Open AccessN ‐Acetyl‐β‐ d ‐Glucosaminidase Index as an Early Biomarker for Chronic Kidney Disease in Cats with Hyperthyroidism
Author(s) -
Lapointe C.,
Bélanger M.C.,
Dunn M.,
Moreau M.,
Bédard C.
Publication year - 2008
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/j.1939-1676.2008.0168.x
Subject(s) - cats , medicine , euthyroid , azotemia , kidney disease , renal function , gastroenterology , urine specific gravity , biomarker , urine , endocrinology , urology , hormone , biochemistry , chemistry
Background: Hyperthyroid cats are at risk of developing azotemic chronic kidney disease (CKD) and diagnostic tools currently used to screen for CKD in hyperthyroid cats are either unreliable or impractical. Hypothesis: Urine N ‐acetyl‐β‐ d ‐glucosaminidase index (NAG i ) is a good biomarker for azotemic CKD in hyperthyroid cats. Animals: Twenty‐four newly diagnosed nonazotemic hyperthyroid cats and 10 healthy cats. Methods: All cats were evaluated for hyperthyroidism at baseline. Hyperthyroid cats were treated with methimazole and reevaluated once euthyroid. At the end of the study, cats were divided into 3 groups: healthy cats, nonazotemic, and azotemic euthyroid cats. Baseline group characteristics were compared to predict azotemic CKD. The influence of treatment on NAG i was evaluated. Results: Baseline NAG i was significantly different among groups ( P = .004). Azotemic cats had a higher median value (13.12 U/g) when compared with healthy cats (1.38 U/g). With NAG i >2.76 U/g, negative and positive predictive values for development of azotemia were 77.7 and 50%, whereas the combination of a urine specific gravity (USG) ≤1.035 and T 4 >7.80 μg/dL enhanced predictive values to 88.9 and 83.3%, respectively. NAG i values decreased significantly over time in treated nonazotemic cats. Conclusions and Clinical Relevance: Baseline NAG i did not differentiate azotemic from nonazotemic euthyroid cats. NAG i could be used to assess renal function during medical therapy allowing the clinician to adjust methimazole dosage accordingly. The combination of USG and T 4 could optimize identification of appropriate candidates for permanent treatment of hyperthyroidism.