Impacts of clinical backgrounds and intervention strategies on duration of intravenous antibiotics treatments in patients diagnosed with calculous pyelonephritis: A single-center retrospective study.

Objectives: There are limited information that need to do appropriate treatment including duration of antibiotic treatments, timing of urinary drainage and pathogenesis of bacteria in calculous pyelonephritis. In the present study, we investigated real-world data on clinical features and succeeded treatment strategies in calculous pyelonephritis cases in our hospital, then, aimed to make predictive model estimating duration of intravenous antibiotics treatment.

Methods: Participants were 163 consecutive patients diagnosed with calculous pyelonephritis who underwent antibiotics treatments between 2017 and 2023 in our in-patients' clinic. Candidates for explanatory variables that may affect duration of antibiotic treatments were age, gender, body mass index, stone location, stone size, septic status, blood culture, urine drainage, indwelling urethral catheter, diabetes mellitus and steroid intake.

Results: Duration of intravenous antibiotics treatment was 6 days in median (IQR: 4-8 days). Indwelling DJ stent or percutaneous nephrostomy were undergone in 74 (45.4 %) patients. Multiple regression analysis revealed that gender, age, indwelling urethral catheter, septic status and management of urine drainage independently affected essential duration of intravenous antibiotics treatment and regression coefficient estimates of those factors respectively were 0.998, 0.890, 2.487, 1.462, 1.293 with constant of 2.464.

Conclusions: Our preliminary multiple regression models for predicting duration of intravenous antibiotics treatment may be useful to judge the timing of changing treatment strategies for patients who would not improve at around estimated intravenous antibiotics treatment periods. If vital signs were stable, it may be acceptable to judge urine drainage from above the urinary stone at around two days after intravenous antibiotic treatments.