

What a published lab fee covers, and what it leaves out

University teaching hospitals do not post a client price for a Cushing's recheck the way they post some surgery estimates, but several university diagnostic laboratories publish what they charge for the tests themselves. Those are fees billed to the veterinarian or clinic that submits the sample. They are useful as a floor, because they show how much of a recheck bill is laboratory work, but they are not what an owner pays at the front desk.

Put together, the published laboratory work for one recheck is an ACTH pair at $40 to $63 across the three labs plus Iowa State's $38 small animal chemistry profile, or about $78 to $101. The owner's invoice adds the examination, the injected ACTH, the technician time for two timed blood draws and the clinic's own markup, and university laboratories do not publish those parts of the bill. That gap is why the worked example below states its own input for a whole visit rather than borrowing a lab fee as if it were a bill.

Diagnosis costs more than a recheck because it uses more tests. Cornell lists a complete blood count, chemistry panel and urinalysis to assess the dog's overall health, with adrenal function testing (a low dose dexamethasone suppression test as the preferred screen in most cases, with the ACTH stimulation test and urine cortisol to creatinine ratio as other options) and often an abdominal ultrasound. Merck adds that no single test or combination is 100 percent accurate, which is one reason a workup can stretch across more than one visit.

An annual deductible repeats on a claim that never closes

Most accident and illness policies apply the deductible once per policy year. On a chronic claim that means the owner pays it again at every renewal. A few forms work differently. The posted Trupanion policy form TRU-00001 (August 2011 edition) defines the deductible as the amount of claims "for any one condition or injury" the owner pays first, and says that once it has been met for a specific condition, "the policy will pay out all future losses for that condition at the selected co-insurance rate." The same form states "unlimited lifetime coverage" with no annual or per-claim cap.

Running the example bills through two structures shows what that difference is worth. Both use 80 percent reimbursement and a $500 deductible. Structure A takes the deductible every policy year and has a $5,000 annual limit. Structure B takes the deductible once for the condition and has no limit. Neither is any insurer's actual plan; they isolate one clause each.

The repeating deductible costs $400 a year in this illustration (the $500 deductible times the 80 percent the insurer would otherwise have paid), every year after the first. Over a four-year claim that is $1,200, more than a full year of the smaller dog's medication. A $5,000 annual limit, by contrast, never binds on routine Cushing's care in these numbers. It binds only in a year when something else lands on top, here a $4,000 hospital stay of the kind the label's warnings about adrenal crises and serious reactions make possible.

Limits that work per incident or per condition, and that do not reset at renewal, are a different and harsher problem for any lifelong claim. The diabetes guide runs that case year by year, and the arithmetic carries over to Cushing's unchanged, so it is not repeated here. The limits decoder explains how each limit type is written.

The renewal premium at which the Cushing's claim stops paying for itself

The other side of the ledger is the premium, and for a dog of 7 to 12 it is rising. Several insurers say so in their own documents. The AKC Pet Insurance North Carolina sample policy (IAIC PPI AI POL 007 NC 0421) lists the reasons "Premiums may increase at renewal for: Pet age, veterinary cost inflation, actuarial changes, address changes, Annual Limit increase and other Policy parameters." Embrace's FAQ says "Premiums are based on the current age of your pet" and that the premium "may increase due to the age of your pet at renewal." The 2011 Trupanion form takes the opposite approach: premium is set from factors at enrollment, including age at enrollment, and "will not change due to your pet aging or your pets individual claims experience," though it can still change once a year with the overall cost of veterinary care.

Industry averages show the general direction. The North American Pet Health Insurance Association's 2026 State of the Industry highlights (published June 21, 2026) give the average US annual premium for an accident and illness dog policy as $625 in 2021, $640 in 2022, $675 in 2023, $749 in 2024 and $836 in 2025, an 11.5 percent rise in the last year. Those are averages across all insured dogs of every age, so they describe the market's direction, not the age curve any one dog will follow.

A useful test is to turn the steady-year reimbursement into a monthly figure and compare it with the premium. In Structure A, the 20 lb dog's later years return $1,280, or about $107 a month; the 65 lb dog's return $2,000, or about $167 a month. If the renewal premium climbs past those figures, the Cushing's claim alone no longer returns what the policy costs. The policy still covers everything else that can happen to an old dog, so that is a prompt to re-read the policy, not a rule to cancel.

Anchors are AdvisorSmith published premium research averages as labelled on each breed page, not quotes and not age-specific; a senior dog's actual renewal premium can sit well above a breed average. Break-even figures come from the illustration's inputs and change with your own bills. Percentage arithmetic of this kind can be checked on CalculatorVillage.

The weight of the dog matters as much as the breed, and pairing each breed with one of the two example dogs is the editors' simplification, since dogs within a breed vary in size and dose. Run the same steps with your clinic's recheck estimate, your pharmacy's monthly price and your actual renewal offer. The NAIC Pet Insurance Model Act, Section 4A(4), asks insurers to disclose "whether the pet insurer reduces coverage or increases premiums based on the insured's claim history, the age of the covered pet or a change in the geographic location of the insured," so the information needed to project the premium should be in the disclosure, where your state has adopted the model. The premium increase guide explains how to read a renewal notice line by line.

