Survival time and prognostic factors in cats with suspected acute pyelonephritis
Jordan R Fletcher, Arnon Gal, Elizabeth Dill-Macky, Emily K Cook, Louise M Harris, John T Mackie, Nicholas MalikidesAbstract
Background
Although acute pyelonephritis (APN) is considered to have a better prognosis than other causes of acute kidney injury (AKI) in cats, survival time and prognostic factors are poorly defined.
Hypothesis/Objectives
To determine survival time and prognostic factors influencing survival time in cats suspected of APN.
Animals
Fifty-four client-owned cats with suspected APN.
Methods
A retrospective cohort study was designed to review medical records between June 2017 and December 2025 for clinical data and survival time. Overall survival time was assessed using Kaplan–Meier analysis. Cox proportional hazard regression univariable screening then multivariable modeling identified factors associated with survival. Clinical features of survivors and non-survivors to 30-days after presentation were compared.
Results
Median survival time (MST) was 390 days (95% CI, 153-774 days). Cats that experienced less than 50% reduction or any increase in percentage change in serum creatinine concentration between hospital admission and discharge or euthanasia (sCrΔ%) had significantly higher hazards of death than cats experiencing greater than 50% reduction in sCrΔ%, after adjusting for International Renal Interest Society (IRIS) AKI grade and admission temperature (adjusted hazard ratios [HRs], 8.4 × 104-1.1 × 106; 95% CIs, 4.9 × 102-3.1 × 108; P < .001). No other factors, including pre-existing chronic kidney disease, infecting bacterial isolate, or antimicrobial regimen used, were independently associated with overall survival time.
Conclusions and clinical importance
Cats suspected of APN have favorable long-term prognosis. Less reduction or any increase in sCrΔ% was associated with shorter survival time, with the prognostic effect strongly influenced by IRIS AKI grade and temperature at admission.