Serum insulin-like growth factor-I concentration in cats with diabetes mellitus and acromegaly.
BACKGROUND
Serum insulin-like growth factor-I (IGF-I) has been used in place of serum growth hormone quantification for identifying acromegaly in diabetic cats. The utility of IGF-I as a screening test for acromegaly has not been critically evaluated. This retrospective study was performed to evaluate the usefulness of serum IGF-I concentration for identifying acromegaly.


OBJECTIVE
Serum IGF-I is a useful screening test for acromegaly in diabetic cats.


METHODS
A review was made of the medical records of 74 diabetic cats that had serum IGF-I quantified. The diabetes was classified as well controlled (15 cats), poorly controlled because of problems with the insulin treatment regimen, concurrent disease, or both (40), or poorly controlled with clinical findings consistent with acromegaly (19).


METHODS
A review of medical records was made.


RESULTS
Serum IGF-I concentration was significantly (P < .0001) increased in acromegalic diabetic cats, compared with well-controlled and poorly controlled diabetic cats. Sensitivity and specificity for serum IGF-I concentration were 84% (95%/ confidence interval [CI] = 60.4-96.6%) and 92% (95% CI = 81.3-97.2%), respectively. There was no significant correlation between serum IGF-I concentration and duration of insulin treatment (r = 0.23, P = .089), insulin dosage (r = 0.14, P = .30), age (r = 0.16, P = .12), and pituitary volume (r = 0.40, P = .11), but a modest correlation was found between serum IGF-I concentration and body weight (r = 0.48, P < .0001).


CONCLUSIONS
Results support the use of serum IGF-I concentration as a screening test for acromegaly in diabetic cats that have clinical findings supportive of the disease.
Berg
Rebecca I M
RI
Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Nelson
Richard W
RW
Feldman
Edward C
EC
Kass
Philip H
PH
Pollard
Rachel
R
Refsal
Kent R
KR
D000172:Acromegaly / Q000097:blood / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D002371:Cat Diseases / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D002415:Cats; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D005260:Female; D013006:Growth Hormone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D011863:Radioimmunoassay / Q000662:veterinary; D012016:Reference Values; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone