Evaluation of the association between initial proteinuria and morbidity rate or death in dogs with naturally occurring chronic renal failure

Objective-To determine whether urine protein-to-creatinine ratio (UP:C) greater than or equal to 1.0 at initial diagnosis of chronic renal failure (CRF) is associated with greater risk of development of uremic crises, death, and progression of renal failure in dogs. Design-Prospective cohort study. Animals-45 dogs with CRF. Procedure-Dogs were prospectively assigned to 2 groups on the basis of initial UP:C < 1.0 or greater than or equal to 1.0. The association between magnitude of proteinuria and development of uremic crises and death was determined before and after dogs with initial UP:C greater than or equal to 1.0 were assigned to 3 subgroups and compared with dogs with initial UP:C < 1.0. Changes in reciprocal serum creatinine concentration were used to estimate decrease in renal function. Results-Initially, dogs had similar clinical characteristics with the exception of systolic blood pressure and UP:C. Relative risks of development of uremic crises and death were approximately 3 limes higher in dogs with UP:C greater than or equal to 1.0, compared with dogs with UP:C < 1.0. Relative risk of adverse outcome was approximately 1.5 times higher for every 1-unit increment in UP:C. The decrease in renal function was of greater magnitude in dogs with UP:C greater than or equal to 1.0, compared with dogs with UP:C < 1.0. Conclusions and Clinical Relevance-Initial UP:C greater than or equal to 1.0 in dogs with CRF was associated with greater risk of development of uremic crises and death, compared with dogs with UP:C < 1.0. Initial determinations of UP:C in dogs with naturally occurring CRF may be of value in refining prognoses.