ID08 - Can We Predict Xanthinuria in Dogs with Leishmaniasis Undergoing Allopurinol Treatment? – a Retrospective Study

Abstract: Background- Xanthinuria is a common but inconsistent side-effect in dogs with leishmaniosis undergoing allopurinol treatment.
Hypothesis/Objectives- To evaluate potential predisposing factors to the development of xanthinuria in dogs with leishmaniosis treated with allopurinol.
Animals- Ninety dogs with leishmaniosis undergoing allopurinol treatment, recruited from three referral hospitals (one in Portugal and two in Spain) between 2012 and 2022.
Methods- A multicentric, retrospective, case-control study was conducted. Dogs with leishmaniosis that developed xanthinuria (crystals and/or uroliths) undergoing allopurinol treatment were selected and grouped (Xgroup). A control group consisting of dogs with leishmaniosis without xanthinuria after at least five months of allopurinol treatment was concurrently recruited (NXgroup). Medical records were reviewed, and clinical and laboratorial variables were compared between groups. Descriptive and non-parametric tests were used (p< 0.05).
Results- Forty-five dogs were included in each group. Groups were homogeneous for gender, weight, and reproductive status. Only age and serum alpha-1 globulins concentration were significantly different between groups. Dogs from Xgroup were younger than those from the NXgroup (median 4 years (range 1-10) versus 6 years (range 1-14), respectively; p=0.002). Before allopurinol onset, a higher percentage of dogs from the NXgroup had decreased serum alpha-1 globulin levels (40.5% versus 13.3% in the Xgroup, respectively; p=0.016). In Xgroup, median time to xanthinuria development after starting allopurinol was 150 days (range 4-2190).
Conclusions and clinical importance- This study highlights that young-adult age and normal serum alpha-1 globulin levels (before treatment) might be predisposing factors for the development of xanthinuria in dogs with leishmaniosis undergoing allopurinol treatment.