{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T16:57:46Z","timestamp":1770224266108,"version":"3.49.0"},"reference-count":25,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2017,12,14]],"date-time":"2017-12-14T00:00:00Z","timestamp":1513209600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>The increase of urinary fractional excretion of phosphorus (uFEP) may indicate phosphorus retention before the onset of hyperphosphatemia in the early stages of chronic kidney disease (CKD). The hypothesis of this study is whether uFEP may increase during the early stage of CKD as a compensatory mechanism to prevent hyperphosphatemia as well as whether hyperphosphatemia in the late stages is associated with increase or decrease in uFEP in dogs with naturally occurring CKD; therefore, the aim of this study was to determine the uFEP in CKD dogs with different stages. Forty-nine CKD dogs were included, and they were divided into stage 1 (serum creatinine &lt; 1.4 mg\/dL), stage 2 (serum creatinine 1.5 to 2.0 mg\/dL), stage 3 (serum creatinine 2.1 to 5.0 mg\/dL) and stage 4 (serum creatinine &gt; 5.0 mg\/dL), according to the IRIS staging criteria. The stage 3 was subdivided into stage 3-A (serum creatinine 2.1 to 3.5 mg\/dL) and stage 3-B (serum creatinine 3.6 to 5.0 mg\/dL). The control group comprised 10 dogs, and uFEP \u2264 40% was considered as normal. A progressive increase in uFEP along the progression of CKD was found. However, similar results of uFEP levels were observed in late CKD, since there were no differences between stages 3 (A, B) and 4. Interestingly, some CKD dogs with stage 4 showed normal or reduced uFEP, besides hyperphosphatemia; conversely, some dogs in early CKD had increased uFEP values and normophosphatemia. Our findings suggest that uFEP may act as a compensatory mechanism to avoid the onset of hyperphosphatemia in early CKD, but not in later stages. uFEP assessment may be considered as an additional tool for the diagnostic and monitoring of phosphate disorders in dogs with CKD, since it may help to identify disturbances of phosphorus balance. More studies are needed to elucidate the role of uFEP in phosphorus homeostasis in dogs with CKD.<\/jats:p>","DOI":"10.3390\/vetsci4040067","type":"journal-article","created":{"date-parts":[[2017,12,14]],"date-time":"2017-12-14T04:30:55Z","timestamp":1513225855000},"page":"67","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Urinary Fractional Excretion of Phosphorus in Dogs with Spontaneous Chronic Kidney Disease"],"prefix":"10.3390","volume":"4","author":[{"given":"C\u00ednthia","family":"Martorelli","sequence":"first","affiliation":[{"name":"Department of Veterinary Internal Medicine, School of Veterinary Medicine and Animal Science, University of S\u00e3o Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, S\u00e3o Paulo, SP 05508-270, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M\u00e1rcia","family":"Kogika","sequence":"additional","affiliation":[{"name":"Department of Veterinary Internal Medicine, School of Veterinary Medicine and Animal Science, University of S\u00e3o Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, S\u00e3o Paulo, SP 05508-270, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8683-9960","authenticated-orcid":false,"given":"Fernanda","family":"Chacar","sequence":"additional","affiliation":[{"name":"Department of Veterinary Internal Medicine, School of Veterinary Medicine and Animal Science, University of S\u00e3o Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, S\u00e3o Paulo, SP 05508-270, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4031-1175","authenticated-orcid":false,"given":"Douglas","family":"Caragelasco","sequence":"additional","affiliation":[{"name":"Department of Veterinary Internal Medicine, School of Veterinary Medicine and Animal Science, University of S\u00e3o Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, S\u00e3o Paulo, SP 05508-270, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ana","family":"De Campos Fonseca Pinto","sequence":"additional","affiliation":[{"name":"Department of Veterinary Internal Medicine, School of Veterinary Medicine and Animal Science, University of S\u00e3o Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, S\u00e3o Paulo, SP 05508-270, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carla","family":"Lorigados","sequence":"additional","affiliation":[{"name":"Department of Veterinary Internal Medicine, School of Veterinary Medicine and Animal Science, University of S\u00e3o Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, S\u00e3o Paulo, SP 05508-270, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"L\u00facia","family":"Andrade","sequence":"additional","affiliation":[{"name":"Division of Nephrology, School of Medicine, University of S\u00e3o Paulo, Av. Dr. Arnaldo, 455, S\u00e3o Paulo, SP 01246-903, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,12,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1111\/vec.12034","article-title":"Evidence-based step-wise approach to managing chronic kidney disease in dogs and cat","volume":"23","author":"Polzin","year":"2013","journal-title":"J. Vet. Emerg. Crit. Care"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1111\/vec.12032","article-title":"The role of phosphorus in the pathophysiology of chronic kidney disease","volume":"23","author":"Geddes","year":"2013","journal-title":"J. Vet. Emerg. Crit. 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