# Investigation of association between serum C‐reactive protein concentrations and proteinuria in dogs

## TL;DR

This study explores the link between inflammation markers and proteinuria in dogs, finding that inflammation is associated with higher proteinuria rates.

## Contribution

The study identifies a novel association between serum C-reactive protein concentrations and proteinuria in dogs, independent of specific diseases.

## Key findings

- Proteinuria was less prevalent in dogs with chronic enteropathy compared to others.
- Chronic hepatitis and pancreatitis were associated with higher prevalence of proteinuria.
- Serum C-reactive protein concentration independently increased the odds of proteinuria.

## Abstract

Identify if serum C‐reactive protein concentrations and specific diseases are associated with proteinuria (defined as urine protein:creatinine ratio >0.2) in dogs without known pathological pre‐renal, renal or post‐renal causes.

Hypothesis generating retrospective study. Dogs with contemporaneous urine protein:creatinine ratio and serum C‐reactive protein concentrations and without known causes of pathological pre‐renal, renal or post‐renal causes of proteinuria were included. Continuous and categorical variables were compared between groups using non‐parametric statistics, and multivariable logistic regression analyses evaluated associations between specific diseases or selected clinicopathological variables (including serum C‐reactive protein concentrations) and proteinuria.

Seventy‐one overtly proteinuric (urine protein:creatinine ratio >0.5), 74 borderline proteinuric (urine protein:creatinine ratio 0.21 to 0.5) and 234 non‐proteinuric dogs (urine protein:creatinine ratio ≤.2) were included. Proteinuria (urine protein:creatinine ratio >0.2) was less prevalent in dogs diagnosed with chronic enteropathy (11% [4/35] vs. 41% [141/344]; P < .001) compared to the rest of the population. Proteinuria was more prevalent in dogs with chronic hepatitis (71% [10/14] vs. 37% [135/365]) and tended to be more prevalent in dogs with pancreatitis (57% [12/21] vs. 37% [133/358]; P = .103) compared to the rest of the population. On multivariable analysis, serum C‐reactive protein concentration was independently associated with increased odds of proteinuria (OR = 1.031 [95% CI: 1.012 to 1.051]; P = .001) and a diagnosis of chronic enteropathy was independently associated with decreased odds of proteinuria (OR = 0.21 [95% CI: 0.064 to 0.681]; P = .009).

Systemic inflammation might be associated with proteinuria in dogs, although further investigations to evaluate if proteinuria resolves following the resolution of these conditions are required to confirm any causal association.