Comparison of Single, Averaged, and Pooled Urine Protein:Creatinine Ratios in Proteinuric Dogs Undergoing Medical Treatment.

BACKGROUND: Monitoring urine protein:creatinine ratios (UPC) in dogs with protein-losing nephropathy (PLN) is challenging because of day-to-day variation in UPC results. HYPOTHESIS/OBJECTIVES: Determine whether single, averaged, or pooled samples from PLN dogs receiving medical treatment yield comparable UPCs, regardless of degree of proteinuria. ANIMALS: Twenty-five client-owned PLN dogs receiving medical treatment. METHODS: UPC ratios were prospectively measured in each dog utilizing 3 methods: single in-hospital sample (day 3), average sample (days 1-3), and pooled sample (equal pooling of urine from days 1-3). Bland-Altman analysis was performed to evaluate agreement between methods for all dogs, as well as in subgroups of dogs (UPC ≤4 or UPC >4). RESULTS: For all dogs, Bland-Altman log-transformed 95% limits of agreement were -0.07-0.18 (single versus pooled UPC), -0.06-0.16 (single versus average UPC), and -0.06-0.04 (pooled versus average UPC). For dogs with UPC ≤4, Bland-Altman 95% limits of agreement were -0.42-0.82 (single versus pooled UPC), -0.38-0.76 (single versus average UPC), and -0.27-0.25 (pooled versus average UPC). For dogs with UPC >4, Bland-Altman 95% limits of agreement were -0.17-2.4 (single versus pooled UPC), -0.40-2.2 (single versus average UPC), and -0.85-0.43 (pooled versus average UPC). CONCLUSIONS AND CLINICAL IMPORTANCE: UPC ratios from all methods were comparable in PLN dogs receiving medical treatment. In PLN dogs with UPC >4, more variability between methods exists likely because of higher in-hospital results, but whether this finding is clinically relevant is unknown.

Relationship among serum creatinine, serum gastrin, calcium-phosphorus product, and uremic gastropathy in cats with chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) in cats is associated with gastrointestinal signs commonly attributed to uremic gastropathy. Consequently, patients often are treated with antacids and gastrointestinal protectants. This therapeutic regimen is based on documented gastric lesions in uremic humans and dogs, but the nature and incidence of uremic gastropathy in cats are unknown. HYPOTHESIS/OBJECTIVES: Evaluate uremic gastropathy in CKD cats to facilitate refinement of medical management for gastrointestinal signs. ANIMALS: Thirty-seven CKD cats; 12 nonazotemic cats METHODS: Stomachs were evaluated for the presence of classic uremic gastropathy lesions. Histopathologic lesions were compared with serum creatinine concentrations, calcium-phosphorus product (CPP), and serum gastrin concentrations. RESULTS: Gastric ulceration, edema, and vascular fibrinoid change were not observed. The most important gastric lesions in CKD cats were fibrosis and mineralization. Sixteen CKD cats (43%) had evidence of gastric fibrosis of varying severity and 14 CKD cats (38%) had gastric mineralization. CKD cats were more likely to have gastric fibrosis and mineralization than nonazotemic controls (P = .005 and P = .021, respectively). Only cats with moderate and severe azotemia had gastric mineralization. CPP was correlated with disease severity; severely azotemic CKD cats had significantly higher CPP when compared with nonazotemic controls, and to mildly and moderately azotemic cats (P < .05). Gastrin concentrations were significantly higher in CKD cats when compared with nonazotemic controls (P = .003), but increased concentrations were not associated with gastric ulceration. CONCLUSIONS AND CLINICAL IMPORTANCE: Uremic gastropathy in CKD cats differs from that described in other species and this difference should be considered when devising medical management.