Iron profile evaluation in chronic kidney disease: a retrospective study of 46 dogs

The evaluation of iron metabolism in course of chronic kidney disease (CKD) is justified by the still growing number of studies in humans. Similar reports in veterinary patients are rare or completely missing. The aim of this study was the evaluation of the Iron Status in canine patients affected by CKD, and the assessment of a potential correlation between iron homeostasis, progression of the CKD, and presence of an acute phase response (APR). The medical records of dogs, referred for a nephrological evaluation from January 2007 to December 2009, were analyzed. Fortysix dogs with CKD were selected and compared with healthy dogs (n 5 28). Considering a cut-off hematocrit value (HCT) of 35%, CKD dogs were afterwards divided in 2 groups defined as ‘‘anemic’’ and ‘‘non-anemic’’. Based on the International Renal Interest Society (IRIS) guidelines, CKD dogs were further divided in stage II, III and IV. Iron Status was assessed by the evaluation of Total Iron, Ferritin, Total Iron Binding Capacity (TIBC), TIBC-saturation %, and haematological parameters together with an acute phase proteins profile comprehensive of C-reactive Protein (CRP), Haptoglobin (Hp), and Albumin (Alb). CRP, Hp and Ferritin were measured using immunoturbidimetric methods. The Urinary Protein to Creatinine ratio (UPC) was also evaluated. Iron deficiency in the CKD dogs was defined by the presence of at least one of the following: hypoferremia, hypoferritinemia, increased TIBC, and decreased TIBC-saturation. Thus a prevalence of iron deficiency of 43% (20/46) was achieved. The concomitant presence of the 4 cited abnormalities was detected in the 2% of dogs (1/46). Considering hypoferritinemia as a more specific estimation of iron deficiency, the prevalence gets to 11% (5/46). These findings suggest that iron abnormalities are common in CKD patients. A concurrent APR was detected in 36/46 dogs, potentially affecting the Iron Status. Indeed, Ferritin concentrations were higher in the CKD dogs than in healthy ones, while Total Iron and TIBC-saturation% were lower. In our population, ‘‘anemic’’dogs presented lower Total Iron and negative APP concentrations compared to the ‘‘nonanemic’’ ones, withUPC not different between groups. No significant differences in the iron profile were detected between IRIS stages. Further studies in a wider population of dogs with CKD, evaluating the prognostic role of iron profile and its potential impact on treatment strategies, are warranted.