EXPRESS: Azotaemia and outcomes in male cats with initial and recurrent urethral obstruction: a multicentre retrospective study of 601 cats (2020-2024)

Objectives This study aimed to compare the prevalence and time to resolution of azotaemia between male cats presented with initial and recurrent urethral obstruction (UO), and to evaluate risk factors for extended duration of urethral catheterisation and hospitalisation. Methods A multicentre, retrospective study of male cats that underwent urethral catheterisation for UO was conducted. Cats were excluded if they did not have a UO on presentation, had previously diagnosed chronic kidney disease, had incomplete medical records or if they were referred by another clinic after decompression. Prevalence of azotaemia (serum or plasma creatinine > 140 µmol/L) and time to resolution was compared between cats with initial and recurrent UO. Risk factors evaluated for extended duration of catheterisation and hospitalisation included signalment, history of UO, history of lower urinary tract signs (LUTS), diet, recent medications, lifestyle (indoor-only or indoor-outdoor), housing status (single or multi-cat) and azotaemia on presentation. Results Cats were less likely to be azotemic on presentation if they had a history of UO (p = 0.015) or LUTS (p = 0.014). Azotaemic cats were 1.92 times more likely to undergo a longer duration of catheterisation compared with non-azotaemic cats (95%CI 1.40-2.65; p<0.001), and 1.81 times more likely to have a longer hospitalisation (95% CI 1.28-2.57; p < 0.001). Resolution of azotaemia was achieved in <48 hours in 70.1% (n=89/127; 95% CI 61.3-77.9) of cats that were azotaemic on presentation. Recurrent UO was not associated with longer time to resolution of azotaemia (p = 0.395). Conclusions and relevance Cats are less likely to present with azotaemia during recurrent UO episodes, which might be due to increased caregiver vigilance. Resolution of azotaemia occurred within 48 hours for most cats. There was no difference in catheterisation and hospitalisation duration between cats with initial and recurrent UO.