Renewal and chronic-condition wording in six insurer documents

The documents below were read on October 30, 2026. Sample forms are single-state examples, and the rows are not in any order of merit. An adjuster reads your dog's own form, not these samples.

One rule sits behind most of these forms. The NAIC model act defines a chronic condition in the same words Spot uses, and its Section 3F says a condition covered on a policy "cannot be considered a preexisting condition on any renewal of the policy." The model binds only where a state has adopted it. The practical point for a Cushing's dog is that the protection depends on continuity: a lapse, a switch to another insurer, or a plan change the insurer treats as a new enrollment (the AKC sample warns that some changes can "reset the Waiting Period and the determination of Pre-existing Conditions") turns a covered disease into an excluded one. The switching guide lists what resets.

Compounded trilostane and the medication definition

Small dogs sometimes need doses that do not match a capsule size, and owners are sometimes offered compounded trilostane. That choice can move a claim from paid to refused. The FDA's animal drug compounding page (content current as of August 27, 2026) states that "Animal drugs compounded from bulk drug substances are not FDA-approved" and have not been reviewed for safety, effectiveness or manufacturing quality, although they can be medically necessary when no approved drug fits. A product compounded from finished Vetoryl capsules is a different legal case from one made from powder, and the pharmacy can say which it is.

The policy definitions split along that line. The Spot sample pays for "Prescription medications prescribed by a veterinarian and approved by the Food and Drug Administration (FDA)." Embrace reimburses FDA-approved and Homeopathic Pharmacopoeia drugs. The Figo sample defines medications as FDA-approved or Homeopathic Pharmacopoeia drugs, and mentions pharmacist compounding in the context of over-the-counter drugs. The MetLife sample is the broadest read here: medication "may be dispensed directly by a Veterinarian, dispensed or compounded by a pharmacist, or available over the counter, as long as it is prescribed by a Veterinarian." If your veterinarian suggests a compounded product, ask the insurer before the first refill whether it will be repaid. The epilepsy guide works through the same FDA-approval clause for a drug class where it comes up even more often.

The conditions that travel with Cushing's, and the related-condition clause

Cornell lists the medical conditions associated with Cushing's syndrome: urinary tract infections, skin infections, neurologic problems such as seizures and circling, blood clots, sudden blindness, gallbladder disease (mucocele) and diabetes mellitus. Merck adds that about 10 percent of dogs with hyperadrenocorticism have diabetes at the same time. For an insured dog diagnosed after enrollment, those conditions are usually just more covered claims, subject to the same deductible and limit. For a dog whose Cushing's is pre-existing, they are where the arguments start. Treatment can add one more: the Merck Veterinary Manual lists trilostane among the causes of adrenocortical failure, the opposite disease, and the Addison's disease insurance guide shows how a related-condition clause could read a diagnosis that follows Cushing's treatment.

The wording that decides it is the related-condition language. The Spot sample counts as pre-existing any condition "related to, secondary, or resultant from a pre-existing condition," and the Figo sample excludes a chronic condition observed before cover "and any related conditions." Neither form lists which conditions it treats as related to Cushing's. An insurer reading a urinary infection or a diabetes diagnosis as secondary to excluded Cushing's could refuse it; one could instead treat it as a new condition. Ask before buying how the insurer would treat each condition on Cornell's list. For diabetes in particular, the diabetes guide explains how insurers treat it on its own, and the pre-existing conditions guide shows how records are read to date a condition.

Five answers from the insurer that move the numbers above

A Cushing's claim is decided less by the surgery and hospital clauses that sell policies and more by definitions that sit deep in the form. Each of these five questions targets one of them, and each answer changes a line in the example above.

1. Is Cushing's disease covered as a chronic condition, and is it excluded anywhere as hereditary or congenital for this breed?
2. Is the deductible annual or per condition, and will a chronic condition diagnosed this year keep the same deductible treatment at renewal?
3. Are exam fees, ACTH stimulation tests and chemistry panels at scheduled rechecks paid as covered treatment once a condition is diagnosed, or treated as routine monitoring?
4. Is trilostane repaid from any pharmacy, and is a compounded product repaid, or only FDA-approved capsules?
5. How is the premium expected to change with age at each renewal, and does the insurer raise premiums or reduce coverage because of claims?

Ask for the answers by email so they can be kept with the policy. The MetLife sample, for example, defines Diagnostics as tests performed "for the purpose of determining what disease or condition explains symptoms," which plainly fits the first workup; whether a quarterly recheck on a known disease falls under the same heading or under treatment is the kind of point worth settling before the receipts pile up.

Owners of a predisposed breed have the most reason to start early. Merck lists the Poodle (especially the Miniature), the Dachshund, the Boxer, the Boston Terrier, the Yorkshire Terrier and the Staffordshire terriers; Cornell's pituitary-dependent list adds the Bichon Frise, Border Terrier, Jack Russell Terrier, Lhasa Apso and Miniature Schnauzer. For a dog in that group that is still years from the usual age of onset, the useful next read is the senior dog guide, because it covers the renewal years in which a Cushing's claim would most likely land.

A Cushing's policy timeline, from age seven to the trilostane years

Merck says the disease occurs mostly in dogs 7 to 12 years old, and a study it cites of low-dose trilostane reported a median survival of 998 days, so the clauses that matter change as the dog moves through those years. The stages below follow that order; the last one applies at any point once signs are on record without a policy in force.