Prognostic indicators associated with 2-week survival and postoperative antimicrobial use following ovariohysterectomy for canine pyometra from 2012 to 2021: a multicenter retrospective cohort of 470 cases

Objective This study aimed to retrospectively evaluate factors associated with 2-week survival following ovariohysterectomy for pyometra in dogs. Animals This study included 470 intact bitches that underwent ovariohysterectomy for pyometra. Methods In this multi-institutional retrospective cohort study, medical records were reviewed for clinical data, including signalment, duration of clinical signs, blood count findings, presence of septic peritonitis, culture and susceptibility results, antibiotics prescribed and duration, and survival at 2 weeks postoperatively (from the medical record or via owner contact). A univariable analysis was performed due to the low mortality rate to evaluate the association between variables and 2-week survival. Results Four hundred and fifty-two dogs survived to discharge, of which 10 dogs (2.2%) did not survive the 2-week follow-up. Eighteen dogs (3.8%) did not survive to discharge (DNSD). Post-discharge 2-week survival was 97.8% (442/452) and was associated with younger age and the absence of pre-operative azotemia, hyperkalemia, and hypoglycemia ( p -values: 0.005, 0.043, 0.004, and 0.015, respectively). No association was found with pyometra type (open vs. closed), oral antibiotic use or duration, or any other assessed variable ( p -values > 0.05). Clinical significance Younger dogs that were presented for pyometra without azotemia, hyperkalemia, and/or hypoglycemia had improved 2-week postoperative survival. An association between postoperative discharge antibiotic use and 2-week survival was not identified in this study. Further studies with greater statistical power are needed to evaluate the potential effect of postoperative antibiotic use on survival.