Study Start Date: 08/01/2006
Study End Date: 01/30/2007

Risk Factors for Cats with Idiopathic Hypercalcemia

The most common causes of hypercalcemia in cats have historically been malignancy-associated hypercalcemia and chronic renal failure. However, within the past 10 years idiopathic hypercalcemia (IHC) has been increasingly frequently observed, and is thought by some to now be the leading cause of hypercalcemia in cats. Currently, limited data exists regarding risk factors for development of IHC.

Cats that develop IHC often have subtle clinical signs that wax and wane, and the magnitude of hypercalcemia in IHC cats is often relatively small. However, IHC can be a risk factor for the development of calcium-containing uroliths. IHC also appears to be a risk factor for the development of chronic renal failure, though this may take months or years to occur. The frequency of occurrence for the diagnosis of IHC is increasing dramatically in the USA. Increased morbidity and mortality associated with IHC are the expected outcome for unrecognized and untreated hypercalcemia.

The cause(s) of IHC in cats remains elusive. This survey will detail dietary intake, supplements, environmental factors, and general husbandry practices of both normal control cats and cats with idiopathic hypercalcemia.

Study Design:
Prospective, Retrospective, Case-controlled, Survey

Inclusion criteria:
Affected cats: ionized hypercalcemia, creatinine < 2.2 mg/dl, PTH 0-4 pmol/L (normal range), no obvious other causes for hypercalcemia (especially no malignancy or advanced renal disease).
Controls: apparently normal based on history and physical examination; total calcium in normal range; creatinine < 2.2 mg/dl.

Exclusion Criteria:
Creatinine > 2.2 mg/dl; PTH > 4 pmol/L in affected hypercalcemic cats.

Study Sample Size:
200 IHC-affected cats; 400 control cats.

Study Controls:
2 case controls selected by DVM practice in which cat with idiopathic hypercalcemia was identified (see inclusion criteria above).

Costs/Reimbursements:
$20.00 to cat owners that complete the survey. $20.00 to DVM that successfully completes medical information form for BOTH affected and control cats. There is an option to decline these payments and give the money back for future studies of cats with idiopathic hypercalcemia.

Informed Consent:
Participants will be required to fill out an informed consent form for both IHC and control cats.

Full Disclosure information:

• The study is funded by a grant from Waltham Center for Pet Nutrition.
• The investigators do not have any conflict of interest.
• The study will be published if results are negative
• The study will be not be reported on VIN
• The authors will not acknowledge VIN if the study is published